Diptera: Syrphidae)
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A revision of Nearctic Dasysyrphus (Diptera: Syrphidae) Michelle Mary Locke A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Biology Carleton University Ottawa, Ontario ©2012 Michelle Mary Locke Library and Archives Bibliotheque et Canada Archives Canada Published Heritage Direction du Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-91543-1 Our file Notre reference ISBN: 978-0-494-91543-1 NOTICE: AVIS: The author has granted a non L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distrbute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. 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Canada Abstract Dasysyrphus Enderlein (Diptera: Syrphidae) has posed taxonomic challenges to researchers in the past, due to their low interspecific variation. In the present study, DNA data (mitochondrial cytochrome oxidase c subunit I) were combined with morphology to help sort out species concepts. This led to two species being resurrected from synonymy (D. laticaudus and D. pacificus) and the discovery of one new species (D. occidualis sp. nov.). An additional new species was described based on morphology alone (D. richardi sp. nov.), as the specimens were too old to obtain COI. Part of the taxonomic challenge presented by this group arises from missing type specimens. Neotypes are designated here for D. pauxillus and D. pinastri to bring stability to these names. An illustrated key to 13 Nearctic species is presented, along with descriptions, maps and supplementary data. A phylogeny based on COI is also presented and discussed. ii Acknowledgements Funding support was provided by grants to J.H. Skevington (NSERC- CANPOLIN, NSERC Discovery, and Agriculture and Agri-Food Canada) and scholarships to me (Carleton University Faculty of Graduate Studies and Research Travel Bursaries). Thank you to J.H. Skevington and Agriculture and Agri-Food Canada for providing me with the resources and equipment required to complete this project and to the Biodiversity Institute on Ontario for DNA barcoding support. Thank you to the insect collection managers who graciously provided me with specimens for study. Also to E. Proctor, P. Laska, T. Neilsen, W. van Steenis, M. Hauser for specimens. Thanks to S. Kelso for his guidance in the molecular lab, to W. Knee for his help with the Bayesian analysis, to A. Young for putting up with me during all of our field work (and making me drive up a treacherous mountain to find a rare fly!), to D. Doczkal for advice on Dasysyrphus. I would like to thank Vladimir Davydov for the beautiful photograph of the Dasysyrphus larva and A. Young for the photograph of the adult (Figure 1). I would like to give a special thank you my parents, Dave and Karen, whose love and support have helped make this possible. Also, my sister, Stephanie, brother Sean, and best friends, Emily and Heather for their words of encouragement, which always put a smile on my face. Thank you. iii Table of Contents List of Tables v List of Figures v 1 introduction 1 1.1: Species Concepts 1 1.2: What is Dasysyrphus? 5 1.3: Zoogeography 8 1.4: Biology 9 1.5: History of Dasysyrphus Taxonomy 11 2: Materials and Methods 14 3: Phylogenetic Analysis 21 3.1 Results of Analyses 22 3.2 Discussion of Analyses ...24 4: Species Concepts and Key 32 4.1 Generic Redescription 32 4.2 Key to Species 35 4.3 Species Descriptions 39 4.4 Discussion 165 References : 169 Tables 180 Figures 188 iv List of Tables Table 1: Voucher information for molecular Dasysyrphus specimens 180 Table 2: Intraspecific variation and nearest neighbour values 187 List of Figures Fig. 1: Dasysyrphus larva and adult field photographs 188 Fig. 2: Semi-strict consensus tree from Parsimony analysis 189 Fig. 3: Majority rule consensus tree from Bayesian analysis 190 Fig. 4: Neighbour-Joining tree 191 Fig. 5: Dasysyrphus amalopis and D. creper dorsal and lateral habitus 195 Fig. 6: Dasysyrphus intrudens complex dorsal and lateral habitus 196 Fig. 7: Dasysyrphus nigricornis and laticaudus dorsal and lateral habitus 197 Fig. 8: Dasysyrphus venustus and D. limatus dorsal and lateral habitus 198 Fig. 9: Dasysyrphus lotus and richardi dorsal and lateral habitus 199 Fig. 10: Dasysyrphus occidualis and D. pacificus dorsal and lateral habitus 200 Fig. 11: Dasysyrphus pauxillus and D. pinastri dorsal and lateral habitus 201 Fig. 12: Dasysyrphus amalopis and D. occidualis lateral genitalia 202 Fig. 13: Dasysyrphus creper and D. limatus lateral genitalia 203 Fig. 14: Dasysyrphus lotus and D. nigricornis lateral genitalia 204 Fig. 15: Dasysyrphus laticaudus and D. pacificus lateral genitalia 205 Fig. 16: Dasysyrphus pauxillus and D. pinastri lateral genitalia 206 Fig. 17: Dasysyrphus intrudens complex and D. venustus lateral genitalia 207 Fig. 18: Dasysyrphus amalopis and D. creper range map 208 v Fig. 19: Dasysyrphus intrudens complex range map 209 Fig. 20: Dasysyrphus laticaudus and D. richardi range map 210 Fig. 21: Dasysyrphus limatus range map 211 Fig. 22: Dasysyrphus lotus and D. nigricornis range map 212 Fig. 23: Dasysyrphus occidualis range map 213 Fig. 24: Dasysyrphus pacificus range map : 214 Fig. 25: Dasysyrphus pauxillus and D. pinastri range map 215 Fig. 26: Dasysyrphus venustus range map 216 vi Chapter 1: Introduction 1.1: Species Concepts The concept of a species is something that is widely debated in the scientific community, and has been for years. "No one definition has satisfied all naturalists; yet every naturalist knows vaguely what he means when he speaks of a species" (Darwin 1859). It is becoming more widely understood that biologists actually share a common concept of species. They can regularly discuss species without referencing the concept of species, and typically disagreement over a species does not usually arise unless specific species concepts are referred to in the discussion (Hey 2006). Over the years many species concepts have been proposed, some more widely accepted than others, and there is no consensus as to which one should be used (Hey 2006; De Queiroz 2007). The reason this matter is of such great debate is that the species is the fundamental unit in biology and has been likened to an atom in the field of physics (Du Rietz 1930; Mayr 1942; De Queiroz 2005). The species is the unit of study for many biologists, including systematists, ecologists, behaviourists, physiologists, evolutionary biologists, palaeontologists, geneticists and molecular biologists (De Queiroz 2005). Many scientific studies are based on what someone has identified as a species. The most broadly recognized concept of species comes from Ernst Mayr (1942). He defined his Biological Species Concept (BSC) as "groups of actually or 1 potentially interbreeding populations, which are reproductively isolated from other such groups". While widely used, there are many times when this definition is sometimes impossible and often impractical to apply. It does not work in the case of asexually reproducing organisms or sexual organisms that hybridize, as many plants and animals do (Simpson 1951). It is also not feasible to apply this concept when studying fossils or museum specimens that include little to no ecological data. In insect taxonomy, we rarely have data to delimit species based on concepts that require ecological and/or biological data. Hennig (1966) recognized that the BSC did not account for the evolution of species through time and reproductive barriers could not exist as one species evolved from another so he proposed the Phylogenetic Species Concept (PCS). Over time this concept has been gradually refined and is currently defined as "...the smallest aggregation of (sexual) populations or (asexual) lineages diagnosable by a unique combination of character states" (Wheeler & Platnick 2000). There is no subdivision of species into subspecies, therefore the PSC diagnoses more species than the BSC, which allows for subspecies (Dillon & FjeldsS 2005). Many other concepts have been put forth throughout the years (see Table 1 in De Queiroz 2007), each providing new and different criteria for delimiting species. The reason so many concepts exist is due to the fact that there are so many Hicrinlinpc in "hinlncrv fn<a On^irnT 9007^ Nirhpc arp imnnrfant fn an prnlncjict- genes to a geneticist and diagnosable morphological characters to some 2 taxonomists. One can expect each field to value the criteria it studies, placing it as the most significant tool in species diagnoses and delimitation (De Queiroz 2007).