Rare Invertebrates of the South Okanagan The endangered invertebrates of the south Okanagan are at risk because their ecosystems are at risk. Province of British Columbia Ministry of Environment, Lands and Parks The diversity of that visit our picnics. Velvet ants are invertebrate communities common, too. These are actually wasps in the south Okanagan with wingless females that look like big, W e also don’t know how many in- red, furry ants as they scurry around The diversity of vertebrates can be found in the looking for bee nests to lay their eggs in. invertebrates dry, warm lowlands of the south Spider-hunting wasps are also common T here are many, many different kinds Okanagan and Similkameen val- and diverse – the most striking of these of terrestrial and freshwater inverte- leys, but we can estimate that perhaps is an unnervingly large, black species brates in British Columbia. If we 15 000 species live there. Although with ﬁre-coloured wings, which hunts went through all the reports and many of these are common and wide- the big ‘trapdoor’ spiders of the lists that have been published over the spread, some are conﬁned to the dry grasslands. years, and peered through the museum grasslands of the southern Interior – drawers ﬁlled with specimens, we would and there are literally hundreds that are Alkaline lakes be able to list 20 000 to 25 000 species. found nowhere else in the province. In some of the sagebrush basins lie lakes But when all the surveys are complete These are inhabitants of the Great Basin ringed white with drying carbonate and and all the specimens described and grasslands and wetlands, which extend sulphate salts. These alkaline ﬂats are identiﬁed, the total species count only a few, narrow ﬁngers north into home to another unique community of will probably be about 40 000 to 50 000 Canada. invertebrates. Tiny ground beetles and – about 100 times the number of species brilliantly coloured tiger beetles hunt in of birds! Most of these invertebrates are The shrub steppe and around the mud cracks, and busy arthropods – insects, spiders and their The hot, dry grasslands and shrublands little shore bugs and great ﬂocks of tiny relatives – but molluscs, rotifers, that remain in the south Okanagan and shore ﬂies move along the water’s edge. tardigrades, and various worm phyla Similkameen have an invertebrate Brine shrimp and specially adapted spe- also contribute to the total. fauna quite unlike that of the wetter, cies of dragonﬂies, damselﬂies, beetles, This diversity of species translates forested parts of the province. Sun-lov- and water boatmen bugs paddle and into a diversity of essential ecosystem ing insects abound. Big, black darkling crawl through the clear water. jobs that these invertebrates perform. beetles clamber across the sandy soil; Many insects, including bees, ﬂies, rotund, fuzzy bee ﬂies with patterned Wetlands and riparian woodlands butterﬂies wings hover everywhere; colour- In the valley bottoms, dry grasslands and beetles, Perhaps ful and not-so-colourful butter- give way abruptly to a narrow band of are key play- ﬂies visit spring ﬂowers; grass- moist woodlands along the streams, ers in pollina- species of hopper wings crackle in the hot marshes and lakes. These are home to all tion. As a invertebrates live air; bristly robber ﬂies buzz men- the diverse invertebrates of lush woods critical com- acingly by; and in the warm eve- – shade-loving ﬂies, moths, wood-bor- ponent of the in the South nings, scorpions scramble out ing beetles, and many others. In the food chain, Okanagan from under ﬂat rocks and the warm, rich wetlands themselves are spe- invertebrates songs of crickets ﬁll the dark void. cial communities of dragonﬂies, diving provide food lowlands. The group of insects that prob- beetles, backswimmers, snails, mussels for other ani- ably symbolizes the hot shrub and clams. mals. Earthworms and other soil- steppe the most, however, are the Hy- inhabiting creatures help to create menoptera – the bees, ants and wasps. Why are invertebrates productive soil. Many plants are An astounding number of wasps hunt at risk? D dependent on fungal associations across the sunny meadows, especially espite our general ignorance of in- with their roots and invertebrates where sandy soil makes digging nesting vertebrates, we can say that the en- are important as dispersers of fungal burrows easy. Many species of several dangered invertebrates of the south spores. The many predacious and families of ‘sand wasps’ live here – some Okanagan and Similkameen valleys parasitic invertebrates are vital in red and black with long and slender are threatened not by direct exploita- the control of unwanted plants and bodies and thread-like waists; some tion, but by loss or degradation of their other invertebrates that humans banded with yellow and black, resem- habitats. They are at risk because their consider pests. bling the (unrelated) yellowjacket wasps ecosystems are at risk. The rich soils of the grasslands wetlands and dry uplands between are a valuable agricultural resource, Oliver and Osoyoos Lake. Only two tiny and have been ecological reserves exist in the ploughed and ir- Many species south Okanagan, one of which rigated to pro- has burned completely, illustrat- duce tree fruits, are restricted ing the need for a larger, more grapes, and veg- to ecosystems comprehensive conservation Western Ridge Mussel etables. Pesticide program in the valley. Gonidea angulata (Lea) use has probably that are Various government agencies This freshwater mussel (Order had a great im- themselves and public organizations Unionoida) is known in Canada only pact on native in- have tackled this problem by from the main, valley bottom water sects living in endangered. forming the South Okanagan bodies from Penticton south. There and around agri- Conservation Strategy (SOCS). have been few searches for it, and the cultural areas. Heavy grazing has altered SOCS coordinates activities in research, only recent records are from the the plant composition of grasslands and land acquisition and habitat manage- Okanagan River at Okanagan Falls, has undoubtedly changed their inverte- ment. Vaseux Lake and Osoyoos Lake. The brate communities as well. Recreation unionid mussels – the family that the use, especially off-road vehicle trafﬁc, Rare invertebrates in western ridge mussel belongs to – are has also damaged grasslands. In the val- the south Okanagan very sensitive to environmental changes ley bottoms, streamside woodlands and lower Similkameen and consequently have a high percent- A have been cleared and converted to hay s of 1994, 23 invertebrates are age of endangered species within their meadows. known only from this small region ranks throughout North America. Humans continue to ﬂock to this re- in the world and an additional 75 gion to enjoy its ﬁne climate and, as cit- occur nowhere else in Canada. As ies expand, wetlands are drained and mentioned earlier, of course, our ﬁlled, and the dry benchlands paved and knowledge of invertebrate ranges and developed into suburban subdivisions. status is poor, and new, intensive sur- In the early 1950s, the Okanagan River veys are needed to further clarify the sta- was channelized and dyked, altering tus of many of these animals. A provin- forever the water ﬂow and natural cial report has ﬂooding regime that created the Twenty-three named this area Parowana Tiger Beetle marshes and lush riparian wood- Cicindela parowana Wick. lands along its course. invertebrates one of the two highest priority The Parowana Tiger Beetle (Order Today, only about 10 percent are known areas for such Coleoptera) dwells on alkaline ﬂats of the south Okanagan grasslands remain in a relatively natural state, only from this surveys. our Despite where, as its name suggests, it ambushes and consumes other invertebrates. In and only about 15 percent of the small region scanty knowl- Canada it is known only from Ok- valley’s wetlands still exist. Pro- tected areas and other areas man- in the world. edge, up listscan draw we of anagan Falls, Oliver, and Penticton. It hasn’t been seen recently in any of these aged for wildlife are few and cover invertebrates that areas, and the Penticton site has been less than 3 percent of the southern val- are almost assuredly threatened or en- destroyed by housing developments. leys. Most are concentrated around dangered in these valleys. These are spe- Vaseux Lake, where BC Environment, cies that are relatively large and obvious Vivid Dancer Argia vivida Hagen BC Parks, the Nature Trust of British but still rarely seen or collected, and that In southern British Columbia, this Columbia, and the Canadian Wildlife are restricted to ecosystems that are lovely damselﬂy (Order Odonata) lives Service all hold lands for the conserva- themselves endangered. From this sort around spring-fed pools and streams in tion of wetland, grassland, rocky bluff of list, we have chosen ten representa- a very few, scattered localities, mostly and dry forest ecosystems. The recently tives from different invertebrate groups associated with hot springs. Most of created South Okanagan Wildlife Man- and from a range of endangered habi- these habitats are vulnerable to develop- agement Area protects riverside tats. Their stories follow. ment, and the damselﬂy populations are pions and shun the sunlight, preferring later. Don’t confuse this mantid with to hunt at night. They live in sandy, dry the much larger Praying Mantid, which areas, hiding under stones or in shallow was brought to the Okanagan from burrows during the day. They are arach- Ontario to control grasshoppers. This nids, relatives of spiders and scorpions, species, originally introduced to eastern but are easily recognized by their large North America from Europe, comes in heads and massive jaws (chelicerae), brown and green forms and is fully threatened. In the South Okanagan only which they use to capture and crush winged in both sexes. two sites are known; both are small their invertebrate prey. We know hardly rangeland streams originating in cold anything about the six species that are springs, and both are disturbed by cattle known from the south Okanagan – in or horses. The aquatic larvae cling to the fact, three of these species have been dis- undersides of stones and roots in the covered only recently and have not yet small, trickling streams and muddy received ofﬁcial, scientiﬁc names! pools. The adults rest on stones or bare earth nearby, or make low foraging ﬂights after small insect prey. Females Apiocerid Fly lay eggs in aquatic vegetation, often sub- Apiocera barri Cazier merging themselves in the process. This ﬂy is the only member of the Fam- Meanwhile, the males protect their ily Apioceridae (Order Diptera) occur- mates from the attentions of other ring in Canada, where it is restricted to males by retaining their mating hold on the southern Okanagan Valley. In ﬁeld the female’s thorax and standing stifﬂy guides, members of this family are usu- at attention. ally called “ﬂower-loving ﬂies,” but re- Ground Mantid search shows that Apiocera species, at Litaneutria minor (Scudder) least, hardly ever live up to this name. Mantids (Order Mantodea) are car- They inhabit sandy, arid and semiarid nivorous insects distantly related to habitats, and most ﬂies observed never grasshoppers. They are easily recog- visit ﬂowers, but rather are found run- nized by their long, slender, neck-like ning on the ground, especially near the thorax and grasping front legs. The sparse vegetation, where they may feed Ground Mantid is the only mantid na- on honeydew beneath aphid-infested Sun Scorpion tive to Canada. In this country it is plants. They are often seen drinking Eremobates gladiolus Muma known only from the dry grasslands of from damp sand with their sponge-like Sun scorpions (Order Solpugida), de- the extreme South Okanagan near mouth-parts. The carnivorous larvae spite their common name, are not scor- Oliver and Osoyoos. This enigmatic, live in loose soil and evidently feed on rare predator lives mostly on the other invertebrates there. Look for these The south Okanagan occupies a tiny ground and low in shrubs such as ﬂies on hot days in August. fraction of the area of the province sage and antelope brush, where its dusty brown colour makes it hard to ﬁnd. The males are usu- ally fully winged, but females are ﬂightless – their wings are greatly Robber Fly reduced, less than one-third the Megaphorus willistoni (Cole) length of the abdomen. In the late summer and fall, females lay a Only one specimen of small, rectangular egg mass about this small robber ﬂy (Order Kamloops 7 mm long on the stems of low Diptera) has been recorded in Canada, shrubs. The eggs overwinter and just a few hundred metres from the In- hatch about six or seven months ternational Boundary in the southern Similkameen Valley. females seek out the bur- These are squat little ﬂies rowing larvae of big bristling with grey and yel- scarab beetles. They para- low hairs, which give them lyse each grub and lay an an uncanny resemblance egg directly on it – and to leaf-cutter bees as they the wasp larva consumes buzz from plant to plant, the beetle grub where it hovering here and there in lies. The scarab beetles search of prey. They live in themselves are probably grasslands and seem to rare and have a restricted prefer areas with many distribution. Thus far, ﬂowers, since this is where these wasps are known their favourite prey, small only from Chopaka in bees and wasps, abound. the lower Similkameen Like all robber ﬂies, they . Robert Cannings photo Valley and the sandy capture their prey in their benchlands east and bristly legs and kill it with north of Osoyoos Lake, toxic saliva injected through their short where much of their habitat was proboscis. The dissolved tissues are then destroyed by ﬁre in 1993. sucked back up through the proboscis. Eggs are laid in a case-like mass on a What can we do? O dead plant stem; the larvae develop in ne of the ﬁrst priorities is to ﬁnd out the soil where they apparently prey on more about our rare invertebrates – other insect larvae. where exactly are they, and what sort Viceroy of habitats do they need? It is critic- Limenitis archippus (Cramer) al to bring together information The orange and black Viceroy (Order from specimens that have already Lepidoptera) is the famous mimic been collected and of the poisonous Monarch butter- One of the housed in muse- ﬂy. Although the Monarch still persists in small numbers in the ﬁrst priorities ums across North America. This ba- Thompson and Okanagan valleys, is to ﬁnd out sic information is the Viceroy has disappeared completely from the province, more about vital toof inverte- edge our knowl- Mormon Metalmark probably a victim of orchard pesti- our rare brate species’ dis- Apodemia mormo (Felder and Felder) cides. It would have been especially This handsome butterﬂy (Order Lepi- susceptible to these chemicals invertebrates. tribution and eco- logical needs. The doptera) of western North America was since some of its favourite larval Royal British formerly found at several sites in the re- food plants are domestic fruit trees. Columbia Museum and the Spencer gion, but is now known only from one Entomological Museum at the Univer- population near Keremeos. Elsewhere Scoliid Wasp sity of British Columbia have important in Canada another subspecies is found Campsomeris pilipes collections of Okanagan insects. In con- in extreme southern Saskatchewan. The (Saussure) junction with museums, the Conserva- adults, which ﬂy in August, sip nectar These huge, grey and tion Data Centre in the Wildlife from wild buckwheats. The nocturnal yellow wasps (Order Branch can keep track of this infor- larvae eat the leaves and stems of the Hymenoptera) can mation in the same way it now same plants, living in a silken nest be seen hov- manages data on rare vertebrates during the day. ering low and plants. At the same time, detailed, over sandy but focused inventories of species soil, where the and their habitats are urgently ’ . , . Steve Cannings photo David Shackleton photo needed to increase our knowledge. But even before all the information is on public land. We can get involved in Education is vital, too. Invertebrate in, we must act quickly to protect the public processes to develop land use conservation will not be supported if no natural communities that still remain in plans and regulations that preserve, one has heard of the animals in ques- these special valleys. rather than destroy, natural diversity. tion. Invertebrates, despite their vast di- What can we do as individuals? We And we can maintain natural habitat versity and ecological importance, have can get involved with local naturalist or- on our own property and encourage not had the attention, either from re- ganizations to learn more about the governments to develop incentives for searchers or managers, that other or- natural world in our neighbourhood. others to do the same. ganisms such as mammals, ﬁsh, birds We can encourage all levels of govern- and trees have had. ment to protect natural communities , : Wildlife Branch BC Environment Ministry of Environment, Lands and Parks 780 Blanshard Street Victoria, British Columbia V8V 1X4 BRITISH COLUMBIA CONSERVATION DATA CENTRE B.C. Conservation Data Centre --- . , Printed in British Columbia on recycled paper with vegetable base inks. ..
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