Notes from UNH Zoology 745: Insect Biology & Evolution

Zoology 745/845 Insect Biology and Diversity Or ―How Crotches can be hurt by arthropods‖ Or ―What plants are a PAIN IN THE ASS‖ Fall 2003 Wednesday, Sept 3 This is the introduction. There are estimated to be 16,000 species of insects in NH. There was an ATB (All Taxon Biological) inventory done in the Smokey Mountains. All organisms were quantified. To determine diversity, you must know the organisms. To gather insects, light traps, passive traps, active sifting, kicking, and seining are used in pristine and disturbed areas. The UNH Sustainability Office has a Biodiversity Education Initiative. Biodiversity can express stability. As biodiversity increases, so does stability. Monospecies are the best way to use our ability to distinguish forms. A voucher specimen is a representative example. The easiest parameter, but not as specific, is species richness which is simply the number of species found in a location. More specific, but more complicated is rank abundance which takes into account numbers present. In this class, we are sampling in the fall when many adults are present, but not as many as the summer peak. Of course, there are a few in winter, but not many. Friday, Sept 5 Evolution (Arthropods & Insects) Morphological characteristics work as well or better than a single gene comparison. A total evidence classification often called evolutionary systematics is useful. The first 4 groups of organisms to emerge onto land: 1. Bacteria 2. Fungi 3. Plants 4. Arthropods Several lineages of arthropods emerged simultaneous: Arachnids (scorpions), insects which were the first truly terrestrial organisms to emerge, plants, higher vertebrates. Only a few branches of life occur on land. Predominantly the groups today are plants and insects. Cambrian Period (543-490 m.y.a.) Life began here. The first multicellular organisms appeared. The Velvet worm, Hallucegenia appeared then. A burst of life occurred 500-490 m.y.a. Ordovician (490-443 m.y.a) /Silurian (443-417 m.y.a.) Diversity in the ocean occurred with many trilobites. Many types of Arthropods: 1. Chilicerates: sea scorpians, teripteriats, (spiders and scorpions) 2. Mandibulids: Euripterids (length=3 m) gave rise to terrestrial organisms, ate fish, drove fish evolution toward plates for protection. Bacterial mats of fungi and algae occurred along the margins of lakes and oceans. Centipedes grow there. They are close to insects, but not yet insects. 1 Devonian (417-354 m.y.a.) Complex landscapes with an increase in vascular plants. Organisms: scorpions, colembra & monura(most primitive insects), trees, ferns, horsetails, club mosses, associated insect fossils. The oldest insect fossil found from mid-Devonian: Archionathin found in Quebec. Scorpions on land came from the marine environment. There was a major split: Insects which breathe by way of trachea and Chilicerates which breathe with book lungs. Monura is an extinct order. Some winged insects did appear at this time. In general, insects had reduced legs on the abdomen which have become lost or modified. Carboniferous (354-290 m.y.a.) Organisms on land: Gymnosperms, club mosses, complex forests, winged insects which became extremely diverse and LARGE. ex: Mayfly with 46 cm wingspan with functional biting mouthparts for predation. Trodonata (early dragonfly) with 71 cm wingspan. 50% of fauna had piercing/sucking mouthparts which were long beaks to eat the strobili (cones of club mosses, conifers, gymnosperms. 50% could not fold wings. 50% could. (Today, neoptera, wing folds over back make up 95% of insects. 5% are stiff winged paleoptera dragonflies and mayflies.) Wings were preserved from this period. Permian (290-248 m.y.a.) Early later permian (260-250 mya) there was a single land mass with the US at the equator. Large swampy forests such as Mazon Creek were predominant there. Scorpionfly-nanocloristidae, mecoptera—the one family that still exists from the Permian (245 mya) Most insects come from modern fauna. Many families we see today were present with the Dinosaurs Triassic, Jurassic, & Cretaceous periods. Many of the genera present in the Tertiary (65-1.8 mya) are present today., even some species look similar! These are old lineages. Mammals started in the Cretaceous period-144-65 mya Monday, September 08, 2003 Arthropod Evolution Arthropods are thought to evolve from a segmented coelomate worm like an annelid since some annelids have 1 pair of segments per segment. Example: A sand worm that has appendage pairs on each segment. The next step in evolution would be cephalization which means getting a specialized head. Another segmented coelomate group is Onychophrans called velvet worms. The ancient annelids split into two groups—modern annelids and onychophrans that then gave rise to the modern insects. Onychophrans has obvious segments and a head. Metamers/somites are control by HOX genes and are repetitive body divisions. Evolution occurs initially by duplication then by reduction. Insects have 6 metamers in their heads, 3 in 2 the thorax, 11 in the abdomen. Scorpions have many metameres. Spiders have HUGE reduction from the end mostly within the head. Groups are used to look at the HOX genes, compare for similarity. The segments are embryologically added. Homologous functions of segment groups establishes related groups. What happened to the segments after the head? Insects the 1 st 6 segments went to the head. In spiders, the 1st 6 segments went into the cepholothorax or prosoma. Lobopods (head-foots) are all decedents into one of the two following groups: Onycophra and Arthropods Characteristics: 1. Schizocoeloas metamerism: protostomes. Coelom—mesoderm formed by splitting of clusters of cells. 2. Double ventral, solid nerve cord 3. Dorsal & ventral longitudinal muscles and circular muscles in each metomere. Each segment has a ganglion. 4. Dorsal blood vessel with forward proceeding peristalsis which means pushed forward from posterior end to head with a few holes in the posterior end of the tube. 5. Open circulatory system with each segment sort of sealed off. The Mixocoel allows blood sloshing around in the bug sack. 6. Chitinous cuticle in insects is hard and excreted by the epidermis. 7. Meroblastic, only part of the yolk undergoes fission so the embryo grows on the surface of the yolk, yolky eggs. The developing embryo goes posteriorly then takes over the whole yolk. 8. Respiration by trachea (not all arthropods use trachea—spiders use book lungs.) Trachea are outgrowths of the cuticle that goes to stationary cell tissues to deliver oxygen and remove carbon dioxide. Ultimately oxygen is diffused to cells by tracheole General Evolutionary Trends—4 MAJOR TRENDS 1. Reduction and specialization of metameres. Reduction is not obvious. Specialization is obvious. Tagmata are areas of the body evolved for certain functions Segment-looking things might not be metameres. Insects: Head for eating and sensing, thorax for movement, abdomen for digestion, excretion and reproduction Centipedes and Millipedes: Head for eating and sensing, body is the thorax & abdomen Spiders: prosoma or cepholothorax is the head and thorax combined and the opisthosoma which is the abdomen. 2. Reduction in the number of appendage segments. a. Insects today have 6 segments in leg. Some have 7. b. Arachnids have 7 leg segments c. Jarmilla Kuklova-Peck used carboniferous and Permian fossils to state that originally there were 11 segments in the arthropod leg. (10 can be believed by Chandler) 3. Movement of mouth posteriorly with a recessed mouth. a. Insect mouth between 3rd and 4th head segment of insects b. Spiders have the mouth between the 1st and 2nd head segment 4. Growth of the pleural area 3 a. A harder cuticle was developed in response to animal predators b. The pleuron grew larger to accommodate wings and legs. c. The tergum and sternum were covered with harden plates Wednesday, Sept 10 Characteristics of Arthropods 1. Layer of Chitin which creates the exoskeleton a. Composed of protein or carbonate salts b. Chitin give flexibility, protein (arthropodin) gives hardness, then tanning occurs helped by sclerotin c. Crustaceans and millipedes use CaCO 3 to harden shell d. Driven probably by protection from predators 2. Arthropods MOLT predictably a. Hormones produced which leads to interior part of exoskeleton being digested b. Epidermal tissues grows so the new skin soft, and muscles have nothing to push against c. Aquatic insects suck in water to tighten the skin and get d. Terrestrial insects suck in air to tighten the skin and get e. The process of skin hardening occurs again 3. Regionalization and specialization 4. Jointed appendages with distinct segments Number Name Description [Epicox] Engulfed into plueron, fused in the basal legs. Had appendage which is now the wing [Subcoxa] Also engulfed into plueron 1 Coxa Point where leg moves @ body 2 Trochanter In the crustacean, it is the basipodite. [2nd Trochanter] Only in dragonfly nymphs, crustacean legs 3 Femur Dicondylic joint 4 Tibia Combines with Femur to make the Dicondylic joint [Patella] Became fused into tibia 5 Tarsus Can be a secondarily segmented; tarsomeres 6 Pretarsus Claw or claws Lobes on legs are called exites on the outside of the leg which became the wing on the epicoxa Lobes inside of leg are called endites which became gills on lobsters Friday, September 12, 2003 Unique features of Evolution Basis for classification are the unique features. Head structure the number of segments makes a tagmata. Document the segments for comparison Embryological evidence for evolutionary connections 1. Appearance of appendage pairs 4 2. # of embryonic metameres 3. coelomic sac 4. HOX genes—in truly segmented organisms undergo schizocoelm Each segment has a ganglion in insects. Flatworms have ladder types nervous system Each somite has an appendage pair Segment is not the same as somite. A segment is simply a division of the body we c an see. A somite is a metamere—a repeating body segment. The acron or prostomium has the mouth and is not repeating. The telson has the anus. Appendages from the 1 st 5 somites became feeding parts in insects Appendages from the 1 st 5 somites became legs in spiders Types of Arthropods: Subphyla: Trilobites  Extinct at the end of the Permian, about 240 mya  Mouth between 2 nd and 3rd segment  Have antennae  3 body divisions: head, thorax, and pygidium (tail end)  Biramus appendages Subphyla: Chelicerates  Mouth between 2nd and 3rd segment  Lack antennae  2 body divisions: prosoma (cepholothorax), and opisthosoma (abdomen)  Present day ones lack biramus appendages, although some had them in the fossil record Body part Appendages Acron no appendages 1st somite no appendages nd 2 somite cheliceraefeeding tube things 3rd somite pedipalpscatching food/prey th th 4 -7 somite Walking legs Class of Chelicerates: Merostomata Horseshoe crabs with 3 genera, 4 species today Class of Chelicerates: Pycnodonida Sea spiders Class of Chelicerates: Arachnids Chelicerates, pedipalps, sting for defense, not predation, not too venomous, 4 prs of walking legs Subclass/order of Arachnids: Tailed/whip scorpions Catch and crush prey, long tail that sprays acetic acid 5 Subclass/order of Arachnids: Spiders Chelicerates are long, have a prosoma Subclass/order of Arachnids: Ticks/Mites 4 prs of walking legs, pedipalps enclose the chelicerates or are fused with them. This is called the hypostome which takes hours to embed in your skin. Diseases are bad but not deadly out here. Subphyla: Mandibulates  Mouth between the 3 rd & 4th segments of head  Mandibles are feeding appendages & are the primary appendages on the 4 th segment or the 3 rd somite  Have antennae  Compound eye  Biramus appendages Subgrouping of two classes:Myriapods:both Diplopoda and Chilopoda 2 tagmahead & body 1 pr antennae Class of Mandibulates: Chilopoda  1st to show up in fossil record  1 pr of appendages per segement  max #segments:177, min # segments:15  predators  Toxicognaths are the first appendages after the head and have toxin. Acron & 6 segments make the head Class of Mandibulates: Diplopoda  Acron & 5 segments make the head  1 pr of appendages per segement  2 segments make up diplosomites  max #leg pairs:200, min # leg pairs:11 (?)  detrivore or herbivore Class of Mandibulates: Hexapoda (insects)  3 tagma: : Head for eating and sensing, thorax for movement, abdomen for digestion, excretion and reproduction and much of the circulatory  modified for life on land (terrestrial)  eggs have cuticle to minimize water loss  body has waxy cuticle to minimize water loss  One pr of spiracles per segment on thorax and abdomen. Air enters the body and is moved by muscle contraction posteriorly  Internal fertilization with a spermatophore  Head is the acron and 6 somites Body part HEAD Acron Appendages labrum Ganglion labral ganglion 6 1st somite 2nd somite 3rd somite (intercalary) 4th somite 5th somite 6th somite THORAX Prothorax Mesothorax Metathorax ABDOMEN One To 7 8&9 10 11 12 no appendages antennae no appendages mandibles maxillae labium protocerebrum Brain parts dentocerebrum tritocerebrum subesophageal ganglion ―‖ ―‖ legs wings and legs wings and legs nothing--Most groups missing appendages except for mayflies and other ones with issues Male & Female genetalia Nothing Cerci Telson Wednesday September 17, 2003 Unique features and major nodes of Insect Evolution 1. Hexapod condition: 6 legs, 3 tagmata The first major split was Apterygota/Endognatha and the Ectognatha Endognatha: lack wings multisegmented antennae mouth parts completely enclosed in parts so they can’t bite Ex: Diplora, Protura, Colembembola Ectognatha: had 3 segmented antennae and exposed mouth parts The second major split was Archeognatha (old mouths, 1 pt of articulation in the mandible) and ones with 2 pts of articulation in the mandibles The third major split was Thiosonura (Odonata and Ephemeraoptera) and the Pterygotha Thiosonura (Odonata and Ephemeraoptera) have stiff wings that don’t fold over the body. They fold up or out, not over. Also called Paleoptera The others flex wings over the body, which was a strong selective pressure allowing prey to escape predators by getting into small places and allowing the predators to follow the prey. Then the Pterygotha split into three branches:Orthoptera, Hemimetabolus, Holometabolus. These have a sclerite at the base of the wing that flops and brings the wing over the body. Hemimetabolus,: incomplete metamorphosis: egg, larvae(nymph), adult for a gradual change. (ex: Hemiptera, lice, true bugs) Piercing/sucking mouthparts. Small anal area of wing. Holometabolus. 88% of insects fall into this category. Complete metamorphosis: egg, larvae, pupae, adult for a distinct change. Ex: wasps, Lepidoptera (crysallis is covered with the skin, not silk, caddisflies, diptera. Hormones trigger development. Chewing mouth parts. 7 Orthopleroids: Large anal area of wing. Incomplete metamorphosis, chewing mouth parts. Pleuroptera, Orthoptera:katydids. Notes: Imaginal disks become wings Insects with long antennae like the ants really only have 3 segments. The parts are scape, pedicle, and flagellum. The flagellum may appear to be many segments, but not really. All these parts are antennomeres. The segment distinction comes from whether there are muscles between parts or not. Friday, Sept 19 Wings and Flight Most wings are winged at least primitively. Flying insects are unique because they have wings that come from their anterior section of body. Others that truly fly have wings that are modified legs: Birds, reptiles, bats. BIG QUESTIONS: 1. How do they fly? 2. How did wings evolve? 3. Are wings homologous among insects 4. Why do insects have such fast wing beats? How do they fly? They use paddle-like wings. Obviously they move their wings which are large, flat surfaces moved by muscles. A Swiss physicist said ―Bumblebees can’t fly‖ in the 1930’s because with a path that moves back and forth can’t move according to Reynolds number. The inertia/viscosity is what calculates it. Also, small object going slowly would give a low Reynolds number They use fluted or pleated wings. The veins in the wing make the wing into the shape of an aerofoil. That means, in cross section, a wing is not flat, but rounded. Like a wing of a plane, the wing creates lift. Wings of insects also have pterostigma which is a spot on the wing that has more weight. Once the wing is lifted, gravity brings the wing down since it is heavy. This is calculated since the amount of energy that insects exert to fly is less than physicist have calculated. Not only do insects have beating, aerofoil wings, they also twist the wings down on the power stroke and twist up on return to reduce drag. Mayflies and dragon wings have independently moving wings. The movement is rapid and unpredictable. This is non-steady with high lift. Most other insects have linked wings. It is the veins of the wings that have evolved to make the wings twist functionally. Wings also create vortices as they move through the air. The downstroke creates a vortex that assists to lift the wing. The upstroke creates a vortex also that assists in bringing the wing down. The ―clap’n’flap‖ helps even more. The wings meet at top of the beat. A vacuum is created so that additionally lift is created with additional vortices. 8 Most insect wings beat together, but not the grasshoppers and other primitive types. These independent moving wings can beat together if needed. The muscle inserts directly on the wing base for Paleoptera (Odonata, Ephemeroptera, and Orthopterids) Other insects have wings attached and described as: 1. Frenulate: Hairs going in opposite directions that link together 2. Jugate: Jugal lobe of wing acts as a clip to hook wings together 3. Amplexiform: Wing coupling where the front wing overlaps the back and controls the back section 4. Hamulate: A row of hooks on one wing grab onto a vein of the other wing. The external control for wing movement is when the tarsi (legs) no longer touch the ground—a direct reaction Monday, Sept 22 Cross section Wings and Flight (pt 2) side view For primitive insects, grasshoppers, mayflies, and dragonflies. On the upstroke, the dorsal ventral muscles, a cluster of muscles from sternum to tergum, contract and make the somite shorter by pulling down the tergum. This makes the wings GO UP! On the downstroke, the sternopleral muscles, attached outside of the pleural process to the wing, contract and the wings go down. For advanced insects there are direct and indirect controls of the muscles. The upstroke is the same as the above description. The downstroke however is also indirectly controlled by muscles. Resilin is the rubber-like pad that stores energy from the upstroke. THIS IS THE CLICK MECHANISM Question #2: Where did the wings evolve from? a. Where on the body did wings evolve? b. Nature of function of protowings? c. Selective pressure that led to evolution of wings? d. Were ancestrals terrestrial or aquatic? Winged insects appeared in the fossil record in the Carboniferous period. What were they first used for? Theory #1: Protonotal Theory: Wings came from the turgum A. Lateral extension of tergum a. Lobe-like paranota act as parachutes b. Evolved to act as a gliding surface c. (Somehow) became articulated, enervated, musculated, and therefore wings! NOT BELIEVABLE! d. Dorsum is the tergum of the 1st thorasic section. 9 e. Why would this happen? Thermoregulation or mating characteristics i. The paranotum can heat up and warm the organism ii. The paranotum can be colored and attractive f. PROBLEMS: Why are wings present in immatures? i. What would be the value to aquatic insects? B. Part of the leg—Wings come from lobes on the leg a. Epipodite is an exite at the base of the 1st trochanter b. Homologus to epipodite of the crustaceans biramus appendage c. ―Stylus Theory‖: wings are remnants of leg from the trochanter that was first modified as a gill i. leggillgill platewing ii. Then the whole leg became the wing d. ―Epipodite Theory‖: Wing is an exite from the leg higher up, like the epicoxa. i. Gills come from the exite on the 1 st trochanter Are the Wings homologus across all insect groups? Yes—a single point of evolution for wings despite the variety in wing venation. Wednesday, September 24 Wings Are the Wings homologus across all insect groups? Yes—a single point of evolution for wings despite the variety in wing venation. Ribs in the wings are called Veins. In 1870, Hagen named the wing veins=costa(c), subcosta(sc), radius(r), medius(m), cubitous (cu), and anal(a). These ribs make the wing pleated or ―Fluted‖. Kukalova-Peck added more prs of veins. Additionally, she detected the precosta (pc) and the jugal (j). The pc was in the beginning of the wing and the j followed the a. These veins come in an anterior and posterior pair. These help to prove that wings are homologus since the venation came form the same original location. The meso and metathorax has wings. The Flies-Diptera-appear to have lost their hind wings but actually the wings are still there. The wings are modified to Halteres which are small with a bulb at the end and act as a gyroscope to provide stability. Coleopetera have powerful hind wings and the forewings are thickened and hardened. The forewings are called elytra (pl.) and elytron (sing.). These are fixed areofoils. The power wings fold and have hairs to grab and tuck into the dorsal side. Hemiptera have wings that are half membranous and half hard. The whole wing is called Tegmina or hemelytra. They are distance flyers, not fast flyers. Strepsiptera—a parasite on wasps with one pair of hind wings and reduced forewings called psuedohaltere and they move slightly. These are only in the adult males. Wings are ALIVE! There is a tracheole and a nerve and a blood channel running through the wing. The membranous areas die first and in alcohol, the wings puff up. How can the wings beat so fast? Depolarization of membrane is a nerve pulse. The human muscles contract 100Hz per sec. (Hertz is a cycle). Insect muscles contract between 1 and 1000 Hz per sec. Slow flyers have direct muscle control of the wing. The Orthopteroids (slow flyers) have slow wing beats, less than 60 beats per sec. For every muscle contraction, there is one nervous impulsea 1:1 ratio. High frequency wing beaters have muscles that set their own pattern of contraction. Wing beats can be 400 times per sec. The nervous impulse goes once every 4 wing beats. There is 1 impulse for every 40 beats. 10 Myogenic or asynchronous beats: There are fewer nervous impulses per wing beat. How does this happen? There are antagonistic muscle pairs for the wings. The thoracic flight muscles or tympanum of the cicada. As one muscle contracts, the other antagonistic one relaxes. The relaxing muscle is an elastic muscle which has a response: to contract without a nervous impulse when it is stretched. (WOULDN’T THAT ONLY ALLOW 2 WING BEATS PER NERVOUS IMPULSE?) WHY DOES THIS HAPPEN? Insect muscles don’t contract much, not a very far distance. The wing is in the body at one end and can’t move large distances. The fastest recorded insect is the 33.7 mph of the sphynx moth. It has been stated that the Bot fly went 400 yards in a second which is MACH 1—30 miles a minute? Stinging wasps fly at 7 mph. Monday, Sept 29 Development and Metamorphosis Body Wall-also called integument—it is the outside covering of an insect. These are terrestrial animals (really?) The outer layer of insects is a dried secretion. Animals and plants are covered with dead dry cells on land. The outer layer for terrestrial organisms must be resistant to water loss. It protects insects. Pest control ideas attach this covering. How is it secreted? The Chitinous exoskeleton has many functions: 1. Protective covering to prevent chemicals from coming into the organism. It is dead tissue 2. Serves as an exoskeleton and endoskeleton 3. Sense organs are in the cuticle 4. restricts water loss 5. Produces color or patterns. The Integument cross section: Epicuticle Make up cuticle Procuticle Epidermal cells Basement cells Epidermal cells secrete cuticle and are flat most of the time. These cells wrinkle when the organism is about to molt. The cuticle is a secretion of the epidermis Epicuticle can have 4 layers: 1. Cement layer which is the outer most like a coat of shellac it acts as protection and not all insects have this layer 2. Wax layer is a long chain of waxes tightly packed and prevents water movement. 3. Outer Cuticulin minimizes the effects of wounds 4. Inner Cuticulin also minimizes the effects of wounds A way for humans to kill insects is to give place them in silicaceous or diatomaceous earth. The insects crawl through, get scratched and dehydrate from the scratches. Procuticle is initially all 1 type. As the cuticle, made of chitin and proteins, ages, the outer exocuticle becomes HARD and the inner endocuticle remains soft and flexible. By secretion of quinones from the epidermis, the layers harden. The quinones cross-link the proteins to make them hard. The protein used here is arthropodin which produces scelerotin. Immature mandibles are actually harder than adult mandibles as is the abdominal sternite of immature locusts. 11 Sclerite is defined by a boundary and it is a hardened area between membranous areas. A Sulcus is a groove between two sclerites. A Suture is a ridge between two sclerites. The integument or body wall is useful and important for molting and metamorphosis. This is post embryonic development: changes after hatching and two processes. Molting must happen since insects have an exoskeleton that prevents expansion. Metamorphosis is a change in form over time. Many stages have distinct body types that outline sharply different periods in an insect’s life. EggimmaturePupaAdult. Only a few insects molt as adults. Between molts, the insect stage is an ―instar‖ Examples: Silverfish: 60 molts Mayflies:45 Molts Dragonflies: 20 molts Adult molters: Endognatha (Apterygota), Mayflies—once from subimago to imago (adult). Some adults bore into dead wood and may molt many times even if they are a complete metamorpher. Less molting is a derived characteristic physiologically. Primatives maintain juvenile glands. More advanced insects loose the juvenile glands. Ametabolous :No metamorphosis. From an egg, the adult-like larva hatches. Typically these molt as adults. Hemimetabolous incomplete metamorphosis: Eggimmature Adult. The immature gradually increases in similarity to the adult and has growth of wing pads. Holometabolous complete/complex metamorphosis: EggimmaturePupaAdult. No wing pads are present in the immature. Lots of change occurs in the pupa. Wednesday, October 1 Metamorphosis The pupal form varies. Chrysalis is most form really. It doesn’t look like the larva or the adult. The Chrysalis is not covered by silk—instead by integument. Metamorphosis is controlled by 3 endocrine centers. 1. The brain, corpora candiaca complex 2. The corpora allata—sits behind the brain and is a clump of nerves 3. Prothoracic glands—sometimes in the head. Molting is controlled by the molting hormone: ECDYSONE. The act of molting is ecdydis. The Ecdysial line splits to free the insect since it is a weak zone. The first stage: The insect is happy. It has had one large blood meal and stretching the exoskeleton and the brain receives this signal. The median neurosecretory cells exists in the brain (MNC). Other signals: Grasshoppers feed constantly so the signal is activity in the pharynx. If there is a minimum of nutrition, fat reserves, a minimum head size that has been reached, or just passage of time, the insect sends out molting signals. It is time to change to the adult so the ―Brain Hormones‖ are produced. They go to a certain area to be concentrated. They are now called PTTH: prothoracicotrophic hormones. The second stage: The PTTH is concentrated in the corpus candiaca. PTTH is stored here 12 The third stage: The PTTH is stored and released when there is enough hormone—after 2-3 days. If enough hormone to stimulate molting accumulates in less than 2 days, the insect won’t molt. If it takes longer than 3 days to collect enough PTTH, the molt is funny. This is the critical period. The Fourth stage: The ―Prothoracic‖ glands produce ecdysone. It is in the second half of the instar period— Polydnaviruses prevent thocorasic glands from breaking down—paralyses instar—keeps the young as food for parasite—parasite always has virus. Wasps leaves and takes virus with them. The corpora allata has the juvenile hormone levels that are critical in determining the form. The story as follows: 1. the levels of JH are high with 1 peak of Ecdysonea larger larva 2. High then low JH levels and 2 peaks Ecdysonea pupa comes out 3. No JH and 1 Ecdysone peak  adult MOLTING Apolysis is the separation of epidermis from the old cuticle and is triggered by ecdysone Ecdysis is the removal of the old cuticle. During Apolysis the epidermis cells multiply. Ecdysone levels control the following: 1. The epidermal cells become larger 2. They separate from the cuticle 3. Space is created between the epidermal and cuticle layers. 4. Epidermal cells secrete an inactive enzyme molting fluid into the space 5. New epicuticle is secreted then the molting fluid is activiated, the old endocuticle is digested and reabsorbed into the body. Old chitin is the only wasted part. 80-90% of the old cuticle is reabsorbed. Ecdysis is caused by other hormone levels which lead to a change in behavior. 1. Ecdysis triggering hormone—changes behavior 2. Eclsion hormone—changes behavior 3. Bursicon What is the new behavior? An insect finds a high humidity place, stops moving and is in a guarded place. Also, contractions of the abdomen forces blood to the front of the body to break the ecdysial line—line of weakness. The insect comes out and waits again. Bursicon is the hormone that hardens the cuticle. It is produced in the brain. The insect has .5-1 hour to stretch out the new cuticle and epidermis. Then it is solid. How do you use hormones to disrupt insect lives? There are 3rd generation insecticides that are Insect Growth Regulators (IGR). Biorational insecticides are keyed directly to each insect and therefore unique and non-toxic. Problem: Apply to immature and won’t kill them until they are adults. IGR’s Are: 1. Anti-metabolites—resemble essential nutrients and block biological pathways essentially mothproofing. 13 2. Fagodeterents/antifeedents—When insects ingest IGR’s, they stop feeding, or experience problems with metamorphosis. EX: extract from the Neem tree makes Azadirachtin –two parts one antifeedant and one poison. 3. Hormone analogs—JH analogs: Methaoprene, tradename: Altosid. When you spray, insect molts in a monstrous way. EX: mosquitoes have large larvae that can’t survive. Ferns have analog of JH so they are not chewed much by insects. Cotton—most heavily pesticided crop in the world. 4. Ecdysone analogs: molting hormone antagonists triggers a molt when insect is not ready. 5. Chitin synthesis inhibitors analog—a bursicon analog. Insects are trapped in skin that it can’t shed. Or maybe just create/produce insect hormones—not so easy. Monday, October 6 Metamorphosis/Reproduction Larva Specialized for feeding All time is spent feeding Often in different habitats from where adults are found Pupa ―Resting‖ Stage so insect is not eating However this is really an active time of growth Adult Feeding is reduced in some groups. Adults are specialized for reproduction and dispersal. In groups where the larvae have high quality food to eat, the adult doesn’t usually eat. The exception would be the beetles which are herbivores eating pollen and nectar. Reproduction Problems with being truly terrestrial are that reproduction can be more difficult. Note: Insects are truly terrestrial like the plants, higher vertebrates (birds, reptiles, mammals) Beetles that are aquatic are secondarily aquatic. 2) Internal Fertilization of Insects: (Some crustaceans also directly transfer sperm) i. Female has an internal egg, the male placed the sperm where it can reach the egg. Development of the egg covering—the Chorion Covering has aeropyles which are holes. The holes for fertilization are called micropyles which are large enough for sperm which is long and thin to get in The point of the Chorion is water loss prevention Appearance of and ovipositor. This is unique to insect. It is an egg depositor that comes from the abdominal appendages. It occurs usually at the apex of the abdomen. Wasps bore into wood or another creature to lay the egg Katydids saw with the ovipositor and place the egg inside of a twig. 14 2) a) b) c) 3) a) b) c) d) e) Ovipositor is a derived organ. Most insects have ovipositors. i) Type I is an appendage of the abdomen ii) Type II is more derived and not so hard. Internal Reproductive organs Essentially the males and female make up are very similar. 1. A pair of gonads (ovaries or testes) 2. Pair of exit ducts (lateral oviduct or vas deferens) 3. shared media duct (median oviduct or ejaculatory duct) 4. external genitalia (ovipositor or aedeagus) The female has a spermatheca which holds and nourishes the sperm. Usually 1-3 spermatheca. The spermatheca is musculated and capable of controlling the excretion of sperm. The micropyles are on the end of the egg to allow in the sperm. Regulation is either spermatogenesis or ovogenesis. Hormones that control this are Juvenile Hormone (JH) and Ecdysone. Ecdysone is produced in the prothoracic glands and will disappear in the adult after the last molt. Then the Ecdysone is produced in the ovaries. Hormones are active in both sexes. JH is the primary coordinator of the reproductive process. World Records: Male reproductive system with the longest sperm is the Drosophila bifura whose sperm is 58 mm long, 20 times the length of the body. 25 sperm are created at one time. Many Drosphila have sperm which is 15 mm long which is still awful huge. Most prolific insects is the cricket which produces 1.49 million sperm in a spermatophore. Spermatophore: Males produce the spermatophore which is a glob of sperm surrounded by secretions of the accessory glands. The spermatophore then concentrates the sperm into a case. There are nutrients in the secretions. The female will take out the spermatotphore and eat the covering for nutrition. A different role for the spermatophore is to plug the female to prevent other fertilization. Spermatophalyx (*not sure what this is) Spermatophores are commone in more primitive groups such as the crustaceans, mryipods, and arachnids. In more derived groups such at the holometabola, there is a penis, Aedeagus, which is an intermittent organ. This organ places free sperm at the entrance to the spermatophore. The Aedeagus is diagnostic for species. It is 1-4 mm long Outside of body Parameres Wednesday October 8 Reproduction Male reproduction system. 1. Sperm: bound in spermatophore in primitive groups: apterygotes and orthopteriods such as cockroaches without an intermittent organ (missing the aedeagus). If there is an aedeagus, generally there is no spermatophore 2. Accessory glands: produce seminal fluid and nutritious substances. Normally 1-2 pairs of accessory glands. In the cricket: 600—not clear if that is glands or pairs of glands. 3. Aedeagus is the organ. The male gonopore is on the membrane after the 9 th segment. 15 f) Female reproduction system 1. Spermatheca receives and stores mature sperm. It can be stored for 4 years. Honeybee and termite queens mate once. 2. Accessory glands: a. produce protective coating called the oothecae in cockroaches and mantids. This is a sticky, foamy mat made by collateral glands. b. Glands could make venom in stinging hymenoptera. c. ―Milk‖ glands make nutrients for eggs. 3. Development of the ovipositor from the appendages of the 8th and 9th segments. a. Strongly modified. b. 2 exites and 1 eudite make the ovipositor. The honeybee has small ovipositor, workers have them too. c. Type I ovipositor: ovipositor lacking in this group, (A ―diddly squat‖ type) i. Lepidoptera ii. Diptera—abdomen is telescopic, segments 2-5 visible, 6-11 intermittent and appear when needed. iii. Coleoptera d. Type II ovipositor: long extensions that are modified or distinctive from segments 8 and 9. Mating Behavior 1. Locating and recognizing members of opposite sex—usually these initial steps are auditory or visual. a. Crickets and grasshoppers are auditory b. Exception: Lepidoptera males follow chemical cues 2. Tactile or chemical cues are the next step in recognition a. Does this one feel or smell right? b. Fireflies have a unique set of species specific dances. The males in the air have a blink, blink, blink, or wiggle, wiggle, wiggle, or BLINK, BLINK way to attract females on the ground. The females are larvae like and flash in response to the male. 3. Courtship pattern of behavior is characteristic of species: a. Dance flies or balloon flies. The males fly in clusters, capture the prey and wrap prey in silk as present for female. i. Several Trends have exist: 1. Prey items are given to the female and she is non-predatory 2. The substances are nutritional 3. A male could give her something inedible as a balloon 4. The female’s secondary sexual characteristics are Autogenous so the male selects the female. b. Nuptial gifts drive courtship. Chemicals for protection or nutrients for food for female. i. Meloid beetles produce fluid canthanidin—a chemical irritant called ―Spanish Fly‖. It is a repellent. Horses can die from this poison. ii. Beetles pick up chemical, ingest chemical concentrates in reproductive system and passes canthandin along in seminal fluid. This chemical goes to egg and protects it. Friday, October 10 Mating Behavior (con’t) Already talked about location and courtship. Now: Copulation 16 Indirect copulation 1. occurs in the springtails. They are common in leaf litter where it is humid and moist. They place a spermatophore on a spike the female might find. 2. Indirect copulation occurs in the Apterygotes: they stick sperm somewhere, dance with female and places her over the spermatophore. Usually the male is < the female. 3. Thysanura has a head to head meeting and the male places the female over the spermatophore already placed on the ground. 4. Odonata has a very distinct way of copulating. The male places his spermatophore on a spot between the 2 nd and 3rd abdominal segments. The male grabs the female’s head with his claspers at the end of the abdomen and they fly in tandem. He grabs out other spermatophores and places his in her. In general, the females are polyandrous and mate with many husbands. Last in and first out is the last male to mate with the female is the one whose sperm will probably fertilize her eggs. Direct copulation—directly placing sperm in vagina. 95% of insects use this method 1. Hemocoelic insemination—―traumatic‖ insemination occurs in bed bugs and strepsiptera where the males directly inject sperm into the body of female. 2. Three types: a. Alleorgychus where the male has a spine at the tip of the aedeagus and puts the sperm into the body cavity. The sperm migrates through the body to the ovaries. b. Primicirnex uses its left clasper to penetrate the abdominal wall of tergite 4-5 or 5-6, rupture the wall, and inject the sperm. The sperm moves to the heart, circulates with the blood and get to the ovaries. Many sperm are digested. c. Some have a special pouch on the abdomen for reception of sperm—a spermalege or Organ of Ribaga. The pouch evolved to accept the aediagus which ruptures the pouch and deposits the sperm. The sperm migrates to the seminal conceptacle like the spermatheca and many sperm are digested. Bed Bug females depend on sperm for extra nutrients. She feeds on her own, but this is a bonus. Mating Behavior #4 Post copulating behavior 1. Ovulation: mating triggers release of mature eggs. Sperm is present. Eggs move down oviducts. Egg rotates in the fertilization chamber. Sperm gets deposited into the micropyle and egg is fertilized. Mating triggers release of ecdysone. 2. Oviposition of individual eggs or large masses of eggs. Cockroaches lay eggs in layers called ootheca—a row of fertilized eggs deposited for protection 3. Male behaviors to protect their females: a. Non-contact guarding b. Post copulating riding for seconds or days c. Reduce receptivity, some species only mate one time such as screw worm flies. Story: Screw worm flies deposit eggs on cuts of animals. This is a major loss of cattle in the SE and SW. Wounds on cattle attract the females. That attracts more and more females. The key to their downfall is that they only mate once. So the solution was to radiate males to make them sterile. Then the sterile males were released from an airplane and mated with the females. She then can’t have any babies. 4. Males can physically block the vagina or spermatheca with a plug that can be nutritious or not. 17 5. Seminal fluid can contain an anti-aphrodisiacs which swell the spermatheca 6. Male mosquitoes pass matrone to female which blocks the CNS and prevents her from sending signals. Vivarity 1. Oviparity: egg contains all the nourishment and embryonation is in eggs that are laid. Development of the embryo happens outside of female body. (most common form) 2. Ovoviviparity: Embryonation occurs in the female. Egg laid and larvae is ready to hatch. Or the egg is laid and the larvae are deposited by the larvapositor—very close to hatching or are hatched. This gives the larvae a head start to life like carion feeders or parasites. 3. Viviparity: eggs retained and embryos nourished. Few offspring are cared for in a vagina modified into a ―uterus‖. One of three possibilities: a. Larvae ready to pupate b. Pupa hatched c. Living immatures that are almost ready to reproduce and this is Paedogenesis. i. Ex:Tsetse flies and Sheep Ked flies ii. They are pseudoplacental: little yolk to give nourishment from psuedoplacenta. Result is mature immatures are born. Aphids are an example here. Parthenogenetic— adentrophic viviparity---few eggs and accessory glands become ―milk‖ glands. Embryonic development 1. Sexual systems are normally ―diploid-diploid‖ Males and Females have 2N like humans. 2. ―Haplo-diploid‖ Usually Male is 1N and Female is 2N. In a few cases like the Lepidoptera, the Female is 1N and the Male is 2N. a. Variations would be Homogametic: XX b. Heterogametic: XY: With XXfemale, XYmale; XO: XYfemale, XOmale Parthenogenesis: Production of haploid or diploid offspring from unfertilized eggs. This can be described by process or sexes produced. Process 1. Apomixis: No Reduction division. Basically this is meitosis. No meiosis occurs. The gametes replicate, divide and that is it. Daughters are gametically identical to moms. 2. Automixis: Meiosis followed by fusion. Genes can crossover. Either genes replicate, divide, fuse and divide, or replicate, divide, divide, and fuse. Pattern Derived or Sex based 1. Arrhenotoky: Haploid-Diploid parthenogenesis. Males are parthenogenicproduced without sperm. 1N males are haploid and 2N Females are diploid. EX: Honeybees and other social hymenoptera Depending on conditions, usually the females are workers. Examples: Thysenoptera (sp?) thrips Homoptera: Scales and white flies Hymenoptera: social wasps NON Insects: nemotodes, rotifers, mites RESULTS: reduced heterozygocity. Rapid Evolution 18 Some inbreeding Tend toward sociality 2. Thelytoky: Only females produced, 2N unfertilized eggs. 1 out of 300 only grow to adulthood. Others die in the first instars. In polyploidy—orthopteroid groups. Example in blackflies, there are only females and they are 3N. a. Strange examples: Females mate with male of other species to stimulate ovulation. Sperm is transferred, but doesn’t do anything. The behavior is what stimulates ovulation. ―Reproductive parasitism‖. 3. Amphitoky: Males and females produced parthenogentically. Cyclic groups: a. EX: Aphids: They have different forms over the course of the season. They cycle through male and females, females only, and then males and females. They winter as eggs. i. Eggs from sexual reproduction laid on a woody host ii. Eggs hatch in the spring as the woody host grows and eats the nice young green leaves. iii. When woody host is less active, the adult goes to herbaceous hosts which are active. iv. So then they reproduce offspring most successfully in parthenogentic reproduction and when the area is crowded, individuals with wings move out of the way. v. In the fall, there is a migration of adults to woody hosts. They make males by the X chromosomes being lost and the female keeping both X chromosomes. vi. The mortality and fecundity rates are very high. October 17, 2003—Friday Finishing Reproduction and Moving to Behavior Paedomorphic females in the Micromalthus debilis in the Order Coleoptera, Suborder Archostemata, Family Micromalthidae—1 species and 5 larval forms. It is rarely found and native to eastern US. Paedomorphic means the larva produce young. They are larvaform. They have a haploid system—Males are 1N and females are 2N. The process is as follows for the larva: 1. Larva develops into an adult male or female 2. Thelylokous paedogenisis (Only females produced, 2N, and are viviparous with eggs retained and embryos nourished. A Triungulin is produced. This is a larva that runs around and feeds on its host. It will molt to an adult female 3. Arrhentokous (Haploid-Diploid parthenogenesis. Males are parthenogenicproduced without sperm. 1N males are haploid and 2N Females are diploid.) Single grub-like larva male that eats its mother and hatches into an adult male. This is metrophagus. 4. The larva produces another paedogenetic larva. 5. Amphotokas—produces male or female larva Why would they do this? Escaping from a system where the males are cannibalistic. They are also specific to a niche: rotting, buried logs. Only found in Eastern US. Now it has been transported to Japan and Central America but not Europe Behavior: A response to stimuli. There are 2 types: 1. Innate: stereotyped and can’t usually be changed. This is a fixed response to a stimulus. 19 a. Reflexes: Rapid uncontrollable response to a stimulus i. Ex: Fly proboscis extends when fly lands on sugar ii. Ex: Bug is on its back and fights to turn over b. Kinesis: Random movements i. Orthokinesis: Activity due to humidity or sunlight c. Taxies: Directed response relative to a stimulus i. Phototaxis: toward or away from light 1. Positive Phototaxis is toward light 2. Negative Phototaxis is away from light ii. Chemotaxis: reaction to a chemical 1. Sense organs in the foot detect chemicals with a chemoreceptor iii. Anemotaxis: Wind is the stimulus. Bugs face into the wind iv. Thigmotaxis: Close surroundings. Bugs go for pressure on top and bottom of body. d. Transverse orientations: Use the sun or moon for orientation. This is sthe lightcompass reaction. The insect senses the sun for movement and time. i. Light lamps need the correct color to attract an insect. Bug zappers are the wrong color. They attract mosquitoes but when they get close, the mosquitoes are repelled by the light. Insects come into the yard and bite people. Yellow is the best light to use. e. Rhythm: controlled by innate time measuring. Honeybees shiver to heat up the hive in the winter by eating honey. The environment turns harsh at some point so the insect needs to stop doing what it is doing. The conditions induce these behaviors: i. Diapause ii. Dormancy iii. Migration iv. Classic Endogenous rhythms: programmed internally and are followed without the environment giving a clue to behavior change. v. Circadian Rhythms: Based on a 24 hour clock. Well, about 24 hours. The clock adjusts daily with changes in light. The clock is reset in the photoperiod. 1. the exposure to light is sensed by the brain: 2. there are reception on the insect for sensing light 3. When light is detected, hormones are produced. The hormones go to the subesophogeal ganglion (the last 3 head parts) 4. The hormone is secreted every 24 hours when the sun hits the body. A 12 hour light/12 hour dark system will be maintained in some insects and maintain the behaviors. Even with only half a minute of light, this system gets reset. With constant light, the clock is 25.3 hours. With constant dark, the day is 23.5 hours long 2. Learned: Can be changed after interaction with the environment. This is learned after an experience. This behavior can be modified by experience. Naïve bees fly off to get used to the area. Bees make 500 flights to learn the area. Ants learn to navigate with flowers and positions of things. Detail on Innate Rhythms: 20 Circadian rhythms are controlled by genes: per(period) and tim(timeless). These genes produce hormones that bind to genes and are controlled by the brain. Non-Circadian Time Rhythms are regular but not 24 hour periods. These rhythms control one-time events like emergence from the egg or pupa. When conditions are right, there usually is a mass-action. Even without the perceived cue like light or weather, the event happens. This indicates there is a time aspect to these rhythms. Example would be the 13 and 17 year cicadas. Exogenous Rhythms: responses to periodic changes in the environment. An external cue triggers these responses. 1. Dormancy: two types a. Quiescence: A temporary, short-term period of inactivity. This is a sudden, noncyclic, non-predictable response. Temporary events like a week of drought or a sudden rain cause insects to not move. However, metabolic rates and hormonal activities are normal. i. Ex: in the alfalfa after a rain, no insects are active. b. Diapause: Metabolic rates and hormonal activities are lower. No activity is occurring in the way of reproduction. This reaction is genetically governed and that determines the state of depressed development. Feeding stops and the heart rate slows down. This is a response to predictable, long term negative environmental conditions. Diapause is completely determined by predictable long-term conditions. i. Ex of conditions: wet/dry seasons, warm/cold seasons, hot/warm seasons. Insects are active in the season it works for them. ii. Ex of diapausing insects: 1. Egg diapausers: aphids and grasshoppers, some mosquitoes 2. Immature diapausers: spruce bud worm in the 2 nd instar; the cabbage worm diapauses as a pupa as does the pupae of the fall web worm 3. Adult diapausers: Colorado Potato Beetle (CPB) and other beetles and weevils. Click Beetles 4. Ovarian diapausers: Califora beetles(?) have active adults with w/o active reproduction in bad conditions. Advantages of Diapausing: 1. Allows tolerance of adverse environmental conditions 2. Allows for synchronous emergence The basis or control is hormonal/physiological. Almost always a low level of brain hormone, PTTH, which produces ecdysone and it is inactive. The level of juvenile hormone, JH, is variable. Usually it is very low, but there are exceptions to this rule. Also the presence of neurosecretory cells exist in the subesophageal ganglion. This is the diapausing hormone in some groups. Depending on the species, the diapause is always in a certain stage. This is not the same across all groups. Initiation: Typically the photoperiod controls this. Daylight length controls this. Somehow the light levels are detected by the brain. The brain senses the light intensity. There is either an ―on-off‖ switch or a gradual component here that I don’t understand. 21 Obligate diapausers: Univoltine is where there is one generation per year. This is where there is one clear specific diapause stage. Most insects have this sort of periodic cycles. A few species are both univoltine and bivoltine at the same time to cover all their bases. Facultative diapausers:Bivoltine (2 generations per year), Multivoltine (more than 2 generations per year) only diapause when it is needed. The record for a delayed voltine (less than one generation per year) is 38 years for a beetle that bores in dead, dry wood. Other examples: The black cutworm has 2-3 generations per year in Canada The black cutworm has 4-5 generations per year in Florida The black cutworm has 12 generations per year in Mexico Cues for Diapause: begins before adverse conditions arise. Photoperiod cues the insect. This is the MOST important cue. This is sensed by the cuticle or the brain. Initiates but does not TERMINATE diapause. The organism survives because it can predict harsh conditions. Short length of daylight cues most NA species Long length of daylight cues insects in the desert of CA. As the day gets longer, the desert heats up. Insects usually respond to the red wayelengths since those wavelengths go through clouds. Thermoperiod is variably important to initiate diapause. It is the Most important cue for ending/terminating diapause. Ex: The mother silk worm determines before laying if the eggs need to diapause. Once diapause occurs, temperature is CRITICAL! A criteria must be reached. That could be a certain number of days below a critical low temperature, intensity of cues, for example it must be cold for a certain length of time. Ex: Face Fly (Muscae natanellz) must spend 4 moths at 5 Degrees in total darkness. Around NH, the winters usually get cold and below freezing so this works. Those insects that diapause in the ground find a low spot and lower to 28 degrees F for 2-3 months. Wednesday October 22, 2003 Diapause details Cues are abiotic (3) and biotic (2) Abiotic Photoperiod—usually shorter light length is a cue. Universal cue to trigger diapause Thermoperiod—cue to terminate diapause Moisture—depending on the organism, this terminates or starts diapause Biotoic Nutrition—bad conditions cause onset of diapause. An example of bad food would be oak trees with low tannins in the spring make more tannins in the fall. That is bad. Crowding—onset of diapause from competition for food. 3 PHASES of diapause 1. Preparation—the trigger which can be as little as 2 days as sensitive to photoperiod. Ex: Larva of a Lepidoptera, Diataraxiaat one specific larval stage can sense the 22 photoperiod. Genetic determination of going into diapause or not. Some groups can take up to 30 days to go into diapause. A fix trigger –page 644 in Text—Odonata— develops into adult late in season. Can sense increasing photoperiod, then decreasing photoperiod around the mid June to become adult or not. Can go into diapause. If it does—then it takes another year to get to adult. a. Build up of food reserves b. Build up of molecules—sugars, proteins that allow survival during winter c. Depositions of waxes to prevent loss of water—during inactivity insect would lose water. 2. Diapause—slightly incorrect to say NO activity. There is some physiological development taking place. Typically 0-100C there is diapause development. It must happen or organism will not develop correctly. Something to do with the exposure to cold. Critical development for survival. Not well understood. 3. Termination—whatever the trigger is the insect becomes active. More rain, more warmth. Juvenile Hormone is produced. Except for groups that diapause with high levels of JH, the rest produce JH and terminate diapause. Those that diapause with high levels of JH are usually(maybe) immatures. Diapause can happen at any stage. Cold temperatures and Diapause (in text) Development of cold hardiness—to tolerate cold temperatures in the diapausers. Trigger of light or cold leads to preparation of cold-hardiness. Sudden frost often kills individuals that can tolerate the cold winter because it takes awhile to develop tolerance to cold. The best is to be exposed to increasingly cold days. It takes them a while to develop the tolerance. Higher and colder temperatures help produce tolerance substances: 1. Freeze tolerance: artic, alpine, extremely cold temperatures. HOW IT WORKS: produce a. ICE NUCLEATING PROTEINS. These are a nucleus for creating ice in between cells to prevent ice from forming inside cells. Crystals of ice form in the hemolymph not the cells. Concentration of compounds in hemolymph then causes osmosis to hurt organism. Down to -700C b. POLYHYDROXY ALCHOLS (polyols). Sugars, glycerol, prolize, sorbitol, trehalose---super coolants 2. Freeze avoidance: -150C-350C a. Supercooling with sugars and alcohols in blood. Lower the freezing point of blood with these antifreezes. Hydroxy bonds form with sugars and alcohols. TYPICAL of NH insects. Levels of these antifreezes are detrimental—poisons. Can tolerate these poisons if they slowly reduce their metabolism. At termination of diapause, the compounds are broken down slowly. If it gets really cold, it doesn’t move through body (DON’T GET THIS POINT) 3. How cold does it get? Below the snow it is insulated. Not much below freezing--250C. Without snow, that is DANGEROUS! More insects survive when there is lots of snow. Side light—humans have changed species really. There was a species that emerged mostly in October and laid eggs in the Hawthorne. Organisms of the same species emerged earlier and later and died. Then humans planted apple, plum, and other trees that allowed the ones that emerged at earlier and later times to survive. Now perhaps they are even other species 23 Friday October 24, 2003 Diapause behavior—following it something else happens. The adults require JH and become reproductively after diapause. For others, eggs, pupae, larvae have to go through more development after diapause Temperature is important to development. They are cold blooded. They don’t create internal heat to maintain temperature. Poikilothermic: depend on outside temperature. If the temperature is higher, the developmental rate increases. 25 20 peak Metabolic activity 15 10 5 0 nothing cessation cessation leathal limit 0 5 10 15 20 25 30 35 Temperature (0C) Pest control people can know temps and biology and then predict which will become active. Explain with ―Day degrees‖ can predict times of activity based on accumulated heat units. There is a THRESHOLD temperature where there is a developmental minimum temperature— development doesn’t progress below that temp. Above that temp development does progress. GENERALIZATION: 100C ≈ 500F. This works for heat active Thermal constant: cumulative amount of heat above the threshold temperature necessary for an event to occur Mean daily Temperature: ―simple average method: (daily max+daily min)/2=MDT Effective Temperature: MDT-Threshold temp If positive, add them Day degrees EX: (150C+80C)/2=11.50C Threshold is 100C, so 11.50C-100C=1.50C Add them up every day to get thermal constant to get the event to happen. 24 Painted lady thermal constant to reach adult Thermal constant of 4400C and the Threshold temperature is 120C Degree Days: Egg—100, Adult 1000 Many groups move according to predictable weather. Migration Can be tied to individuals moving because: 1. Spread—single generation movements a. Adults emerge, disperse, mate, lay eggs in a new habitat. Establish new areas and become successful. KEY: Adults die in the new habitat. b. Can be local or long distance of spread. c. Prevailing winds from LA move north to IL and insects flying in LA are carried north. Major pests in new England arrive in mid summer. They die out but do arrive: black cut worm, horn worm. These are knocked back each winter. NORMAL 2. Short term Feeding Migrations—Daily or shorter—twice daily or over a week. WELL Within lifespan of an individual a. Certain groups of insects emigrate to areas to feed and find mates and return to the breeding area. b. Ex: black flies, mosquitoes, dragonflies 3. Migration: Movement to avoid adverse/harsh conditions—―sen su lato‖ many miles of movement. Can be a short movement but very predictable movement (diapause is a type a. Flight/movement to an overwintering area close to the breeding area even if this is close by MOST NH INSECTS DO THIS! i. Crawl into bark, leaf litter or other places to hide/survive ii. EX: Colorado Potato Beetle (CPB) feed on potatoes, plants die, and the CPB can’t survive in the winter above ground. The CPB go to the forests and go into the leaf litter. This is a short migration. CPB overwinter as adults; they have digested muscles to survive over winter. They have to feed and crawl out enmass toward the potatoes. People dig trenches and fill up with kerosene burn them. b. Migrate to a climatically DIFFERENT region that isn’t ―too far‖ away i. Ex: Lady bird beetles—in CA—can’t diapause in trees. Lady Bird Beetles fly significant distances from low lying areas in valleys to higher places in the mountains to diapause . Happily eating aphids in the summer, then move up mountain in the winter. They aggregate by pheromones. Then there are enormous clusters of lady bird beetles. When it gets warm, they fly back to the lowlands. If you buy them, they won’t stay. They are physiologically PROGRAMED to fly away. c. Migrate long distances i. Typically reproductive adults not interested in mating. ii. Going to an area where the weather is the same as the place where they were born. (?) iii. EX: Monarchs in CA with 38 overwintering sites which gathers from the west of the Rockies. Eastern N.A. monarchs migrate to 10 spots in Mexico in the Halesco and Zapatisca iv. They migrate back in early spring/summer when the photoperiod is correct from CA. The Mexican monarchs migrate back and lay eggs on milkweed 25 in southern states. Monarchs in the East take multiple generations to migrate. Adults migrate 2,500 miles from the NE of America to Mexico. Then they come back and lay eggs in the south. The milkweeds help track monarchs. Found plant compounds typical of the south in Monarchs found in the north and visaversa. No one individual makes the entire migration from NH to Mexico and back. Competition in Mexico prevents them all from staying in Mexico. Mosquitoes fly significant distances—17 miles for migrating—in CA. Will fly some distance from the rice fields to diapause. They move to avoid flooding. d. END OF INFO FOR EXAM MONDAY October 27, 2003 NOTES: Insect Development and Evolution (2003) by Bruce Heming The Insects by Chapman—broader and easier to read---good physiology and morphology of insects Review Question given out Feeding Behavior Phytophagous—feed on LIVING plants Gustation Phagostimulants a. Total species: green plants 22%, Phytophagous Insects 26%, Other insects 31%, Verts 4%, Protozoa 2%, other inverts 15%, b. Why plants? Can’t move but have defensive compounds c. Cellulose, Hemicellulose: sugar polymer indigestible—must have gut flora d. Lignin: Binds with proteins and carbs, Tannins: Binds with proteins, So both are poisons e. 2ndary plant compounds: POISONS—alkaloids, toxic amino acids, cyangens, gluucosinolates, proteinase inhibitors f. Example: Trees loose 26-53% of the total leaf surface consumed—total consumption—27%. Cycads have very high levels of poisons and developed early evolutionarily. g. Predator pressure on plants Insects are >50% protein dry weight 7-14% Nitrogen dry weight 26 Plants are protein dry weight 0.5-8% Nitrogen dry weight Plants are most succulent and most protein and nitrogen at leaf-out. This is when they are most nutritious at that point. As they age, they have more poisons. EXAMPLE Oak: bud burst: 5% Nitrogen dry weight Leaf expanded 2.5% Nitrogen dry weight Late Season 1.5% Nitrogen dry weight Insect Feeding Guilds h. Chewers: chew food i. Miners and borers: feed on inside moist succulent tissues and protected from predators and parasites—clear pictures of miners that go into the mesophyll instead of the exterior surface of leaf. The clue is blotching or discoloration of leaf. Can often identify species depending on colors/lines on leaves. j. Gall formers: feed inside plant tissues and egg is laid and hatches. Then when the organism hatches, the plant develops abnormally. This is a gall: i. Wasps, flies, aphids and chew their way out when adult k. Sucking insects: Homoptera and Heteroptera/Hemiptera: True bugs and Thrips feeding on the phloem—high proteins and carbohydrates. Really only parasites since they aren’t killing the plants i. To get the amount of nitrogen they need, they eat a lot of this sap. The midgut has a long tube. To extract the maximum of nitrogen, there is a loop in the tube that facilitates movement of water out of the loop. Water comes out, and goes into the end of the tube. They pee out sugar water constantly. Bees and wasps and flies come into eat this. ii. The plant turns black and there is sooty mold growing there. iii. Pear trees have psyllids which debilitate the tree. Wasps would buzz around the tree. l. Seed eaters: Beetles—family Bruchidae—True plant predator: eating the babies. Seeds are high in proteins. 2. Predaceous—feeding on LIVING animals (includes parasites) 3. Saphrophagous—Feed on NON-LIVING plant and animal material—fungi and goober bacteria are the nutrients. Living tissue is eaten by screw worms. 4. Mycetophagous—eat primarily on fungus—which get lumped with plants 5. Omnivores—eat it all 6. Aphagy—adults that don’t eat anything—special not looked at often Friday, October 31, 2003 Predators: Odonata, Neuroptera, Beetles, Bugs, Flies, Wasps Predators kill the prey rapidly, devour multiple prey, and often are larger than the prey. Both adults and immatures can be predatory. Non-reflexing—one time entry of digestive juices into the prey Reflexing—neuropterasend the digestive juices into the prey over and over, injecting and sucking out digestive juices. Parasites: Live on larger hosts, usually weaken but rarely kill host, often many individuals on one host. May be ecto or endo parasites Ectoparasites: lice, flies, sheepkeds, bot flies Endoparasites: few insects are endoparasites: Bot flies and Blow flies 27 There are temporary and permanent parasites. Parasitoids: only 1 host is required for development. Parasitoid is slightly to much smaller than host. The immature is a parasite and the adult has a different lifestyle. Mostly these are wasps or some flies. 1. The adult female lays eggs on the prey item 2. Eggs hatch and the larva develop in the host. Viruses and other compounds are used to take over the host. 3. Hatch from the host and the host dies. a. Ex: tomato plants are infested has tomato or tobacco hornworms which look normal b. Then white cocoons hatch out which are multiple embryos from a single egg. c. Doesn’t consume the most critical organs and suppresses the JH. d. Gnaws out of caterpillar and escapes from cocoon so the host is dead. 4. Kills Host as immature and FREE LIVING as adult. This controls the insects. Hyperparasitoids—parasites on parasites. There are examples, but not known. Won’t lay egg on scale if Quelyea. Black scale has 2 parasites: Metaphyus lounsboryi and Scutellista cynea are Encyrtidae Superparasitism—parasite on parasite on parasite. Mycophagy –groups of specialized insects with pouches, mycongia, chew a hole in the tree Spores are brought into tree in the mycongia and the spores then germinate Insect grows and eats the food from the spores that germinated. Dutch Elm beetles Beetles are natives as are the trees and from Holland Finding Food: How is it done? 1. Visually a. Form i. Ladybird beetles and Grasshoppers respond to the form of vertical lines from a Y-shaped branch. b. Color i. Some phytophagous groups only see one color of yellow to green (550 nm) since this is the yellow color of young, actively growing vegetation. ii. Most insects don’t see red. iii. Often it is the ultra-violet colors that attract bugs. c. Movement i. Dark black or brown object that move are most attractive ii. Tsetse flies attracted to dark moving objects such as cars. These flies are rare but will transmit disease. 2. Chemical Means a. Taste and Smell i. Must have an attractive odor or taste. ii. Must NOT have disagreeable odor or taste iii. Sensing structures are in the tarsi with additional ones in the mouth iv. Odors are used to see if parasites are already there. v. Contact chemoreceptors can tell the levels of sugars, carbos, etc. b. TASTE: Final step: does it taste nutritious? 28 i. Must be level of acceptable food ii. This indicates phagostimulants 1. Primary plant compounds: sugars, proteins have a direct value that is a feeding stimulant 2. Secondary plant compounds These are cues or triggers but not of a nutritional value. This is a ―token simuli‖ 3. Ex: Alkaloids, cyanogens, turpines are used as cues. c. EXAMPLES Crucifers-cabbage and spinach—have sinigrin which is mostly poisonous. This is used as a cue to them to eat or not eat. d. Cucurbits: cucumbers have cucurbitin which is a strong odor in leaves and is a poison to most except for a few that use odor to find it. e. Cotton has COSSYPOL??????? i. Plant breeders take out poison but not a good idea. The cucumber beetle in KS eats seeds and plants transmitting the bacteria wilt. Answer: Make cucumber without cucurbit, however, then MANY OTHER organisms eat the cucumber. Monday November 3, 2003 Communication: Sound: obvious production from some grasshoppers, cicadas: 6 orders have the ability to produce and hear sound. Some sounds are outside human hearing. Sounds are produced and transmitted through air, water, solids. Intraspecific sounds for mating behavior and territoriality. EX: Cricket sounds attracts mate and keep other males away Sounds are easily heard and transmitted a long way. Water sounds transmit predator/prey sounds EX: Whirlygig beetles sense the vibration on water so they have specialized structures to make sounds EX: Mosquitoes have the attractive whine of the wing for males to find females. The male antennae is long and feathery. EX: Orthoptera wing has a curved row of teeth: called the file which moves across the scraper. These are on both wings and the file strums back and forth over the scraper of the other wing. EX: Grasshopper legs have pegs that move agains the wing to make noise. This is called STRIDULATION: movement of hardened ridges of file across the scraper. Tymbals: convex curved scleratized surface with a muscle that moves to make noise. EX: Cicada has a tymbal on the abdomen with a space below the convex curve that is pulled down and amplifies noise. Percussion: solid surfaces are struck to make noise. Body parts are struck against some substrate. EX: termites—bang their head on the tunnel EX: green lacewings—tap abdomen on plants and we can’t hear it. This has been used to possibly determine species. SIGHT AS COMMUNICATION Visual cues are used for mating and this can be dancing, color, and form. There are colors, polarized lights, and movements to signal something visually. Biolumenescence exists in a wide variety of organisms. Insects that have this characteristics wouuld be Colllembula, Homoptera in the tropics, Beetles:fireflies 29 New Zealand: mycetophilids Australia: sciarids Larva produce strings of slimy, gunky silk. Light attracts other organisms to the gunk, they get stuck, and the larva eats them. Lampyridae: fireflies have luciferin: this produces light. The enzyme luciferase allows a 98% transfer of energy to light. This means 98% of the luciferase is turned into luciferin and therefore light. Species specific patterns are typically produced by males. The females are attracted to it. Sometimes this is opposite. EX: Males produce a light in a cycle to attract the Female. After mating, the females change flash pattern to attract the males of other species and eat them. OLFACTORY COMMUNICATION Extremely common and are important in all investigated organisms. 1. Pheromones: act between individuals of the same species. Chemicals are produced. a. Sex pheromones: facilitate mating. The female gives off an odor in addition to sights and sounds. The smell confirms that this is a female of the same species. i. Glands at the apex of the abdomen have special setae ii. Lepidoptera males also have pheromone antennae. There are ceoloconic pegs to detect even 1 molecule of pheromone. This is a plate on the antennae. iii. Effort is put into producing pheromone, molecules that are species specific for monitoring iv. Developing lures to monitor pest species 1. Cotton and other crops are flooded with pheromones to confuse the males. However, this is EXPENSIVE! b. Aggregation pheromones: California lady bird beetles diapause and give off the pheromone to gather in the same location. Leptoglysi occidentalis is leaf footed bug that feeds on conifer cones and has spread to the east coast. When they find something good, they give off the aggregation pheromones to attract more. c. Food resources, Bark beetles, scolytid beetles go to a dead/dying tree so it is the conifer that attracts more bugs Conifers have pitch and the beetles bore into it. Pitch covers the hole. If enough beetles attack the tree, it is killed. Other smells: Trail markers: ants have Dufours glands. The dab abdomen on ground and leave the trail. This trail can LAST! EX: Black carpenter ants can follow a trail from the year before. Only bleach or something extremely tough can get rid of the trail. c. Alarm pheromones: behavior wasps/bees will ignore you until you disturb them. Then they sting. As they sting and give off odor to attract more sting, sting, sting, sting. 2. Allelochemicals—as opposed to pheromones—between species communications a. Allomones:advantagous to producers b. Kairomones: advantagous to reciever Wednesday November 5, 2003 Medical Entomology Disease dynamics-hosts-carriers of disease 30 Need to examine humans for susceptibility, habitat of host, natural history, habits, asympotomatic resevoirs—hosts with natural resistance Pathogen/parasite Need to know life cycle, pathogenicity, persistence, specificity Vectors Serves to transfer pathogen from one host to another Need to know biology, ecology, life cycles, population dynamics, and distribution Resevoir: Need to know diversity-more than one—natural history, habitat, suitability Human Diseases in reservoirs referred to as ZOONOSES,that are normally in animals, natural parasite/pathogen of an animal which can be transmitted to humans, extremely difficult to erradicate: Insects of medical importance 1. Entomphobia: Delusory parasitosis: insane fear of insects 2. Annoyance/blood loss 3. Accidental injury to sense organs 4. Envenomization 5. Dermatosis:skin irritation 6. Myiasis-invasion of organs & tissues (diptera) 7. Allergies Evolution of parasitism Ecto vs endoparasites Ectoparasites cause the most problems: true bugs, flies, lice, ticks, fleas 1. Association with animals in nests, burrows-insects could act as scavengers, predating on other arthropods 2. Mouthparts are adapted for fluid feeding a. Blood is a poor food source, but it does have a high number of proteins which is necessary of egg development b. Insects have gut symbionts which provide nutrients that are not acquired from blood. c. Energy for flight comes from COOH—aquire from plants (honeydew, nectar) Definition: An organic compound containing the COOH functional group. Examples: An example is acetic acid, CH3COOH d. In nests and caves: bedbugs, lice, fly larvae e. Burrows: sand flies, fleas, lice 3. Evolutionary trends in blood feeder: female only, on the host for minutes at a time: mosquito, black fly. a. Male & Female: stable and tsetse flies b. Adults feed on blood and stay on host: fleas c. Larva only: Congofloor maggot d. Larva and adults:bedbugs do intermittant feeding e. Permanent: fleas & lice f. Occasional/opportunistic: diptera feed on animal wounds Endoparasites are diptera (myiasis) 1. Sarcophagidae: flesh fly—feed on dung, dead bodies, egg pods Some endoparasites on humans: wohlfahrtia Also screw worm, blowfly, botfly 2. Host-seeking/location by bloodfeeding insects:phytophagous 31 Monday November 10, 2003 Host-seeking/location by blood feeding insects (arthropods) Males are phytophagous—scavenger larvae Adults of both sexes feed on COOH after they emerge. Females then need protein, blood, necessary to mature a batch of eggs Female must have a long distance attraction to find the host by 1. Host Movement 2. CO2 is continually given off by vertebrates. Gas that radiates out from host a. Depending on wind currents/host movements, the carbon dioxide moves out b. A large plume of CO2 is created. Highly concentrated near the host. c. CO2 dissipates so it doesn’t attract female d. Sense organ in female on her antennae picks up CO 2 i. This changes her behavior from random to directed movement upwind in plume ii. As female flies, CO 2 concentration increases. Female moves in and out of plume until CO 2 concentration grows stronger. e. In the atmosphere, CO 2 concentration is 0.03%, stronger from humans. f. Mosquito female is on/near the host i. Three important things from warm blooded mammals that signal females to land: 1. HEAT (KEY) 2. Chemicals that volatilize from the skin (FATTY ACIDS) KEY 3. Moisture (KEY) 4. CO2 ( ii. Sensory receptors sense these things and heating blood is most important g.Mosquito lands i. Explores the host—long or short/immediate response ii. Depends on the FATTY ACIDS in combination with other factors iii. Walks around, testing surface of skin. Some don’t bite & fly off iv. If host is good—Biting is initiated v. Sensory structures on the tarsi—ceoloconic sensors h.Mosquito starts to bite i. Blade like mandibles and maxiliae to pierce skin ii. 1 of 2 things happens—pulls out or mouth parts search for capillary iii. Tip of labium or maxillary palpi—have sensors 1. labrum epipharynx that searches for capillary under skin 2. Slides into capillary which is fine and doesn’t allow bleeding 3. Puts in anticoagulants and lubricants into blood a. Protenaceous—create reaction 4. labrum epipharynx forms a tube and sucks out blood and uses pharyngeal pump to take out blood. 5. There are features of blood to cause the female to pull out iv. Won’t eat more than can hold—have stretch receptors that terminate feeding when full v. Flies away with blood meal i. Land equally but differing skin chemistry effects how many bites one person will get over another person. j. Deer flies buzz around head with no warning i. Driving you batty, then gone. This happens over and over ii. High Visual component to host seeking. Color and movement KEY to landing of Deer Fly—SHINY BLACK is very attractive to Deer & Horse flies 32 iii. Deer flies have a perching spot in the woods. We can’t explain why they disappear 3. How do we prevent them from Biting? a. We use the Repellent DEET—really a ―Hident‖ i. Mosquitoes not landing on you ii. DEET clogs up sense organs on the tarsi 1. molecule fits into coeloconic opening and blocks scent from you. 2. After 3-4 hours, mosquitoes land on you again because smell coming through. 4. Some mosquitoes are host specificsometimes only one type of host a. Birds, generally not just one species b. Frogs—one species in NH that only feeds on frogs—Ranavore. It is the sound of the frogs that attracts them 5. One species of black fly that feeds only on 1 species of bird a. Common Loon—Specifically attracted to gland by tail—Uropygial gland that produces water repellent substance for loon. b. Very rare existence Insects of Medical Importance Hemipetera Two families: Cimidae (Bedbugs)vast majority feed on bats. A few feed on birds-swallows, chickens, humans 1. Entire family is ectoparasitic. Characteristics: Wingless, nocturnal, flattened bodies to fit into cracks and crevices, feed on blood. 2. Gradual metamorphosis, incomplete, all stages after egg feed on blood. 3. 3 Human bedbug: Cimex lectularius lives in cool climates C. hemipterus—tropical Leptocimex boueti—live in Africa, in mud, recent human parasite. a. Evolution—lived in caves, humans were there and so the bed bugs migrated from bats to humans. b. Humans can bring in bedbugs from attics. ―Nest parasites‖—associated with roosts or nests of host. When swallows go away, bed bugs survive without feeding for a year or more. Go into dormancy of some sort—diapause or other sort. MEDICAL IMPORTANCE: allergies with itchy swelling and gradually develops over time for humans. May not know you have a bed bug problem. NO DISEASES known to be transmitted by bedbugs. Hemolymph of bedbugs is acidic and poor host for microorganisms. Recent resurgence of bedbugs in the US—cities Tell tale signs—sickenly sweet smell, fecal material around where they live, see them when you flick on the light at night. Reduviidae—Cone nose bugs, (assassin bugs—whole family is like this) Triatominae—feed on animals—mammalian hosts. Painless bites. These are an inch or more long. They give a sharp jab without anesthetic that makes it painless. Chagas’ Disease: named after Carlos Chagas—investigated it in 1909. Caused by a protest: Trypanosoma cruzi—live in hindgut of bugs and described as posterior station parasite. Transmission: Disease is transmitted by feces, not by the bite of bug. Bugs defecate almost immediately after feeding. Bug defecates where the bite was. The bug turns around after biting and defecates on bite. No good explanation exists for why the bugs turn around. Two things prevent transmission of Chagas disease in the southern US: 33 1.More painful bite that makes you stop the bite. 2. They don’t turn around and defecate. Symptoms: Chronic heart problems. 1. Swelling called chagoma. Occurs on the face where the pathogen was rubbed into mucus membranes, eyes, ect. 2. Cardiac lesions that are chronic. Weakening of the heart muscles which leads to heart failure. 3. Trans-placental—can be transmitted from mother to baby. Prognosis—not so good because these bugs can feed on over 150 hosts. There are a few preferred hosts, but can be on others. Hosts can be wild armadillos or domestic animals. Or even ―peridomestic‖—hang around dwellings but occasionally live around humansRaccoons, opossums Multiple cycles—wild, domestic, bug to dog to human, bug to mice to humans, mice to dogs when dogs eat the rat/mice. Dogs wander out in the wild. Bring home disease and the bugs in the house feed on dogs and then the bugs feed on humans. No advantage to bug to have the protista. A home was sampled for Panstrongylus There were 529 bugs in this house in Argentina. There were 225 bugs in the living room. Of those, 10% were infected with Chagas disease. 93% of theses bugs had fed on chickens that roosted in the living room. In the bed room, there were 304 bugs of which 56% were infected and 82% fed on humans. Why so complicated? Too many hosts, cycles, complex cycles so control is IMPOSSIBLE! Primary control would be to construct houses that won’t allow bugs to live there. Diagnosis of disease is poor. Do a Xenodiagnosis—feed clean bug on human. If bug gets infected, then the human is infected. Many humans are asymptomatic for the disease. So many wild ―reservoirs‖ that hold this disease. This disease can be a long-term chronic disease of 30 years that can be transmitted by blood or from mother to baby. Made worse by people migrating to rainforest and get into the wild cycle. Also a tremendous issue in urban slums where people come together from the rural areas in the last 20 years around urban centers. Treatment—there are some drugs that are ineffective and very toxic. Chronic infections are the rule. Only 1% of infected people have overt symptoms. Most people can’t afford better houses or treatments. Order: Phthiraptera—Lice—biting/chewing lice (Suborder: Mallophaga) eat blood of birds and sucking lice (Suborder: Anoplura) eat blood of mammals 500 species of sucking lice. Mammal parasites. Ectoparasites that are small, dorsallyventrally flattened. Highly modified legs to grab onto hairs of host. Tarsi are modified to grab. Mostly live permanently on host. Sometimes they live on nest. Human Lice: Transmitted by physical contact; generally not transmitted by clothing since they can’t live away from the host. Clothing or Body Louse—medically important. Hides and lays eggs in the seams of clothing. Most common in people who don’t change clothes. Nick names:cooties, seam squirrels, grey backs. Can transmit disease Head Louse-don’t transmit disease. Lives on edges of hair head. Eggs cemented to hair shaft. A MAJOR PROBLEM—have developed resistance to chemicals. Psychologically damaging but no long term damage. Hygiene not a factor. Pubic Louse- don’t transmit disease There are closely related species on other primates. 1. Epidemic Typhus—Most common in Africa, Asia, Cent & S. America i. Rickettsia prowezekii 34 ii. Outbreaks not so common. WWI—6-7 million deaths in Russia iii. Periodic outbreaks of war—instability and breakdown of sanitation iv. Still out there and conditions still allow for outbreaks v. Ethiopia sheep are reservoir, as are flying squirrels. 2. Trench Fever—associated with war a. Just feel bad b. Transmitted by feces or inhaling by aerosol 3. Epidemic relapsing fever a. Borrelia—in the louse and scratching will rub organism into skin. The borrelia congregate in louse legs. Siphonaptera—fleas 1. Plague—larvae feed on feces of adult fleas. Live in nest of host to hop on and off. Scavengers and highly modified adults that are wingless and laterally flattened. a. Cat flea—more common on dog flea b. Dog Flea—less common and in the Southern US. Difficult to exterminate and live without feed for a long time—maybe up to a year. Then they sense the heat or infared Less common due to chemicals that go on the animalsFRONTLINE, ADVANTAGE Bubonic Plague caused by Yersinia pestis and transmitted by flea, sometimes human flea: Pulex irriatans. Also transmitted by Oriental Rat Flea, Xenopsylla cheopis. A zooanopsis that is not usually in humans. Originated in wild rodents, gerbils, in China. Disease was cycling between rodents and host fleas in nests. When people showed up, they picked up the disease In mid gut of flea, the plague bacillae blocks the intestines. The flea is hungry, and feeds like mad, but can’t get food due to blockage. The pharyngal pump moves the blood back and forth which in turn breaks off part of the bacillae blockage. THIS IS GREAT TRANSMISSION. A high blockage index is the key for transmission. Oriental Rat Fleas have a high index. Historical perspective: In the medieval times, human populations increased due to warm weather. Crop yields were good and ―living easy‖. In 1100’s humans didn’t do so well. Europeans were introduced to Asian fleas from rats from ships. Fourth and current pandemic occurred in 1860’s. CURRENTLY: Plague in San Francisco in 1906 and established in Prairie Dogs. IT STILL EXISTS. Periodically Epizoodics that prairie dogs die off and humans get involved. Sylvatic Plague: in the countryside and not infecting humans often. 10-40 cases of bubonic plague every year. Few deaths because it is cared for by antibiotics which must start early for success in cure. Larger outbreaks of course if there is war. Kills by shutting down immune system. Causes lesions on organs and internal hemorrhaging. The black death part comes from hemmoraging in the liver. Bubos are lesions on humans. Numonic plague spreads among people. This is really bad. 3. Murine typhus Monday November 17, 2003 Sand Flies—(Plebotomidae/inae) Moth flies-Psycodidae—drain flies 35 500 species world wide Genus Old world: Plebotomus Genus New world: Lutzomyia Small, weak flying blood sucking. In diurnal species, they live in the dark forests. Live in :Caves, animal burrows, hollows in trees, holes in trees. Feed on hosts and occur in the tropics or subtropics in places with high humidity. Diseases: MAIN DISEASE: Leishmaniasis—really caused by many different of protozoan parasites related to trypanozomes. Stay in a lepotomonad form—missing some sort of extension. Epidemiology: 2 forms: 1. Visceral: general infection in many internal organs that then shut down and person dies. 2. Dermal: Skin infection that cause lesions and does not effect internal organs. Both forms occur everywhere. Lesions can be pimples or open sores oozing puss. EX: Muco Cutaneous Leishmanaisis eats away face but not fatal. The secondary infections are fatal. Dry—crusty, dry lesions Wet –oozy, pussy lesions The main problem: ―SO DAMN COMPLICATED!‖ VERY COMPLICATED Breif explanation of reservoirs: Rodents: Gerbils thought that the disease originated when nomadic people came into contact with gerbils. Urban cycle: Disease circles from humans to sand flies back and forth. Wild cycle: Wild animal to sand flies and back Dog cycle: Dog goes to the wild area, gets the sand flies and parasites. Then the Dog returns home and brings the disease home. Or the other way. Dogs are Liaison Carriers Sand Fly Fever—non fatal but debiliating. Carrion’s disease—mild but nasty Various drugs have been used but not to complete eradication. Black Flies (Simuliidae) Over 2000 species. Morphospecies have a complex of species—maybe more than 7 different genetically, non-breeding, but from the outside they look identical. Look at chromosomes to determine differences—polytine chromosomes Can’t look at adult chromosomes. Need the salivary glands of the larvae to identify. Why is that important? How many are actually the vector? 6 distinct species but only one is the vector. NOT EASY TO KNOW ONCHOCERCIASIS (River Blindness) Larvae live in runny water only. In streams, larlge or small. Larvae are filter feeders. Orient themselves to filter water column. Larvae pupate under water and the coccoon stays underwater. Adult rides bubble of air to surface. Then they go to edge of stream, harden exoskeleton. They then fly 20 miles by self or are carried up to 200 miles by wind. Feed on birds or humans. This is the one that only lives on loons. Females trail legs in water and pick up traces of europigial oil to loon host. Monetary problem: Black fly can be so abundant they bit the cattle and cause anphylactic shock. Hundreds or thousands of cattle died in the 1920-1930’s Cnephia pecuarum—occurred in HUGE numbers in the Mississippi River and tributaries. They were so abundant that humans, pigs, cows died. Eliminated from rivers by decline in water quality. Only 2 breeding populations in tributaries of the Arkansas river. Disease transmitted by falarial parasitic worm: Onchocera volvulus. In falarial nematodes: immature stage: microfilaria laid by adults, picked up by black flies and transmitted to other host. The microfilariae ciruculate in blood stream and 36 then picked up by black fly. Go through 2 molts in gut of black fly to L3 stage. Here they are transmitted to human and migrate as L4 and then goes to adult Location: East & West Africa, Cent. & South America. West Africa: Open, non-forested areas, disease is wide spread. In Cent. & South America, East Africa found in small forested areas. Many small foci. Why? Because of local vector habits and particular black fly secies. How did it get to central and south America—Slave Trade. Symptoms: Invade lymph nodes and lymphatic system and cause swell Cause dermal irritation. Microfilariae congregate in the eyes causing cloudy vision or blindness in West Africa. 10-15% of those infected in Africa are blinded. Treatment: Drugs weren’t effective until now. Old chemical: DEC—kills microfilaria but when microfilaria die, they break down and release foreign proteins and there are severe side-effects. Ivermectin is used to treat this one and HEART WORM. It is an effective treatment. WHO developed a project to treat streams to eliminate this disease in 92% of the area. People have returned and been able to harvest/farm. 17-18 million infected at any given time and not increasing. 16.8 million infected people in Africa—mostly East Africa. Resistance is worrisome but the rate of blindness has been reduced. Isolated focus in Yemen. There are a few streams there. Wednesday, November 19, 2003 Malaria Mosquitoes (cuclidae). Eggs laid in standing water Anapheles—over 400 sp, but only 15% are major vector of the disease Factors for transmission (1) Must be anthropophilic—like people Endophily—can get into dwellings easily and will digest blood meal there, feeding during the night Others are zoophilic—not efficient vectors of transmitting Maleria since they don’t prefer to feed on people. (2) Parasites: 4 human ones in the genus Plasmodium vivax, P. ovale, P. malariae, P. falciparum. LOOK AT HANDOUT! Malaria parasites: primate, birds, reptiles. Malaria is a varied group of diseases. Primary bird vector in genus Culex since they are bird-philic Primary reptile vector in genus Aedes (3) Reservoirs:Humans who have gotten over or not injured by parasite (4) Temperature (5) Temperature/Humidity—favors longevity (6) Suitable Breeding sites for mosquitoes (vectors) (7) Precipitation/ Irrigation—creates Mostquito habitat (8) DROUGHT—new areas of standing water in streams that dry up. Has been documented in Sri Lanka What about areas with Anopheles without Malaria? --Lack of effective vectors. Some species don’t maintain parasite --Low Density of vectors. --Lack of carriers—not infected humans, if parasite is eliminated. This is what happened in US. Kept getting rid of people. Concentrations of people from other areas can increase the disease. Everyone treated, no parasite even if you have the mosquito 37 --Climate limits the parasite would be in areas where at some point in the year goes below freezing. --Immunity on the part of humans --Lack of contact Disease discriptions: Disease characteristics develops within 24-72 hours depending on parasite Paroxyms—shaking—72 hours apart—beginning of 4th day—―Quartan‖ 48 hours apart—beginning of 3rd day—―Tertian‖ Four stages of disease: 1. Quiet stage: Body temp normal. Parasite developing in RBCs 2. Cold/Chill stage: Body temp spikes to 104, release of parasite from RBC. Immune system reacting to the simultaneous release of other immune response triggers. This is an anaphalactic reaction. Hot Stage—at the hot temp, 104 degrees, Sweating Stage—need to cool off so you sweat. Do this every 3 days for months. Break out of blood cells that are injested by mosquito. Mosquito is the Definite Host—have the sexually mature parasite. Intermediate Host—humans—non-reproductive stage. Parasite squeezes through midgut and transforms into the infective form of sporozoite that migrates into salivary glands. Then the biting mosquito injects into humans. Complicated System Control: Mosquitoes and parasites. Mosquito control used to work well. Cover wall with DDT and the endophylic mosquitoes. Worked well for a year. It doesn’t work so well now. People die but DDT might work as a control. Drug for humans: Quinine, synthetic quinine derivatives. Used to treat malaria and the symptoms. Some areas are resisitant to the parasite. Even drugs you take to prevent malaria don’t work anymore (propahlatic drug) Falcip maliaria is resistant to drug and causes blood cells together. Children die. What about sickle cell anemia? November 21, 2003—YELLOW FEVER! Urban Yellow Fever is well known 1860’s 13,000 people died Philadelphia—4,000 Species: Aedes aegypti feeds on humans and breeds prolifically in small containers—rain barrels, urns in cemetaries. Bright silver markings with purple scales. Common in the SE— and in Arizona before the water went onto become intermittent. Was gone from the US for a while. Now it has filtered back to Tucson. Jungle Yellow Fever Different from urban fever—transmitted by mosquitoes that live in forest canopies. Various parts of the world still have outbreaks. Thought to have origninated in Africa with a cycle between mosquitoes and monkeys. Viremia—six day period when the mosquitoes get infected. Mortality is 40% 1st stage—High fever, nausea, vomitiing a nd joint pain 2nd stage—hemoraging of internal organs, liver pathology, liver releases pigments called belarumens—skin turns yellow and causes jaundice (very bad) Epidemiology of yellow fever: Established in natural, wild, cycles makes eradication IMPOSSIBLE IN AFRICA: The virus does this: MonkeysMosquitoesMonkeys 38 When forests are cleared, ―false bananas‖ are planted in plantations by humans. A species of mosquito Aedes bromeliae and grow in the axil of the bromeliads. Feed on monkeys that were infected in the forest. Then these mosquitoes get infected. Monkey Aedes bromeliaeHumans Aedes egyptiHumans This is a ―peridomes‖ cycle that takes virus from wild area to city IN NEW WORLD: Brought over in water barrels during the slave trade. New outbreaks occurred and confused people in 1932 in Brazil. Haemagogus sabethes is the New World mosquito that somehow got to the wild monkeys. The mosquitoes ONLY live up in the canopy until trees are cut down. Haemagogus sabethesMonkeys Haemagogus sabetheshumansAeges eqyptiHumans Dark form of Aedes aegypti doesn’t feed on humans and stays in tree holes Light form of Aedes aegypti does feed on humans and lives in fake water containers. TREATMENT: Vaccine is good but doesn’t get to where it needs to go Can treat the symptoms of the virus, but only if caught early. OUTLOOK: Not good. So much virus cirulation still going on and on. Still periodic outbreaks. Politicians: 1987, Nigeria, 40,000 infected, 22,000 dead. Nigeria reported 1500 cases. It is estimated that there are 50 cases for every case reported. Monkeys in Africa don’t die from it Monkeys in the New World DIE from infection. This means it was introduced to the new world and developed in Africa ANOTHER NASTY VIRUS: Dengue Group: 4 distinct serotypes1-4 Caused ―Breakbone Fever‖ because there is EXCRUCIATING pain in the muscles and feels like your bones are breaking Widespread in Asia and Caribbean but there are scattered outbreaks that are focused in other places. Spread by Aedes aegypti in the new world and spread by Aedes aegypti and others in the old world This started out as a wild jungle cycle. 1977--2,000 cases Serotype 1 in Puerto Rico, 1978—4,000 cases Serotype 1 in Puerto Rico, Serotypes 3&4 are the particularlly deadly ones. They cause ―Dengue hemorrhagic fever‖ Hemorraging in joints, near the surface of the skin. NO VACCINE! Ae. Albopictus—Asian Tiger Mosquito—most abundent in the SE and MAIN vector of Dengue. Likes to breed in tires. Canopy dwelling monkeys, humans go out to forest, bring back to rural dwellings. Ae. Albopictus picks up virus from human and transmits the disease to humans. Cylces in the Caribbean, and can easily come to the US. Not much you can do to erradicate this disease Lymphatic Filariasis—caused by nematodes. 3 species involved. 1. Wuchereria bancroftIi—90% of cases 2. Brugia malayi—10% 3. Brugia timori—restricted to Timor Parasite causes the elephantitis in the lower trunk. Ex: Man wheeling scrotum in wheelbarrow. Swelling comes from lymph system being blocked and liquids building up behind blockage. Most often occurs in lower body parts. Two forms of disease: 39 periodic form: nocturnally active and come to the capillaries at night and migrate back into the body during the day. They go somewhere in the interior parts of the lymph system. It is a complex reaction that is not well understood. Supbperiodic form diurnal Periodic Periodic Subperiodic Origin To IndiaAfricaby Started in SE Asia by Pacific Island culex then to China S. America by Slave Ships and Japan Culex anopheles Culex Aedes polynesiensis Vector Time frame Night time Night Time No peak—or day and night because the vector is day biter. Generalized Life Cycle of the parasite: Mf (microfilaria) circulating in human mosquito injests from humanMF physically penetrates the gut wall of the mosquitoMF migrates to thorasic musclestransforms to ―sausage‖ stageundergoes two moltsL3 stage is the infective stage and migrates to the proboscis and migrates through proboscis to the bite woundmigrates to the lymph system of the new host and mature there. Above cycle is for Wuchereria bancroftIi and does not go to animals. The other one, Brugia malayi, is a zoonosis and will use other animals as a reservoir. Adults can live up to 10 years in the host. Outlook: Poor, human mortality low, a chronic disease. 40 Daily variations in Periodic and Subperiodic Lymphatic filariasis 30 Daytime 25 Diurnal Mosquito Nighttime Number of organisms 20 Nocturnal MF 15 Nocuturnal Mosquito 10 Diurnal MF 5 0 10 15 20 25 30 Time Viral Encephalitis: EEE: Eastern SLE: St. Louis WE: Western 260 Arboviruses: arthropod borne viruses COMPLEX: I. Virus survies mosquito and vertebrate host II. Mosquitoes have enzootic cycle III. Mosquitoes feed on a variety of hosts IV. Vertebrates must be capable of amplifying the virus WNV: West Nile Virus Must have the following to have an infection: (1) Virus must amplify in the vertebrate, usually a bird (2) Reservoir population size, such as birds, amplifies virus well (3) Pool of suseptible host that haven’t been infected before (4) Climatic factors that effect the size of the vector population (5) Vector abundance in August Questions—when does the virus circulate in the vertebrate population? Determine by a sentinel system—check on animals to determine who much virus is circulating. Need to determine if an outbreak will occur or not. Can be used to determine outbreaks. In 1974—pheasants and horses died. Birds transmitted the EEE virus by pecking. Mortality in humans for EEE is 80% but doesn’t occur often in humans. 41 Encephalitis is swelling of the brain and can cause permanent disability. Unfortunately can cause issues. Old people, immune system compromised people, & pregnant woman causes very serious problems for babies that survive. St. Louishigh mortality rates in horses. Horses and Humans are Dead end hosts for all but St. Louis. Mosquitoes can’t get virus from humans or horses. West Nile appeared in US in 1999 in Queens/Long Island. First isolated in West Africa in the 1930’s. No one knows how it got here. 1. Spread like crazy all over the country 2. In a large variety of birds. Some birds like crows are very suseptible. 1000 humans in Colorado this year and 100 in 2002. 3. Biggest outbreaks are out west. In the east virus is in birds and Culex; Eastern Culex don’t bite humans. In the west and south, Culex tarsalis will bite humans. Eastern infections in humans happens from other mosquitoes. Probably by Aedes and does do well in them. Wednesday November 26, 2003 Tsetse Fly—Glossina now Afrotropical and fossils occur in Colorado Another one in DC. Florascant Shales—Plioecene Occur now in Africa in: 1. Riverine areas in the vegetation—transmit Gambian Rhodesian SS 2. Savanah species—transmit Rhodesian SS Both male and female feed on blood. Females have live birth of mature immatures that are ready to pupate Gambian Sleeping Sickness---TsetseHumansTsetse now. Used to include other animal hosts but no longer How? Trypanosome ciruclates in blood for a long time. When the parasite accumulate in the cerebrospinal fluid, the human shows the symptoms: drowsiness, sleepiness, death occurs when a coma happens. Time frame: 2 years or more. This means humans are a good source for uninfected flies to pick up disease. Rhodesian SS Zoonosis with ungulate animals which aren’t affected by trypanosome. UngulateTsetse flyHuman Time frame: death in 6 months or so. This indicates that the parasite is not as well adapted to the human, a more recent interaction. How to eliminate: Get rid of trees around riverine area, even tearing up the ground. There are parasites of tsetse flies. Insectacides for spraying areas and is practical for the riverine tsetse flies. NOT so with the savanna species you can’t spray. 42 Selected removal of hosts which are the ungalates. Treat disease:Chemotherapy for both forms. A drug for prevention of parasite from development. Pyramid trap: attractive to tsetse flies that are shaped and colored in a way to attact tsetse flies. Mites—scrub typhus transmited by chiggers: 1st instar ―larva‖ stage which has only 6 legs instead of 8. Honorary/Temporary insects. Chiggers bore into skin and deposit saliva. Don’t burrow, just bore. Very tiny and red. Very pretty. Subclass/order of Arachnids: Ticks/Mites 4 prs of walking legs, pedipalps enclose the chelicerates or are fused with them. This is called the hypostome which takes hours to embed in your skin. Diseases are bad but not deadly out here. ―Soft Ticks‖—feed on birds and can eat for 18 months or more without eating. BIG problems are allergies or relapsing fever. 2 years ago in Yosemite there was an outbreak of relapsing fever. Don’t hurt when they bite and feed in 10-15 minutes. ―Hard Ticks‖—VERY different with complex life cycles, 1-5 hosts depending on the tick group. Life cycle can last for years. Diseases: Tularemia, named for Tulare, CA county in 1920’s had an outbreak, and it is sporadic. Caused by bacteria and transmitted by a few species of ticks. Occurs in rabbits and humans can get disease by handling rabbits. Rocky Mountain Spotted Fever (RMSF) in the Bitterroot Valley. 97% of all cases occur east of the Mississippi. Many in the SE U.S. Species of tick is different than the one in the West. Common tick in the east US. Two distinct strains of pathogen: ―T‖ form is mild, ―R‖ strain is virulent and causes more deaths. ―T‖ strain replacing ‖R‖ strain. Ticks transmit viruses. Also cause TICK PARALYSIS when the tick imbeds itself in the back of the skull. This is a slow spreading paralysis of the body. Starts at bottom and works its way up. Treat it by removing the tick! Or wait a while and it will fall off. LYME disease Figures up to 40% of ticks infected with bacteria, but this varies. First found/noticed—Old Lyme, CT. Noticed because lots of cases of juvenile rheumetoid arthritis. Isolated Borrelia burgdorferi in the Ixodes scapulares –related to shape of tick. Rodents: White footed mouse Paramiscus lucipus and this is the reservoir. Larval tick feeds on the mouse. Pathogen in MouseTicksDeer or human or horse. Nymphs also feed on rodents, occasionally on large rodents Adults feed on large mammals including humans and deer. Deer are not affected by parasite. 43 Horses, Dogs and Humans are affected by disease. Cats don’t show symptoms Wasn’t noticed until the 1970’s Treated early with antibiotics okay If you develop the arthritic symptoms, not so easy to exterminate. Why? Pathogen hides in the body and can’t be effected by the antibiotics. Or there is remaining allergic effects. Monday December 1, 2003 BIODIVERSITY Two components: 1. Species Richness: Total number of species in community. An estimate based on a sample. To get ALL species you would have to be working with birds, mammals, maybe butterflies. Others are all estimates. Can be done on higher levels to compare between sites. 2. Abundance: Number of individual per species Species A: 5 , Species B:1, Species: 3 Useful for between sites: Ex. England 3 genera of fly, Brazil 300 genera of fly Why is biodiversity important? Compare richness and abundance between areas and there will be differences. Several explanations: ESA Hypothesis: E: Energy—closer to the equator, there are more species. Toward the poles, overall biodiversity decreases. WHY? ENERGY input from the sun and greater rainfall as you go toward the poles. Called ―Latitudinal Gradient‖ S: Stability of climate—climates do vary over time but will grow back after human interference. Area may change in climate, but overall the change is equaled A: Area—Larger area has more species. It is a logrithmic equation. Birds: 200 ha, 75 species. Caribbean islands reptiles and amphibians: 100,000 sq. km, 120 species. Only truly objective measure is count of species. This may include ―tourists‖ that are just passing through the area. They are not a ―true‖ member of the community. So some are rare and some are common. Unless you know the biology of the species or family level, you will have a hard time deciding what is a member of the community and what is a tourist. Instead you count all and assume tourists won’t make up much of the community. Rothamsted Experiment Station in England—forest and agricultural area. 4,300 species of insects. Still new species appearing. The community could be changing. This is for ―Heavily populated, no original forests known, extremely populated‖ England. To solve the problem, choose a ―focus‖ group. Go out to measure biodiversity by gathering all insects and identifying the foucs group. Maybe pick a family to do comparisions across the world Intermediate Disturbance Hypothesis WHY? Within a site, biodiversity can vary. Mild or infrequent disturbance—not many species. Intermediate, mild disturbances: reset clocks and then have what is there at beginning development and those at end of development cycle and those in the middle. MOST SPECIES in this situation. LOTS of frequent, intense disturbances: not as many species. Developed over time Connell—coral reef works. But in prairie areas that are burned, have low species richness. But there the disturbances are large and have to include areas outside disturbances. There must be a scientific basis for why Biodiversity is ―Good‖ or ―desired‖ In two sites in WMNF: The bowl—2 mile hike in and Spring Brook—also 2 miles in and logged in 1945. Has this disturbance led to changes in abundance or richness. Most common in bowl—1,000 organisms 44 Most commin Spring Brook—500 individuals More individuals, some difference in composition of species, but same number of species This trend is true in many cases of selectively logged and old growth. Not big differences in RICHNESS, just ABUNDANCE. Those species that disappear with removal of large old trees are indicators of old growth forest. Rank abundance can be graphed Log/log normal in undisturbed or slightly disturbed Geometric Series—disturbed areas 100 Geometric log normal Log Series 80 Abundance 60 40 20 0 5 10 15 20 Species Sequence Example of log normalthe meadow at UNH. LOTS of pavement ants Curve will level off when sampling over and over and over Wednesday December 3, 2003—CSI Early Decay-Immediately after death Blow Flies, Flesh Flies-larvae-eat carcase Rove, hister, Burying and another-eat blow flies Another one will only show up when a body has been buried Late Decay-when most of body has been consumed ―Cheese Skippers‖—larvae hop on organism Coffin Flies—later arrive, but came in when coffin was open. ―Ham‖ beetle—Nectrobia Skin beetles—Dermestidae Dry Stage—over the space of years. Trogid beetles During the advanced stages of decomposition, organisms can use flesh,bones, for long periods of time—up to years 45 When do you find bugs that are useful? ---Body is left in back woods off into dirt road area. Conceal body with brush/leaves, or bury 1. After a few days: adult blow flies lay egg—white mass. 100-200 eggs per female. 2. Maggot mass a few days later. 3. Older larvea migrate 4. Larvea move away from corpse and burrow into ground or clothing and pupate 5. Pupal cases remain to show even later stage. Forensic Entomologist study specific insects to predict progression of arrival. Rainfall, temperature, species life history is used to determine time of death General succesion around the world, but you must know characters of species. Calliphora vicina—blow fly is found in many areas of the world. ONLY active in the day and could have first arrived. Active in early spring. So, if that is the only one that was found, it was in the spring or in the fall --Body found in July and so must have pupal cases to say it was there since spring Phormia regina—summer in heavily shaded situations. Lucilia illustris—comes out after Calliphora leaves. Usually only Phormia regina or Lucilia illustris 1. Need to know last time seen alive. 2. These are on exposed bodies: Blow Flies attracted to dead body w/o wounds in 24 hours. Lay eggs in second day. Blow Flies attacted to dead body with wounds in a few hours. There are Mesina on buried bodies: If you find exposed body with blow flies and Mesina, body was buried and then uncovered 3. Need weather info, development of blow flies depends temperature Oldest flies are most useful and are laid first and starting point for forensic determination. Can use pupal cases for identification also 4. More difficult as time goes on Rule of Thumb: 1st month is best for determining time of death. 2 months still possible 3 months not so good. December 5, 2003—Invasive species Creation of pest: 1. Insect you don’t want where it is but only important if costs someone money How it happens: A. Introduction of non-native species to a new area B. Overuse of insecticides that removes parasite or predator. (2 ndary pests) C. Introduce new hosts/crops EXAMPLE: CPB—extreme sw & Mexico and fed on Buffalo burr and extremely nutritious Tomatoes and potatoes came from new world to the old world. Potatoes migrate with people. CPB migrates with potatoes not the 46 99.99% of insects are not pests. From European dirt in ballasts of ships and arrived in Portsmouth, Boston, New York Thoughtgo to country where these come from and see why they aren’t a pest there. Why are they so rare in home area? 1. Need food 2. Survival of babies 3. Natural predators not present in the new location! Population increases until resources are used up. There is ―Natural Control‖—Abiotic and biotic factors that are there. The biotics that are missing: PREDATORS PARASITES PATHOGENS Four PROGRAMS to biological control 1. Natural/Passive control of an endemic species by an endemic species 2. Augmentative control by endeimic speices but never really exert enough pressure without help to control parasites or predators. Bring in many more natives than normally available. Trichogramma are 0.7 mm and do? Lacewings are good too and get them to grow by spraying on ―Wheast‖ to maintain an artificial population until the aphids arrive so eat them. Do to them what kids do to Capri suns—pop in a sucking mouth part, ingest digestive juices, suck out goodies, throw away exoskeleton, get another one. 3. Classical biocontrol: introduced pest species is controlled by populations from the host original country. Then introduce the predatory species to where the pest is now invading. 39% of most important US pests originated from other countries PREDATORS PARASITES PATHOGENS Maybe even competitors Are of interest and fairly specific to the species or genus. If you have an exotic pest, chances are good, ASSUMPTION, there is a specific predator, parasite, or pathogen. MAJOR predator is Coccinallids (lady bird beetles)—on aphids, piercing/sucking homoptera. USDA introduced the ladybird beetles that feed on aphids that weren’t pest before. Harmonia axyridis—doesn’t feed on any aphid of economic importance that were not ever a problem. Introduced 5 times that failed. Introduced the last time and it worked in LA. More Stats: 20% of introductions attempts have succeded. 100 pest species populations are effectively regulated. World wide: 602 documented attempts---16% successful, 58% partial success, 26% failures Not working because: wrong species, wrong climate, 47 120 introduced species to control gypsy moths. 16 species are still here and not controlling. Instead it is the virus that controls gypsy moths. The 16—flies and wasps—are happy to eat big moths like luna moths. ADVANTAGES: 1. Permanent control without extra costs. 2. Cheap in the long run 3. Ex: PEST: Cottony cushion scale: produces wax that flutes out. Parthenogenic and introduced from China/SE Asia to California. Feeds on woody shrubs and trees and wiped out citrus trees. From 20 to 1 trainload per year because of the scale. Koeble—guy who went to find predator of the cottony cushin scale—brought back beetle, Rodolia cardinalis, which only feeds extensively on Cottony cushion scale, and fly, Cryptochetum. It cost $2,000 only at the time. The environmental impact was on the pest. Spotted Alfalfa aphid—wasp was introduced and reduced it as a best Citrus black fly—wasps brought in and reduced the citrus black fly. Others also controlled by classical biological control programs. Plant introduced: Klamath weed: kills cattle, causes eye sensitivity. Two beetles introduced and wiped out plant. Puncture vine: low sprawling plant, produces seeds in a triangluar shape with a point that punctures things. 2 weevils that feed on seeds and no longer is it bad. Tumble weed: so common, that you could make forts of them. Moths introduced and took contol of it. Purple loosestrife: Covers entire swamps, around house it is an ornamental. Plant feeding beetles would eat these. Environmentalists won battle to introduce a bug to control purple loosestrife. DISADVANTAGES: 1. Best on crops where some damage can be tolerated, since there has to be a low level of crop to maintain organisms. 2. Difficult to establish on seasonal crops. Predator and parasite is always lagging behind the pest. Successful in trees: walnuts, olives, plums In the NE, gotta protect the apples! 3. Crossover to non-target species. EX: Gypsy moths parasite that attachs other things. Weevils introduced to control thistle but threatened and endangered species of thistles in NE sandhills are effected. MAIN PEDATORS:neuroptera, wasps, true bugs 48 MAIN PARASITES: flies and wasps MAIN PATHOGENS: bacteria, viruses, nematodes, fungus, protists MAIN bacteria: Bacillus thuringinesis Friday December 12, 2003 Numbers of Species: MOST SUCCESSFUL, INSECTS: 1.5 million described species GUESTIMATE: 5 million as conservative guess. 30 million is other end of scale 400,000 spp. insects in North America 600,000 spp. --Eurasia Crustaceans are second in that ranking lower by an order of magnitude Horseflies300 spp. north of Mexico, 1500 spp. south of Mexico Beetles13 spp. in NH, 180 in Costa Rica So, why are they so successful? p. 47-53 in text 1. 1st animal group to move successfully on to land. As a general rule, TRULY terrestrial—mammals, birds. Compared to bacteria, fungi, protists still not terrestrial. Organisms on land have to adapt to heterogeneous habitats: Changes daily, monthly, seasonally, short and long termspatially and temporally Most successful aquatic organisms: Crustaceans! Marine ―insects‖ Why else? EXTINCTION RATES are low EXAMPLE: Most insects come from modern fauna. Many families we see today were present with the Dinosaurs Triassic, Jurassic, & Cretaceous periods. Many of the genera present in the Tertiary (65-1.8 mya) are present today., even some species look similar! These are old lineages. 2. Hexapod condition—exoskeleton, cuticular waxes, head, thorax, abdomen— successful “design” 3. Development of WINGS:MOST IMPORTANT: why? Locate new food which are scattered, escape from predators, spread to new areas. 99.5% of insects (present day species, estimate) have wings 97% of winged insects can fold them. Odonata, Ephemeroptera can’t. Folders can hide in small places 4. Evolution of holometaboly—complete metamorphasis: egg, larva, pupa, adult 11.5% of insects (present day species, estimate) hemimetabolous 88% of insects (present day species, estimate) holometabolous 0.5% of insects (present day species, estimate) ametabolous LARVA is important in obtaining resourcesEATING MACHINES 49 PUPA is a transitional stage beginning of change in form:wings, legs, genitalia appear. OFTEN where groups diapause ADULTSdispersal & reproduction. If they feed, they feed on something different than larvae. Will feed on something completely different. Some beetles do eat the same thing— particularly the predators. 5. Coevolution of insects and flowering plants Diversity of plants arrived in Cretaceous. Diversity of insects was before that. Looking at insect fossils—static evolution in the Triassic or Jurassic. Then an explosion of diversity in the Cretaceous with the plants. Hymenoptera are parasites on the new plant eating insects. BEES are responsible for plant survival. Insects focus on plant with a specific color or odor and can become consistant visitors of particular plants. This is the success of plants that grow in disperate locations. When wind pollination can’t work, the insects and other winged organisms help out. The insects get the reward of protein: pollen & nectar Gotten to the point of single animal for pollination. As plant species diversified, the insects evolved with them. Currently still diversifying: Coleoptera, Lepidoptera, Diptera are diversified with plants. The Hymenoptera follow these because they are predators on them. 6. Small size, by Daniel Janzen “Why are there so many species of insects?”, 1978 Species packing, as organisms become smaller. Control over environment is low, maximal response to environment due to size Control over environment Habitat heterogenity Bacteria Insect Size of organism Elephant ALLOPATRIC speciation. Dispersal barriers. Move small distances and get to new location Highest insect diversity should be found in areas with high harvestable productivity, the greater number of species that can be supported. Couple this with high spatial heterageneityRain forest, and with moderate disturbance, perterbations. Mid-elevation of tropical rainforests. 50