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, 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 here are many, many different kinds WOkanagan 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 Twent 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- species of flies visit spring flowers; grass- moist woodlands along the streams, ers in pollina- 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- in the South acingly by; and in the warm eve- – shade-loving flies, moths, wood-bor- ponent of the 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 lowlands. songs of crickets fill the dark void. cial communities of dragonflies, diving provide food 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? 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 D 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- are restricted has burned completely, illustrat- duce tree fruits, ing the need for a larger, more grapes, and veg- to ecosystems comprehensive conservation Western Ridge Mussel etables. Pesticide that are program in the valley. Gonidea angulata (Lea) use has probably 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- endangered. have tackled this problem by from the main, valley bottom water sects living in 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- 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- A 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- invertebrates one of the two Cicindela parowana Wick. lands along its course. 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 only from this surveys. where, as its name suggests, it ambushes remain in a relatively natural state, Despite our 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- in the world. edge, we can anagan Falls, Oliver, and Penticton. It tected areas and other areas man- draw up lists of 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 length of the abdomen. In the late willistoni (Cole) summer and fall, females lay a Only one specimen of this small robber fly (Order Kamloops small, rectangular egg mass about 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? 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 O 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 first priorities ums across North persists in small numbers in the America. This ba- Thompson and Okanagan valleys, is to find out sic information is the Viceroy has disappeared more about vital to our knowl- completely from the province, edge of inverte- Mormon Metalmark probably a victim of orchard pesti- our rare brate species’ dis- Apodemia mormo (Felder and Felder) cides. It would have been especially invertebrates. tribution and eco- This handsome butterfly (Order Lepi- susceptible to these chemicals 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
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