Caddisflies of the Yukon - Department of Biological Sciences ...

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790 G.B. Wiggins and C.R. Parker Table of Contents (continued) Suborder Annulipalpia Family Hydropsychidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796 Family Philopotamidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 797 Family Polycentropodidae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 798 Suborder Integripalpia Family Apataniidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799 Family Brachycentridae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 799 Family Goeridae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 Family Lepidostomatidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 Family Leptoceridae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 801 Family Limnephilidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 803 Family Molannidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809 Family Phryganeidae. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 809 Family Uenoidae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 811 Taxonomic notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 811 Biogeographic analysis of the Yukon and Beringian Trichoptera . . . . . . . . . . . . . . . . . . . . . . . . . 820 Geological and climatic context . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 820 Biological aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 821 Origin of the Beringian and Holarctic Trichoptera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 824 I. Nearctic species widespread in North America . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 825 Greenland Trichoptera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 828 II. Holarctic species widespread in North America . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 830 III. Palaearctic-East Beringian species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 839 IV. Beringian species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 849 V. Holarctic species not in Beringia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 852 Ecological considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 854 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 861 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 862 Introduction In this study we have undertaken to examine the Trichoptera of the Yukon Territory of northern Canada from a dynamic viewpoint. Several lines of biological investigation coincide to make the Yukon especially appropriate for such an analysis. Repopulation of the Yukon following the last recession of Pleistocene glaciers is of unusual biogeographic interest because the western half of this area was part of the unglaciated Beringian refugium that extended westward through central Alaska, over the exposed continental shelf underlying Bering Strait and adjacent coastal areas, and incorporating a large part of northeastern Asia. While northern North America and extensive areas of Europe and Asia were covered by ice during the last glacial (Wisconsinan) advance, the unglaciated Beringian refugium harboured cold-adapted species, enabling some of them to move from one continent to the other across the Bering land bridge connecting North America and Asia. Evidence indicates that a number of the species in the present trichopteran fauna of the Yukon entered North America in this way and passed the Pleistocene glacial periods in the Beringian refugium, while most Nearctic species were confined to the south of the advancing front of the Laurentide continental and Cordilleran montane glaciers. From an ecological viewpoint, an investigation of Yukon Trichoptera offers an opportunity to contrast the ecological success of a diverse group of aquatic insects at high latitudes with the success of the same group in more temperate parts of North America. The species advancing from southern refugia as the glacial ice receded had to contend with different habitat conditions at higher latitudes. For terrestrial insects, evidence on the ecological costs
Caddisflies of the Yukon 791 imposed by these conditions is available from a number of groups; but for aquatic insects other than Chironomidae (e.g. Oliver 1968) there is little evidence or synthesis. To what extent did longer colder winters, shorter summers, and shorter photoperiods influence the success of a group of insects with wholly aquatic larvae? Trichoptera are especially appropriate for seeking answers to questions of this kind because of their relatively high diversification; apart from Chironomidae, there are more species of Trichoptera than of any other group of freshwater insects, and those species occupy an exceptionally wide range of aquatic habitats and ecological niches (Wiggins and Mackay 1978). Combining both biogeographic and ecological viewpoints, investigation of the Yukon Trichoptera reveals results in nature when related species of Nearctic and Palaearctic origins come together to form aquatic communities. As an ecological testing ground for these natural experiments, the Yukon is well suited because of its high diversity of aquatic habitats. Mountain ranges divide the land into several major drainage systems, giving rise to small rapid streams, which in turn unite to form river systems of increasing order and potential biological diversity. Marshes, ponds, and lakes abound, providing rich resources for aquatic insects adapted for life in lentic waters. The treeline, southern margin of the arctic biome, passes through the northern Yukon at about latitude 67°N. To the north, arctic tundra extends to the Arctic Ocean; on the slopes of the mountains, biotic zones range through coniferous forests to alpine tundra and ice-fields. Although freshwater habitats are highly diverse within the Yukon, the success of insects in forming aquatic communities under climatic conditions of high latitudes is not well understood. Therefore, examination of these fundamental biological issues can add to our understanding of the biology of Trichoptera; the same issues underlie management of aquatic systems in the Yukon Territory. The analysis begins, necessarily, with a survey of the species of Trichoptera known to occur in the Yukon. Systematic interpretation of the species has been aided by the advanced state of knowledge on the Trichoptera of Russia (e.g. Lepneva 1964, 1966; Martynov 1924a), and by the recent synthesis of aquatic insects of the Russian Far East by I.M. Levanidova (1982). Materials and Methods Most of the collections of Trichoptera studied were made by field parties from the Department of Entomology, Royal Ontario Museum (ROME), over a 4-year period from 1979 to 1982, and are deposited there. Collections from other institutions were also studied: Canadian National Collection of Insects, Ottawa (CNCI); Illinois Natural History Survey, Champaign, Illinois (INHS); Royal British Columbia Museum (BCPM); U.S. National Museum of Natural History (USNM); University of British Columbia Insect Collection, Vancouver (SMDV); Zoological Institute, Russian Academy of Sciences, St. Petersburg (ZMAS). All species known from the Yukon Territory are listed, including species recorded in the scientific literature but not represented in the material we examined—principally records compiled by Nimmo and Wickstrom 1984 (henceforth NW 1984). Although we have many larval collections, these records are included only if larvae are the single source of evidence, as for Allomyia, or can be identified reliably to species as in some Hydropsyche. Distributional records are grouped by ecogeographic regions of the Yukon (Fig. 1); the detailed list of our records is too long for inclusion here, but is deposited in the library of the Royal Ontario Museum. At this early stage in understanding the distribution of Trichoptera in the Yukon, the records are highly correlated with the access roads; however, some general patterns seem to emerge. Biological and distributional characteristics of the higher taxa are
Page 1 and 2: Caddisflies of the Yukon FRONTISPIE
Page 3: Caddisflies of the Yukon 789 and ta
Page 7 and 8: Caddisflies of the Yukon 793 outlin
Page 9 and 10: Caddisflies of the Yukon 795 Genus
Page 11 and 12: Caddisflies of the Yukon 797 25. Ch
Page 13 and 14: Caddisflies of the Yukon 799 are de
Page 15 and 16: Caddisflies of the Yukon 801 53. Le
Page 17 and 18: Caddisflies of the Yukon 803 Family
Page 19 and 20: Caddisflies of the Yukon 805 85. Gr
Page 21 and 22: Caddisflies of the Yukon 807 Biolog
Page 23 and 24: Caddisflies of the Yukon 809 Biolog
Page 25 and 26: Caddisflies of the Yukon 811 Genus
Page 27 and 28: Caddisflies of the Yukon 813 FIGS.
Page 35 and 36: Caddisflies of the Yukon 821 above
Page 37 and 38: Caddisflies of the Yukon 823 was mu
Page 39 and 40: Caddisflies of the Yukon 825 recogn
Page 41 and 42: Limnephilus extractus Walker (99) L
Page 43 and 44: Apataniidae Apatania zonella (Zette
Page 45 and 46: Integripalpia Apataniidae Apatania
Page 47 and 48: Caddisflies of the Yukon 833 wester
Page 49 and 50: Caddisflies of the Yukon 835 Micras
Page 51 and 52: Caddisflies of the Yukon 837 been b
Page 53 and 54: Caddisflies of the Yukon 839 years,
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other reasons, most Palaearctic-Eas
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Caddisflies of the Yukon 843 In add
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Caddisflies of the Yukon 845 FIG. 2
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Caddisflies of the Yukon 847 FIGS.
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Caddisflies of the Yukon 849 press)
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Caddisflies of the Yukon 851 Pleist
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Caddisflies of the Yukon 853 Hydrop
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Caddisflies of the Yukon 855 TABLE
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Caddisflies of the Yukon 857 genera
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Caddisflies of the Yukon 859 strong
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Caddisflies of the Yukon 861 assure
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Caddisflies of the Yukon 863 Gislas
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Caddisflies of the Yukon 865 Reeves
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