Investigation of Aleochara Bipustulata (Coleoptera: Staphylinidae) Adult Diet and Community Interactions
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Investigation of Aleochara bipustulata (Coleoptera: Staphylinidae) adult diet and community interactions by Lars David Andreassen A thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment of the requirements of the degree of Doctor of Philosophy Department of Entomology University of Manitoba Winnipeg Copyright © 2013 L.D. Andreassen 2013 Abstract Lars Andreassen The exotic cabbage maggot (CM) infests canola on the prairies, feeding on roots in its larval stage, which disrupts the uptake of nutrients and water and provides an entry point for fungal plant pathogens. The European staphylinid, Aleochara bipustulata L., may be introduced for control of CM, but only if the risk to other species is low and if A. bipustulata has demonstrable potential to increase mortality already caused by natural enemies in Canada. Aleochara bipustulata could contribute to pest management as a predator of CM eggs and larvae, and as a parasitoid of CM puparia; however, it could affect non-pest species in the same two ways. A variety of invertebrates that share the soil of Brassica fields with immature CM were screened in laboratory no-choice assays to determine what adult A. bipustulata eat. In these assays, immobile or barely mobile invertebrates were accepted regularly and could be at risk. The majority of groups were seldom or never consumed. Also, a molecular assay developed to test for CM DNA in the guts of field-collected A. bipustulata revealed its high potential as a predator, and a similar assay developed for two carabid beetle species showed these to be seldom if ever consumed. Laboratory and field cage assays with other CM egg predators showed A. bipustulata has potential to disrupt other species, particularly the closely related A. bilineata Gyllenhal, as they seem to forage in similar microhabitats. Measurements of field-collected beetles indicate CM is unlikely to be the primary host in Europe, so introducing A. bipustulata to Canada may bring risks to non-target Diptera species. This was observed even though a series of laboratory experiments demonstrated CM is a superior and preferred host relative to the smaller, acalyptrate cheese skipper. ii Acknowledgements Thanks to my major supervisor, Dr. Neil Holliday, for his guidance, encouragement, support and mentorship throughout the study and for his critical commentary on my thesis. I wish to thank Dr. Ulli Kuhlmann for his guidance, encouragement and support as well. My other committee members, Drs. Terry Galloway, Peter Mason, and Steve Whyard all contributed their ideas and support as well, and for this I am grateful. Tim Haye was helpful and generous with his time and input. The same is true of Aditi Singh, Cass Erdelyn, and Darcy Childs. Alicia Leroux contributed an enormous amount of time and encouragement as well, and I thank her very much. Thanks also to many others for their contributions: Kathy Graham, Lisa Babey, Dave Holder, Sharon Surowiec, Justin Crowe, Daryl Wright, Jenny Lazebnik, Paul Abrams, Jamie McKeen, Chandra Moffat, Roberto Duarte, Jake Miall, and Andrea Brauner. Thanks for taxonomic assistance to Frederic Beaulieu, Henri Goulet, and Tarek Tantawi (Agriculture and Agri-Food Canada, Ottawa); Michelle Glasstetter (University of Basel); Andreas Wohltmann (University of Bremen); Ambrose Hänggi (Basel Natural History Museum); and Henrik Enghoff (Natural History Museum of Denmark). The financial support of my parents, Western Grains Research Foundation, CABI, the Government of Canada (Agriculture and Agri-Food Canada; Natural Science and Engineering Research Council), the Government of Manitoba (Agriculture and Rural Development Initiatives), and the Canola Council of Canada are gratefully acknowledged. Thanks finally to Nick Mills for agreeing to serve as my external examiner. iii Table of Contents Abstract ........................................................................................................................... ii Lars Andreassen .............................................................................................................. ii Acknowledgements ........................................................................................................ iii Introduction ......................................................................................................................... 1 Chapter 2 ......................................................................................................................... 5 Literature Review............................................................................................................ 5 Classical biological control ......................................................................................... 7 Delia radicum, an exotic pest of prairie canola ........................................................ 17 Aleochara bipustulata, candidate for introduction to the prairies ............................ 23 Research Objectives ...................................................................................................... 29 Chapter 3 Section 1 ....................................................................................................... 31 Investigations of diet in adult Aleochara bipustulata .................................................... 31 Introduction ............................................................................................................... 32 Materials and Methods .............................................................................................. 35 Results ....................................................................................................................... 43 Discussion ................................................................................................................. 47 Chapter 3 Section 2 ....................................................................................................... 63 Predation of Delia radicum eggs by three epigaeic beetle species ............................... 63 Introduction ............................................................................................................... 64 Materials and Methods .............................................................................................. 66 Results ....................................................................................................................... 73 Discussion ................................................................................................................. 76 Chapter 3 Section 3 ....................................................................................................... 93 The resource utilization niche of two rove beetle parasitoids of Diptera: host species, host size, and depth ....................................................................................................... 93 Introduction ............................................................................................................... 94 Materials and Methods .............................................................................................. 97 Results ..................................................................................................................... 102 Discussion ............................................................................................................... 107 Chapter 3 Section 4 ..................................................................................................... 129 Host selection preferences and some of their consequences in Aleochara bipustulata ..................................................................................................................................... 129 Introduction ............................................................................................................. 130 Material and Methods ............................................................................................. 134 Results ..................................................................................................................... 142 Discussion ............................................................................................................... 145 Chapter 4 ..................................................................................................................... 164 General Discussion ..................................................................................................... 164 iv List of Tables Table 1. Taxonomy, origin, and mass of organisms exposed in No-choice tests to determine Aleochara bipustulata’s fundamental host range. ........................................... 52 Table 2. Oligonucleotide primers employed in this study, with optimized annealing temperatures (Ta) and product size. .................................................................................. 54 Table 3. Species used to confirm specificity of primers designed for amplification of Delia radicum, Amara similata, and Bembidion quadrimaculatum cytochrome oxidase I. ........................................................................................................................................... 55 Table 4. Activity-density of adult Aleochara bipustulata in Swiss cabbage fields sampled 2009–11, densities of Delia radicum in the same fields, and proportions of A. bipustulata that tested positive for D. radicum DNA in PCR assays. ................................................. 56 Table 5. Statistics and model parameters