Insect Pollinators

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					                                                        Introduction to
                                    Insect Pollinators
     O regon’s primary pollinators are native bumble bees, sweat bees, mining bees, wasps,
  butterflies, and moths. Imported European honey bees also play a critical role in pollinating
            crops. This guide will help you recognize the characteristics of pollinators
                           and their requirements for food and shelter.

                                         Bumble bees are social insects that     All species nest in the ground. Hal-
   Native Pollinators                    build their nests in the ground, of-    ictids have a range of nesting hab-
Native bees are easily overlooked        ten in abandoned mouse burrows,         its, from dispersed solitary nests, to
since most do not fit the stereo-         empty bird nests, and under fall-       densely situated ones with individ-
type image, like the European            en grass. The mated queen over-         ual bees sharing common entrance
honey bee, with black and brown-         winters in the soil while the rest of   ways, to primitive social arrange-
ish stripes, living with thousands       the colony dies at the onset of cold    ments. Halictid bees are common
of others in a hive full of honey-       weather. In early spring, she estab-    insects and good general pollina-
comb. About 4,000 species of na-         lishes a new nest and rears the first    tors.
tive bees have been identified and        worker brood. These workers are
catalogued in North America. They        small, sterile females that enlarge
range in length from less than one       the nest, forage, and tend to the                                 Mining
eighth of an inch to more than one       next generation of workers. These                                 Bees
inch; vary in color from dark brown      are larger bees, due to changed                                  Andrenid
or black to metallic green and blue;     nest conditions, such as increased                               b e e s ,
and may have stripes of red, white,      temperature, cell size, and food                                 common-
orange, or yellow.                       availability. Produced in late sum-                              ly   called
                                         mer are the fertile females (next                                mining
                                         year’s queens) and males (called                                 or digger
                        Bumble Bees      drones), whose sole function is to                               bees, are
                      There are 49       fertilize the queens before dying in                             another
                      species    of      the fall.                                                        common
                      bumble bees                                                                         pollina-
                      in the Unit-                                                                        tor. They
                      ed    States.                             Sweat Bees       resemble the typical honey bee in
                      About 19 of                                Sweat     bee   shape and size. Their bodies are
these are found in Oregon.                                       is the com-     dark in color and covered with fine,
                                                                 mon name        light brown or yellow hairs.
Bumble bees are excellent pollina-                               for bees in
tors, especially of berry species.                               the Halicti-    Andrenid bees have chewing-lap-
While bumble bees are general-                                   dae family,     ping mouthparts used to manipu-
ist foragers that visit a diversity of                           and they are    late and collect nectar and pollen.
flowers, a few groups of flowers,                                  named for       The protruding, ‘lapping’ mouth-
such as willows and lupines, are         their attraction to the salts in hu-    part is shorter in mining bees than
particularly important to them.          man perspiration. Most sweat bees       honeybees, giving them the com-
                                         are small to medium in size, 1/8 to     mon name of short-tongued bees.
Bumble bees practice what is called      3/8 of an inch long. They are gen-      As their name suggests, mining
‘buzz pollination’ where they grab       erally black or metallic, and some      bees dig single nests in the soil.
onto the anthers, the pollen-bear-       are brilliant green or brassy yellow.   Mining bees are solitary and do
ing structure, of certain flowers and                                             not form large, socially organized
buzz their flight muscles to release      Sweat bees are among the most           nests. However, thousands of indi-
the pollen. This behavior is espe-       common bees. There are about            viduals may nest in a general area
cially important in pollinating blue-    1,000 species in the United States,     with good nesting habitat.
berries, cranberries, and tomatoes.      Canada, and Central America.
                      Wasps             gressive than other types of wasps.
                       Like    bees,    Their nests are always enclosed                 Other Pollinators
                       yellowjack-      with a papery envelope and can be
                       ets and hor-     found in the ground, hanging from                                 Syrphid Flies
                       nets belong      eaves or tree branches, and occa-                                 Syrphid flies,
                       to the insect    sionally in wall voids.                                           also    known
                       order    Hy-                                                                       as hover flies
                       menoptera.       The Bald or White Faced ‘Hornet,’                                 for their abil-
These species are beneficial to hu-      is scientifically not considered to                                ity to hover
mans for pest control and some          be a hornet, but a large wasp. Its                                in flight, are
pollination. In addition, thousands     coloration is black and white. Their        common predators of aphids and
of small wasp species are parasites     nests are found in trees or shrubs          other soft bodied insects. Because
of other insect pests, particularly     and they become very large by               Syrphid flies feed on pollen, nectar,
aphids and caterpillars. Without        summer’s end. The size of the nest,         and aphid honeydew, they can also
parasitic wasps, pests would over-      number of individuals in a colony,          act as pollinators. They mimic the
take most crops.                        and the active time beyond summer           appearance of bees or wasps as a
                                        all depend on the species.                  protective strategy. There are mul-
                       Yellowjackets                                                tiple species of Syrphid flies in Or-
                       can be both                                                  egon.
                       beneficial and
                       wasps. They      Non-native Pollinators                                               Butterflies
                       are important                                                                        Butterflies,
                       predators and                               European                                 as well as
                       scavengers,                                 Honey Bees                               m o t h s ,
helping to control pests and recycle                           European                                     can serve
organic materials, but can also be a                           h o n e y                                    as    pol-
threat to humans due to their abil-                            bees play                                    linators.
ity to sting repeatedly in defense of                          a     critical                               There are
their nests. Yellowjackets are rela-                           role        in       approximately 170 species of but-
tively short and stout, holding their                          pollinating          terflies in Oregon that are found
legs close to their body compared       crops. They are the pollinator we           at sea level, on mountaintops, and
with other wasps. Paper wasps,          know how to best manage and move            everywhere in between. Some range
for example, are more slender and       for agriculture. However, in recent         throughout North America or even
have long, dangling legs. All yel-      years they have been plagued by             other continents. Others, like the
lowjackets are striped either black     pests, diseases, and most recently,         Oregon swallowtail, are unique to
and white or black and yellow. They     the mysterious colony collapse              the Pacific Northwest.
are rapid fliers, and are more ag-       disorder.

Improve pollinator habitat on your property...

The USDA Natural Resources              Look for opportunities to improve           The Xerces Society is a non-
Conservation Service (NRCS)             pollinator habitat with these NRCS          profit organization that works
provides voluntary technical and        conservation programs:                      with farmers and scientists to
financial assistance to help private                                                 protect habitat that supports
landowners plan, design and install      Conservation Security Program              pollinators. The Xerces Society
conservation treatments. Ask             Conservation Technical Assistance          provides plant lists, crop-specific
your local NRCS about practices          Environmental Quality Incentives Program   fact sheets and other guidance for
to benefit pollinators. Locate your       Wetlands Reserve Program                   protecting pollinator habitat. More
service center online at:                                                           information can be found at:
                                         Wildlife Habitat Incentives Program                                                         

                              USDA is an equal opportunity provider and employer.
                                                       June 2007

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