THE MAYFLIES OF SASKATCHEWAN A Thesis Submitted to the College of Graduate Studies and Research in Partial Fulfillment ofthe Requirements for the Degree ofMaster ofScience in the Department ofBiology University of Saskatchewan Saskatoon By Jeffrey Michael Webb December 2002 © Copyright Jeffrey Michael Webb, 2002. All rights reserved. PERMISSION TO USE In presenting this thesis in partial fulfilment ofthe requirements for a Postgraduate degree from the University ofSaskatchewan, I agree that the Libraries of the University may make it freely available for inspection. I further agree that permission for copying ofthis thesis in any manner, in whole or in part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their absence, by the Head ofthe Department or the Dean ofthe College in which my thesis work was done. It is understood that any copying, publication, or use ofthis thesis or parts thereoffor financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University ofSaskatchewan in any scholarly use which may be made ofany material in my thesis. Requests for permission to copy or to make other use ofmaterial in this thesis in whole or part should be addressed to: Head ofthe Department ofBiology University ofSaskatchewan Saskatoon, Saskatchewan sm 5E2 ABSTRACT One hundred-seven species belonging to 54 genera and 18 families of Ephemeroptera are reported from Saskatchewan.. An additional two species, Callibaetis skokianus Needham and Procloeon rivulare (Traver), are reported in the literature but their presence in Saskatchewan cannot be confrrmed. Twenty-seven species are reported from Saskatchewan for the first time: Acerpenna sp. A Jacobus and McCafferty, Baetis bicaudatus Dodds, B. bundyae Lehmkuhl, B. intercalaris McDunnough, Centroptilum album McDunnough, C. conturbatum McDunnough, Cloeon dipterum (Eaton), Plauditus cestus (Provonsha and McCafferty), P. gloveri McCafferty and Waltz, Procloeon ingens (McDunnough), Pro irrubrum Lowen and Flannagan, Pro sp. 1, Pro rufostrigatum (McDunnough), Pro simplex (McDunnough), Baetisca laurentina McDunnough, Brachycercus edmundsi Soldan, Caenis hilaris (Say), Cercobrachys cree Sun, Webb and McCafferty, Ephemerella needhami McDunnough, Eurylophella bicolor (Clemens), Serratella serrata (Morgan), S. tibialis (McDunnough), Leucrocuta maculipennis(Walsh), Asioplax edmundsi (Allen), Siphloplecton basale (Walker), Parameletus chelifer, and Siphlonurus sp. 1. Cercobrachys cree is new to science. Species-lev~l identification keys are provided for all known larvae, except for those ofLeptophlebia Westwood, and for all known adult males except for ~hose of Plauditus Lugo-Ortiz and McCafferty. Diagnostic characters useful for differentiating each species from other Saskatchewan species, selected references, Saskatchewan 11 distribution maps, biological notes, material examined, and illustrations of taxonomically important characters, are provided for each species. Three main faunal zones are observed: Saskatchewan River system, lentic,. and boreal forest. Within each ofthe faunal zones several sub-zones occur. The distribution patterns observed in mayflies correspond closely to those observed in other groups of aquatic insects, except that few montane species are present in the Cypress inlls. Some ofthe large river-specialist species ofmayflies present in pristine portions ofthe Saskatchewan River system have been extirpated from much oftheir North American range. Analetris eximia Edmunds, Macdunnoa nipawinia Lehmkuhl and Lachlania saskatchewanensis Ide are known from only a few NorthAmerican locations and should be considered 'rare'. Anepeorus rusticus McDunnough and Acanthamola pubescens Whiting and Lehmkuhl are endangered and possibly extinct. iii ACKNOWLEDGEMENTS I would like to thank my supervisor, Dr.D.M. Lehmkuhl for providing lab space, equipment, specimens and advice during the course ofthis study. The members ofmy supervisory committee, Drs. A. Davis and R. Randell, provided valuable advice and assistance on numerous occasions. My sincerest thanks go to Dr. Dale Parker for his friendship, advice, patience, field assistance, specimens, etc. There were many instances where it was Dale's encouragement alone that allowed .me to continue with this project. Without Dale's involvement this project would not have been possible. Dr. W.P. McCafferty ofPurdue University, Indiana verified specimens, provided unpublished data, and encouraged me to publish some ofmy results. To hith lowe many thanks. Mr. L. Sun ofPurdue University verified specimens ofBrachycercinae and graciously allowed me to use some ofhis drawings and SEM photographs of Cercobrachys cree. Mrs. S. Stacey contributed many excellent line drawings. Financial assistance was provided by the University of Saskatchewan and Saskatchewan Environment and Resource Management. Special thanks are given·to the Head ofthe Department ofBiology, Dr. V. Sawhney, for assisting me when the future ofmy funding was uncertain. Research funding ,was provided by the Northern Scientific Training.Program. iv My friends and family provided encouragement and support throughout my studies. In particular, M. Pollock, R. Tremaine, M. Wismer, S. McCartney, and my parents deserve thanks. v TABLE OF CONTENTS Page PERMISSION TO USE i ABSTRACT ~ ii ACKNOWLEDGMENTS iv TABLE OF CONTENTS vi LIST OF TABLES xii LIST OF FIGURES xiii 1. INTRODUCTION 1 1.1 Introductory Background .1 1.2 Previous Studies ofSaskatchewan Ephemeroptera 4 1.3 Objectives 5 1.4 Introduction to Mayfly Morphology 6 .1.4.1 Adult Characters 6 1.4.2 Larval Characters 10 1.5 Study Area '.' .13 2. METHODS ~ 17 2.1 Material Examined 17 2.2 Collection and Preservation ofSpecimens 17 2.3 Rearing 19 2.4 Illustrations 21 VI 2.5 Verification ofSpecies Identifications and Deposition ofSpecimens 21 2.6 Systematic Organization ~ .22 3. SYSTEMATICS 23 3.1 Families ofEphemeroptera ofSaskatchewan 23 3.1.1 Key to the Families ofMayflies: Larvae 23 3.1.2 Key to the Families ofMayflies: Adult Males 26 3.2 Acanthametropodidae 29 3.2.1 Analetris 30 3.3 Ameletidae ~ 32 3.3.1 Ameletus 32 3.4 Ametropodidae 35 3.4.1 Ametropus 36 3.5 Arthropleidae ~ ; 38 3.5.1 Arthroplea 38 3.6 Baetidae 39 3.6.1 Key to the Genera ofBaetidae: Larvae .40 3.6.2 Key to the Genera ofBaetidae: Adult Males 43 3.6.3 Acentrella '0' •••••••••45 3.6.4 Acerpenna 52 3.6.5 Apobaetis '" 56 3.6.6 Baetis ~ 58 3.6.7 Callibaetis 76 vii 3.6.8 Camelobaetidius 82 3.6.9 Centroptilum 84 3.6.10 Cloeon 91 3.6.11 Diphetor 94 3.6.12 Fallceon 96 3.6.13 Plauditus ~ 98 3.6.14 Procloeon 107 3.6.15 Pseudocloeon 121 3.7 Baetiscidae 125 3.7.1 Baetisca 126 3.8 Caenidae 129 3.8.1 Key to the Genera ofCaenidae: Larvae 130 3.8.2 Key to the Genera ofCaenidae: Adults 131 3.8.3 Brachycercus 131 3.8.4 Caenis 135 3.8.5 Cercobrachys 144 3.9 Ephemerellidae 145 3.9.1 Key to the Genera ofEphemerellidae: Larvae 146 3.9.2 Key to the Genera ofEphemerellidae: Adult Males 147 3.9.3 Dannella 148 3.9.4 Drunella ·151 3.9.5 Ephemerella 153 3.9..6 Eurylophella 158 viii 3.9.7 Serratella 162 3.10 Ephemeridae 165 3.10.1 Key to the Genera ofEphemeridae Larvae .165 3.10.2 Key to the Genera ofEphemeridae Adults 166 3.10.3 Ephemera 166 3.10.4 Hexagenia 168 3.11 Heptageniidae , ~170 3.11.1 Key to the Genera ofHeptageniidae: Larvae 171 3.11.2 Key to the Genera ofHeptageniidae: Adult Males 173 3.11.3 Acanthomola 175 3.11.4 Anepeorus ..............................................•................176 3.11.5 Cinygmula 178 3.11.6 Epeorus 179 3.11.7 Heptagenia ·.181 3.11.8 Leucrocuta 192 3.11.9 Macdunnoa 195 3.11.10 Nixe 197 3.11.11 Raptoheptagenia .204 3.11.12 Rhithrogena 206 3.11.13 Stenacron 208 3.11.14 Stenonema 211 3.12 Isonychiidae 218 3.12.1 Genus Isonychia 218 IX 3.13 Leptohyphidae ......................................................•...................220 3.13.1 Key to the Genera ofLeptohyphida: Larvae 221 3.13.2 Key to the Genera ofLeptohyphidae: Adult Males 221 3.13.3 Asioplax - ~ 221 3.13.4 Tricorythodes " 223 3.14 Leptophlebiidae 225 3.14.1 Key to the Genera ofLeptophlebiidae: Larvae 226 3.14.2 Key to the Genera ofLeptophlebiidae: Adult Males .; 226 3.14.3 Choroterpes ! •••227 3.14.4 Leptophlebia 228 3.14.5 Paraleptophlebia ~ 232 3.14.6 Traverella 237 3.15 Metretopodidae ' 239 3.15.1 Key to the Genera ofMetretopodidae: Larvae 239 3.15.2 Key to the Genera ofMetretopodidae: Adult Males 240 3.15.3 Metretopus ~ 240 3.15.4 Siphloplecton ' 241 3.160ligoneuriidae '," 245 3.16.1 Lach/ania 245 3.17 Polymitarcyidae , 247 3.17.1 Ephoron .........................................•.................. ~ 248 3.18 Pseudironidae 249 3.18.1 Pseudiron 250 x 3.19 Siphlonuridae 252 3.19.1 Key to the Genera ofSiphlonuridae: Larvae 252 3.19.2 Key to the Genera ofSiphlonuridae: Adult Males 252 3.19.3 Parameletus 253 3.19.4 Siphlonurus 254 4. DISCUSSION 258 4.1 Biogeography ofSaskatchewan Ephemeroptera 258 4.2 Potentially Threatened Species ofEphemeroptera 263 5. SUMMARY AND CONCLUSIONS ' 267 6. REFERENCES·CITED 269 APPENDIX 1. COLLECTORS NAMES 284 APPENDIX II: SAMPLE LOCATIONS 285 APPENDIX III. FIGURES REFERRED TO IN THE TEXT ~ 290 xi LIST OF TABLES Table AI. Names and initials ofcollectors 284 Table B1. Latitude and longitude coordinates for sample locations 285 xii LIST OF FIGURES Figure I. Adult characters, Ephemerella. 7 Figure 2. Larval characters, Ephemerella 11 Figure 3. Larval mouthparts, Ephemerella. 12 Figure 4. Approximate geographic boundaries ofSaskatchewan ecozones and ecoregions 16 Figure 5. Map ofSaskatchewan indicating locations from which mayfly specimens were examined~ 18 Figure 6. Rearing container 20 Figure 7. Rearing apparatus 20 Figure 8. Analetris· eximia, larva, dorsal view 290 Figure 9. Analetris eximia, fore wing 291 Figure 10. Ameletus oregonensis larva, abdominal sterna 6-8 291 Figure 11. Ameletus oregonensis, larval maxillae with pectinate spines indicated 292 Figure 12.