Saskatchewan Aquatic Macroinvertebrates

Aquatic macroinvertebrates form an integral part of aquatic ecosystems in Saskatchewan. Not only are they diverse, with over 1500 species (Parker and Lehmkuhl, 1999) found in the province, they are extremely important in recycling plant and animal material back into the food web. They are also important food for fish and waterfowl. Adult insects, when they emerge from the water, are important food for popular insectivorous birds. And, most of the familiar biting insects (mosquitoes, blackflies, horseflies, deer flies and no-see-ums) start their life cycles in lakes, ponds, rivers and streams of the province . Because they are such an important part of aquatic ecosystems macroinvertebrates are often used to determine the impact of developments (mines, forestry) and to assess the effects of contaminants (pesticides, sewer effluent, etc.) on the aquatic environment. They are used in this role because they are diverse, each species reacts to disturbances and pollutants in a characteristic manner, they respond quickly due to their short life cycle and they are relatively sedentary so they can not leave the contaminated area as do more mobile fish species.

Insects form the bulk of the aquatic macroinvertebrate fauna of the province with over 1200 species (Parker and Lehmkuhl, 1999). Twelve major groups, or orders, of insects have members that live a part of their lives in or on the water. They include: Collembola (Springtails), Ephemeroptera (Mayflies), Odonata (Dragonflies and Damselflies), Plecoptera (Stoneflies), Hemiptera (True bugs), Coleoptera (Beetles), Trichoptera (Caddisflies), Lepidoptera (Moths), Megaloptera (Dobson flies), Neuroptera (Spongilla flies), Diptera (True flies), and Hymenoptera (Wasps). In addition to the insects there are Annelida (Aquatic worms and Leeches), Mollusca, and Crustacea that are found in the waters of Saskatchewan.

The flora and fauna of Canada and most of Saskatchewan were eliminated by the advancing ice sheets of the Wisconsin glaciation (100,000 to 17,000 BP)(Pielou 1991). In what is now Canada only areas in the northwestern arctic (Beringia), and small areas on the extreme west coast, the mouth of the St. Lawrence and Maritimes and the Cypress Hills and along the Montana-Saskatchewan border were free from ice. To the south of the ice sheet three general regions acted as refugia; the temperate southeast from the east coast of North America to the Appalachians and Mississippi River; the central region between the Mississippi and the western mountains; and the Pacific mountain refugium. The aquatic macroinvertebrate fauna present in Saskatchewan today is the result of immigration (red arrows on map) from these refugia into the province after glaciation (Lehmkuhl 1980). Periods of glacial advance and retreat severed and re-established links between Saskatchewan and the three southern refugia and Beringia as well as the eastern Canadian refugia (Christiansen 1979, Flannagan and Flannagan 1982, Pielou 1991). As the ice sheets retreated the flora and fauna began recolonizing the newly exposed regions. Due to its geographical location in the continent Saskatchewan has an aquatic insect fauna that originated from all of the major refugia but the majority have colonized from the three refugia to the south (Lehmkuhl 1980).

Our knowledge of aquatic insects and aquatic macroinvertebrates found in Saskatchewan is, for the most part, very dated with many gaps in our information base. A number of insect groups (Ephemeroptera, Hemiptera, Plecoptera, Culicidae, Simuliidae, Odonata) were comprehensively examined in the province between 1965 and 2002, but many of these treatments are need of major revisions with regard to taxonomic names, species lists, species distributions and ecologies. A thorough and ongoing examination is required to update the changes in taxonomies and improve our knowledge. Collecting in new areas of the province and revisiting frequently collected sites will undoubtly add to the species lists of many groups and provide information on temporal community changes that may be related to water quality changes caused developments and/or climate change: for example; Hoemsen etal (2014), Phillips etal (2013), Phillips et al (2008), Parker and Phillips (2007), Webb etal (2007) and Webb etal (2004). Unfortunately, in the present climate of funding for basic biodiversity research that pervades governments, academia and industry this lack of knowledge will persist for many years and decades to come.

References and further reading:

Christiansen E.A. 1979. The Wisconsin deglaciation of southern Saskatchewan and adjacent areas. Can.J.Earth Sci. 16:913-938.

Dosdall, L. M. and D. J. Giberson. 2014. Stoneflies (Plecoptera) of the Canadian Prairie Provinces. In Arthropods of Canadian Grasslands (Volume 3): Biodiversity and Systematics Part 1. Edited by H. A.Cárcamo and D. J. Giberson. Biological Survey of Canada. pp. 201-229. © 2014 Biological Survey of Canada. ISBN 978-0-9689321-6-2 doi: Species checklist available at

Flannagan, P.M. and J.F. Flannagan. 1982. Present distribution and post-glacial origin of the Ephemeroptera, Plecoptera and Trichoptera of Manitoba. Manitoba Dept. of Nat. Res. Fish. Tech. Rep. No. 82-1.

Hoemsen, BM, ID Phillips, DW Parker, AJ Bell, JA Bergsveinson, JS Armstrong and DP Chivers. 2014. Extended family: a caddisfly new to Saskatchewan, Canada with notes on the life history of Neophylax splendens (Trichoptera: Thremmatidae). Can. Ent.

Lehmkuhl, D.M. 1980. Temporal and spatial changes in the Canadian insect fauna: Patterns and explanations. Can. Ent. 112:1145-1159.

Miyazaki, R. and D. M. Lehmkuhl. 2011. Insects of the Saskatchewan River System in Saskatchewan. In Arthropods of Canadian Grasslands (Volume 2): Inhabitants of a Changing Landscape. Edited by K. D. Floate. Biological Survey of Canada. pp. 119-157.

Parker, D. and I. Phillips. 2007. Collection records of three aquatic bugs (Heteroptera); pygmy backswimmer (Pleidae), water scorpion (Nepidae) and marsh treader (Hydrometridae) for Saskatchewan, Canada. Blue Jay. 65:143-148.

Parker, D.W. and D.M. Lehmkuhl, 1999. Diversity of aquatic macroinvertebrates in Saskatchewan. In. Thorpe, J., T.A. Steeves, and M. Gollop. Proceedings of the 5th Prairie Conservation and Endangered Species Conference. Saskatoon, SK. Feb. 19-22, 1998. Natural History Occasional Paper No.24.Provincial Museum of Alberta, Edmonton, Alberta. Pp. 306-311.

Pielou, E.C. 1991. After the Ice Age: The Return of Life to Glaciated North America.University of Chicago Press, Chicago.

Phillips, ID, D Parker, BM Hoemsen, AJ Bell, and DP Chivers. 2013. Biological notes and range expansion of the non-biting midge Odontomesa fulva (Kieffer) (Diptera: Chironomidae). Western North American Naturalist 73: 244–247

Phillips, I.D., D. Parker, and G. McMaster. 2008. The aquatic invertebrate fauna of a northern prairie river: range extensions and water quality characteristics. Western North American Naturalist 68:173-85.

Webb JM, Sun LL, McCafferty WP, Ferris VR. 2007. A new species and new synonym in Heptagenia Walsh (Ephemeroptera: Heptageniidae: Heptageniinae) based on molecular and morphological evidence. 16pp. Journal of Insect Science 7:63, available online:

Webb, J., D.W. Parker, D.M.Lehmkuhl, and W.P. McCafferty. 2004. Additions and emendations to the mayfly (Ephemeroptera) fauna of Saskatchewan, Canada. Ent. News 115:213-218

Wrubleski, D. A. and L. C. M. Ross. 2011. Aquatic Invertebrates of Prairie Wetlands: Community Composition, Ecological Roles, and Impacts of Agriculture. In Arthropods of Canadian Grasslands (Volume 2): Inhabitants of a Changing Landscape. Edited by K. D. Floate. Biological Survey of Canada. pp. 91-116.