The Tabanidae (Diptera) of Oregon
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AN ABSTRACT OF THE THESIS OF ALI AHMED MAHMOUD for the degree of DOCTOR OF PHILOSOPHY in ENTOMOLOGY presented on August 20, 1979 Title: THE TABANIDAE (DIPTERN OF OREGON / Abstract approved: Redacted for privacy John D. Lattin Fifty species and subspecies and six varieties in eight genera of the family Tabanidae are recognized from Oregon. The following genera are represented in Oregon: Apatolestes Williston, Pilimas Brennan, Stonemyia Brennan, Silvius Meigen, Chrysops Meigen, Atylotus Osten Sacken, Hybomitra Enderlein and Tabanus Linnaeus. Adults and larvae were collected from various parts of Oregon. A Malaise trap baited with carbon dioxide gas was used for the collection of adults. Materials in the collections of Oregon State University and other institutions in and outside Oregon were examined. General information on the biology and morphology of the various life stages are presented. Zoogeographical information, as given here, includes distribution and analysis of the Oregon fauna. Over 3,000 specimens were examined. A description of each species is given together with label data of examined specimens, a discussion of the taxonomy, distribution and immature stages. Difficulties were encountered with some species of Hybomitra, including H. sonomensis (Osten Sacken) and H. fulvilateralis (Macquart). The status of these species is not clear since some of the characters used in the separation of tabanid species are subject to considerable variation. This problem is discussed in the conclusion of this study and under each appropriate species. Tabanus fratellus Williston is removed from the subgenus Glaucops Zsilady and placed in the subgenus Tabanus Linnaeus, since some specimens have four annulated antennae. Hybomitra hirtula (Bigot) is treated as a full species on the basis of consistently denuded sub- callus that separates it from H. tetrica (Marten). H. phaenops Osten Sacken is also treated as full species rather than as variety of H. sonomensis Osten Sacken because they differ ina number of characters. The Tabanidae (Diptera) of Oregon by Ali Ahmed Mahmoud A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Completed August 1979 Commencement June 1980 APPROVED: Redacted for privacy Profess of Entomology in charge of major Redacted for privacy Chairman of Department of Entomology el Redacted for privacy Dean of GidUate School Date thesis is presented August 20, 1979 Typed by Joyce E. McEwen for Ali Ahmed Mahmoud ACKNOWLEDGEMENTS I would like to express my thanks and gratitude to the Director of the National Health Laboratory, Ministry of Health, Government of the Sudan, who granted the fellowship and who allowed the time and finan- cial support for this study. The World Health Organization (WHO), Mediterranean Regional Office, Alexandaria, Egypt provided financial support. Mrs. Susan Shanley of the WHO American Regional Office, Washington, D.C., administered the program in a very efficient and smooth manner. My major professor, Dr. John D. Lattin, has always been a source of help and encouragement. He contributed many thoughtful ideas and concerned himself with my problems both inside and outside the scope of this study. I am very much indebted and grateful to him. Many thanks are due to Dr. Paul Oman who spent considerable time discussing matters pertaining to this study and made his rich collection of reprints available to me.I thank Dr. Norman H. Anderson, Dr. Robert L. Goulding, Dr. James D. Hall, Dr. Paula Kanarek, Dr. Gary L. Zimmerman, the members of my committee, for their time, patience and useful ideas and suggestions. Dr. Wayne Mathis (Smithsonian Institution, United States National Museum, Washington, D.C.) helped me in various ways and made things easier for me during my first year on the campus. I am very thankful to him. I am also thankful to the following persons from Oregon State University; Mr. Vincent Razafimahatratra for taking the photographs and helping with the drawings and to Mrs. Bonnie Hall for her technical advice; Mr. Neil Cobb for bringing in the collections from Portland and contributing his own material; Mr. Gary Cooper for reading part of the thesis and Mr. Gary Peters who made his personal collection avail- able to me. I am indebted to Dr. Robert Lane, California State Department of Health, Berkeley, California, for his suggestions on lines of research and also the identification of the larvae; Dr. L.L. Pechuman, Cornell University, Ithaca, N.Y., for his encouragement, discussions and ideas in several areas and the identification of adult specimens; Dr. C.B. Philip, California Academy of Science, San Francisco, California, for his encouragement, ideas and specimens. Dr. H.J. Teskey, Biosystematics Research Institute, Canada Agriculture, Ottawa, Canada, for his assistance and Dr. William Turner, Washington State University, Pullman, Washington, for useful discussion, encouragement and contribu- tions of data and specimens. Special thanks are due to Dr. Paul Arnaud, California Academy of Science, San Francisco, who kindly loaned many specimens and allowed me to examine the collection during my visit. Thanks are also due to the following persons and institutions which allow me to examine specimens in their collections: California State Department of Agriculture, Sacramento, California, Dr. Fred Andrews; Oregon State Department of Agriculture, Salem, Oregon, Mr. Richard Westcott and Mr. Robert Brown; United States Department of Agriculture, Fresno, California, Dr. W.M. Rogoff; United States National Museum, Washington, D.C., Dr. F.C. Thompson; University of California, Berkeley, Dr. J. Powell; University of California, Davis, Dr. R.O. Schuster; University of. Idaho, Moscow, Dr. W.F. Barr; and Washington State University, Pullman, Dr. William Turner. The following persons and institutions have kindly loaned their collections: Dr. Marvin Caffey, Southern Oregon State College, Ashland; Dr. George Runyan, Oregon State Department of Health, Portland; Portland State University, Portland. I am very much thankful to my wife, Fatimah, for her various help and her patient and continuous encouragement, her endurance and tolerance for the children during my many absences. TABLE OF CONTENTS Page INTRODUCTION 1 LITERATURE REVIEW 3 MATERIAL AND TECHNIQUES 6 Field Collection 6 Laboratory Procedures 7 Areas of Intensive Collection of Tabanidae in Oregon . 8 BIOLOGY 12 Life Cycle 12 Natural Enemies 14 Economic Importance 15 Sequential Baited Malaise Trap Collections 17 ZOOGEOGRAPHY 20 Distribution in the Nearctic Region 21 Geography of Oregon 21 Analysis of the Tabanid Fauna of Oregon 24 MORPHOLOGY AND TAXONOMIC CHARACTERS 29 External Morphology 29 Evaluation of Taxonomic Characters 31 TAXONOMY 33 Evolution 33 Position of Tabanidae in The Diptera 34 Classification of the Family Tabanidae 35 FAMILY TABANIDAE 36 Classification of Oregon Tabanidae 37 SUBFAMILY PANGONIINAE 39 Genus Apatolestes Williston 39 Key to the Females of Oregon Apatolestes 40 Apatolestes albipilosus Brennan 41 Apatolestes comastes Williston 42 Genus Pilimas Brennan 46 Pilimas californicus (Bigot) 48 Genus Stonemyia Brennan 51 TABLE OF CONTENTS (Continued) Page Stonemyia tranquilla fera (Williston) 52 SUBFAMILY CHRYSOPSINAE 56 Genus Silvius Meigen 56 Key to the Females of Oregon Silvius 58 Subgenus Silvius Meigen 58 Silvius (Silvius) gigantulus (Loew) 58 Subgenus Griseosilvius Philip 63 Silvius (Griseosilvius) notatus (Bigot) 63 Subgenus Zeuximyia Philip 65 Silvius (Zeuximyia) philipi Pechuman 65 Genus Chrysops Meigen 67 Key to the Females of Oregon Chrysops 69 Chrysops aestuans van der Wulp 71 Chrysops asbestos Philip 74 Chrysops bisho i Brennan 77 Chrysops co oradensis Bigot 80 Chrysops discalis Williston 84 Chrysops excitans Walker 88 Chrysops furcatus Walker 91 Chrysops mitis Osten Sacken 93 Chrysops noctifer noctifer Osten Sacken 96 Chrysops noctifer pertinax Williston 99 Chrysops proclivis Osten Sacken 105 Chrysops surdus Osten Sacken 110 Chrysops wileyae Philip 113 SUBFAMILY TABANINAE 116 Genus Atylotus Osten Sacken 116 Key to the Females of Oregon Atylotus 118 Atylotus incisuralis (Macquart) 118 Atylotus tingaureus (Philip) 123 Genus Hybomitra Enderlein 126 Key to the Females of Oregon Hybomitra 128 Hybomitra aasa Philip 131 Hybomitra astuta (Osten Sacken) 134 Hybomitra atrobasis (McDunnough) 136 Hybomitra californica (Marten) 140 Hybomitra captonis (Marten) 144 Hybomitra epistates (Osten Sacken) 149 Hybomitra frontalis (Walker) 152 Hybomitra fulvilateralis (Macquart) 153 Hybomitra hirtula (Bigot) 157 Hybomitra lanifera (McDunnough) 160 Hybomitra melanorhina (Bigot) 162 TABLE OF CONTENTS (Continued) Page Hybomitraopaca (Coquillett) 165 Hybomitraphaenops (Osten Sacken) 168 Hybomitraprocyon (Osten Sacken) 171 Hybomitrarhombica (Osten Sacken) 174 Hybomitraru estris (McDunnough) 180 Hybomitrasequax Williston) 183 Hybomitrasonomensis (Osten Sacken) 186 Hybomitratetrica (Marten) 192 Hybomitrazygota (Philip) 196 Genus Tabanus Linnaeus 199 Key to the Females of Oregon Tabanus 201 Tabanus aegrotus Osten Sacken 203 Tabanus fratellus Williston 206 Tabanus kesseli Philip 209 Tabanus laticeps Hine 212 Tabanus monoensis Hine 215 Tabanus punctifer Osten Sacken 217 Tabanus similis Macquart 222 Tabanus stonei Philip 226 Tabanus tetropsis Bigot 228 CONCLUSIONS 232 LITERATURE CITED 235 LIST OF FIGURES Page la. Site of tabanid collection on Mary's Peak 245 lb. A malaise trap baited with CO2, on operation 245 2-4. Heads of species representing the three subfamilies 247 5-6.