Revision of Nearctic Dasysyrphus Enderlein (Diptera: Syrphidae)
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Zootaxa 3660 (1): 001–080 ISSN 1175-5326 (print edition) www.mapress.com/zootaxa/ Monograph ZOOTAXA Copyright © 2013 Magnolia Press ISSN 1175-5334 (online edition) http://dx.doi.org/10.11646/zootaxa.3660.1.1 http://zoobank.org/urn:lsid:zoobank.org:pub:95ADD39C-98BE-4879-B070-34A5D86BD67B ZOOTAXA 3660 Revision of Nearctic Dasysyrphus Enderlein (Diptera: Syrphidae) MICHELLE M. LOCKE1,2,3 & JEFFREY H. SKEVINGTON1,2 1Canadian National Collection of Insects, Arachnids and Nematodes, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada Email: [email protected]; [email protected] 2Department of Biology, 209 Nesbitt Building, Carleton University, 1125 Colonel By Drive, Ottawa, Ont., Canada K1S 5B6 3Corresponding author Magnolia Press Auckland, New Zealand Accepted by D. Bickel: 8 Apr. 2013; published: 22 May 2013 Licensed under a Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0 MICHELLE M. LOCKE & JEFFREY H. SKEVINGTON Revision of Nearctic Dasysyrphus Enderlein (Diptera: Syrphidae) (Zootaxa 3660) 80 pp.; 30 cm. 22 May 2013 ISBN 978-1-77557-174-2 (paperback) ISBN 978-1-77557-175-9 (Online edition) FIRST PUBLISHED IN 2013 BY Magnolia Press P.O. Box 41-383 Auckland 1346 New Zealand e-mail: [email protected] http://www.mapress.com/zootaxa/ © 2013 Magnolia Press ISSN 1175-5326 (Print edition) ISSN 1175-5334 (Online edition) 2 · Zootaxa 3660 (1) © 2013 Magnolia Press LOCKE & SKEVINGTON Table of contents Abstract . 3 Introduction . 3 Materials and Methods . 6 Results . 18 Phylogenetic Analysis . 18 Species Concepts and Key . 23 Dasysyrphus Enderlein 1938 . 28 Key to Species of Nearctic Dasysyrphus Enderlein 1938 . 28 Taxonomy . 29 Dasysyrphus amalopis (Osten Sacken) . 29 Dasysyrphus creper (Snow) . 32 Dasysyrphus intrudens species complex (Osten Sacken) . 36 Dasysyrphus laticaudus (Curran) . 39 Dasysyrphus limatus (Hine) . 43 Dasysyrphus lotus (Williston) . 46 Dasysyrphus nigricornis (Verrall) . 48 Dasysyrphus occidualis Locke & Skevington sp. nov. 52 Dasysyrphus pacificus (Lovett) . 55 Dasysyrphus pauxillus (Williston) . 58 Dasysyrphus pinastri (DeGeer) . 62 Dasysyrphus richardi Locke & Skevington sp. nov. 64 Dasysyrphus venustus (Meigen) . 66 Discussion . 73 Acknowledgements . 77 References . 77 Abstract Dasysyrphus Enderlein (Diptera: Syrphidae) has posed taxonomic challenges to researchers in the past, primarily due to their lack of interspecific diagnostic characters. In the present study, DNA data (mitochondrial cytochrome c oxidase sub- unit I—COI) were combined with morphology to help delimit species. This led to two species being resurrected from syn- onymy (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. Key words: Diptera, Syrphidae, Dasysyrphus, revision, flower flies, hover flies, key, new species, Nearctic Region Introduction Dasysyrphus Enderlein 1938 is mainly a Holarctic genus. Thirty-six of the 43 currently recognized species are known to occur in North America, Europe and Asia, with eight species recorded from the Oriental region and one species recorded from the Neotropical region (some species occur in more than one region; Pape & Thompson 2010a). This is not an unusual distribution for a syrphine genus (Vockeroth 1969). Little is known about the biology of Dasysyrphus. The majority of biological information we have comes from studies done in Europe. No larvae are known from endemic Nearctic species and as a result only adult ecology can be discussed. Much of what is known from the Nearctic and what will be discussed has been gathered from specimen label data. Larvae are mottled, resemble bark and are easily recognized by a pair of long tapering projections on the anal segment, which help them to blend into their surroundings (Fig. 1A; Rotheray & Gilbert 2011; Rotheray 1993). They are known to be arboreal in both coniferous and deciduous trees (Rotheray 1993). Larvae are predatory and feed mainly on homopterans, but records of them feeding on other insects have been noted. Rojo et al. (2003) provide a catalogue to Dasysyrphus species and their larval prey. Their review of the literature suggests that the REVISION OF NEARCTIC DASYSYRPHUS Zootaxa 3660 (1) © 2013 Magnolia Press · 3 larvae feed mainly on Aphididae, but have been found feeding on Adelgidae, Diptera larvae, Neuroptera, Lepidoptera, Hymenoptera and Coleoptera. Rojo et al. (2003) also recorded the plant associations of these Dasysyrphus larvae and their prey. Most studies found these larvae associated with trees of the families Pinaceae, Aceraceae, Ulmaceae, Fagaceae and Rosaceae. Some studies reported finding Dasysyrphus larvae on woody shrubs in the families Fabaceae, Rosaceae and Celastraceae and a few other studies reported finding them on herbaceous plants in the families Brassicaceae and Chenopodiaceae (Rojo et al. 2003). Goeldlin de Tiefenau (1974) reported that larvae he reared in the lab wrapped themselves around a stem and remained in one position to feed until ready to pupate. This position allowed them to block the path and intercept prey as they passed by. Adults (Fig. 1B) are believed to be important pollinators. Their specific pollination habits are unknown but they are commonly found on flowers on sunny days. Most of the museum specimens observed have pollen grains stuck to their body hairs and in their gut. Adults have been recorded as visiting flowers of deciduous trees and smaller herbaceous plants (see Speight 2011). In the Nearctic region, specimens have been recorded as being collected from flowers of Prunus virginiana Linnaeus (Williston 1887) and Geranium Linnaeus (Snow 1895). While Dasysyrphus has been an understudied genus, a review of pollination in syrphids by Rotheray and Gilbert (2011) shows that the genera that have been studied are effective generalist pollinators. New data on flower visitation (from labels) is included in the species accounts below. Dasysyrphus are imperfect mimics, not exactly resembling any specific hymenopteran, but having the black and yellow colouration common to many Hymenoptera. Rotheray and Gilbert (2011) and Penney et al. (2012) provide overviews and discuss some hypotheses as to why this imperfect mimicry may exist in syrphids. Since Dasysyrphus larvae tend to be arboreal, the adults are typically found in or near forests. Speight (2011) reports in his European species accounts that the following species are found in mainly coniferous, but sometimes deciduous forests: D. albostriatus (Fallen 1817), D. eggeri (Schiner 1861), D. friuliensis (Goot 1960), D. hilaris (Zetterstedt 1843), D. lenensis Bagatshanova 1980, D. pauxillus (Williston 1887), D. pinastri (De Geer 1776), D. postclaviger (Stys & Moucha 1962), D. tricinctus (Fallen 1817) and D. venustus (Meigen 1822). Dasysyrphus nigricornis (Verrall 1873) is reported as being found in taiga (Neilsen 1998) and dwarf-shrub tundra, although much confusion exists over the name, so the full extent of its range and habitat are not known (Speight 2011). Fluke (1933) was the first author to define what would later be called Dasysyrphus and he provided higher level and species keys with descriptions of all Nearctic species. He defined this group as the amalopis group under the genus Metasyrphus Matsumura (in Matsumura and Adachi) 1917. He stated that he was not prepared to associate his four distinct groups of Metasyrphus with existing genera due to the confusion of some of the generic concepts in the Old World and lack of material from the Old World to compare his specimens to. Dasysyrphus was erected as a subgenus of Syrphus Fabricius 1775 in 1938 by Enderlein. The type species is D. albostriatus. Enderlein distinguished Dasysyrphus from the rest of the Syrphus group by the conspicuously dense hair on its eyes (a character now known to be shared with other syrphine genera). Dasysyrphus has a similar habitus to many other genera in the subfamily Syrphinae, having yellow spots or stripes on a black abdomen. Enderlein included 16 species in his new genus and described two more from the Palaearctic, Oriental and Afrotropical regions, although all seven species from the Oriental and Afrotropical regions and three from the Palaearctic have now been placed in other genera. Enderlein did not include any Nearctic species in Dasysyrphus. The Nearctic species were first placed in Dasysyrphus in 1965 when Stone et al. published “A Catalog of the Diptera of America North of Mexico”. They referenced the Metasyrphus amalopis group of Fluke (1933) for the species that they included in Dasysyrphus. Vockeroth (1992) provided two keys to the seven Canadian, Alaskan and Greenlandic species of Dasysyrphus and species descriptions. No other recent revisionary work has been done. The first species of Dasysyrphus to be described was Musca pinastri De Geer 1776, from Europe. De Geer provided a description of the larvae and adults of this species and provided some ecological observations as well. De Geer was also one of the few authors to provide illustrations of the specimens