Biological studies of a European fruit fly, Euphranta connexa (Diptera: Tephritidae), a candidate biological control agent for invasive swallow-worts By Alicia M. Leroux A Thesis submitted to the Faculty of Graduate Studies of The University of Manitoba in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE Department of Entomology University of Manitoba Winnipeg, Manitoba © Alicia M. Leroux 2014 ABSTRACT The biology of Euphranta connexa was investigated to assess its potential as a biological control agent for introduction in North America against the invasive weeds Vincetoxicum rossicum (Kleopow) and V. nigrum (L.) (Apocynaceae). A range of temperatures suitable for development was determined for the pupal and egg stages of E. connexa. The pupa is the overwintering stage of E. connexa and does not exhibit a diapause, but undergoes a cold induced quiescence. The relationship of temperature to pupal developmental was investigated and did not differ among insects from sites over a range of altitude of 1300 m, indicating E. connexa may not be locally adapted. When adult female E. connexa emerged from pupae they had not developed eggs but 10 to 15 days later they had a full complement of developed eggs. Mating of E. connexa did not affect the egg load of females but egg load was reduced in females that had spent longer as pupae in cold conditions. There was evidence that females could resorb previously developed eggs. In surveys for larval and larval-pupal parasitoids of E. connexa infested seedpods of V. hirundinaria from three countries, there were a total of 1599 parasitoids from eight Hymenoptera families,and most parasitoids were Braconidae. Prior to the survey, the fruit midge, Contarinia asclepiadis (Diptera: Cecidomyiidae) was considered rare, but it was found in seedpods from all collection sites in Switzerland and infested about 9.2% of seedpods at two localities in 2013. Of 13 parasitoid morphospecies found in the survey, two braconid and one ichneumonid morphospecies were frequent and were parasitoids of E. connexa, three platygastrid morphospecies were probably parasitoids of C. asclepiadis, and three morphospecies were probably hyperparasitoids. The thesis research will allow 1 development of effective methods for studying impact and host range of E. connexa, studies that are required to assess the potential as a biological control agent against V. rossicum and V. nigrum. 2 ACKNOWLEDGEMENTS I would like to start by thanking Dr. Holliday for his time and patience. His support and drive to see his students improve and succeed have helped me through both my undergraduate and graduate careers. Andre Gassman provided a healthy work place balanced with pragmatism and humor that was needed and welcomed through the duration of my thesis. Other members of CABI I would like to thank are Hariet Hinz for her constructive feedback and Ulli Kuhlmann for his help in developing collaboration between CABI and the University of Manitoba that has made my thesis possible. The entire committee provided me with freedom that was difficult at times but provided me with a chance to establish myself in my field. I would like to thank the many students at CABI for providing assistance over the years that helped aid me in my thesis: Maja Penic, Meaghan Bennett, Janine Brooke, Ariel Firebaugh, Emily Palmer, Clesson Higashi, Cornelia Closa, Sara Abdallah, and Léna Durocher-Granger. Special thanks go to Alyson Carter, Letitia de Ros, Sean Pablo, and Matt Wahlberg for all the support and understanding. Thank you to my many office mates over the years that were always accepting, offering support and keeping quiet about the collection of coffee mugs always present around my space. My parents were a constant and necessary support and without them, finishing this degree would have been difficult, if not impossible. They helped maintain my life in Canada while trying to understand my field. 3 Table of Contents ABSTRACT ......................................................................................................................... 1 ACKNOWLEDGEMENTS ................................................................................................. 3 LIST OF TABLES ............................................................................................................... 7 LIST OF FIGURES ............................................................................................................. 9 CHAPTER 1: INTRODUCTION ...................................................................................... 11 CHAPTER 2: LITERATURE REVIEW ........................................................................... 13 Negative effects of invasive plants ............................................................................. 13 Management of invasive plants .................................................................................. 15 Classical biological control of invasive plants by insects .............................................. 16 Benefits of classical biological control ....................................................................... 17 Risks of classical biological control ........................................................................... 18 Elements required for release of a classical biological control agent ......................... 20 Selection of a target weed ........................................................................................... 20 Establishing a list of potential biological control agents ............................................ 21 Potential agent assessment .......................................................................................... 21 Taxonomy .............................................................................................................. 21 Current and expected geographic distribution ....................................................... 22 Agent population source ........................................................................................ 22 Host range .............................................................................................................. 22 Life history ............................................................................................................. 23 Natural enemies ..................................................................................................... 23 Insect handling ....................................................................................................... 23 Host specificity ...................................................................................................... 24 Impacts once control agents are released ............................................................... 25 Post release monitoring .......................................................................................... 26 Vincetoxicum spp. and Euphranta connexa study system .............................................. 26 Taxonomy of Vincetoxicum spp. ................................................................................ 26 Distribution and habitat requirements of Vincetoxicum spp. in Europe ..................... 27 Distribution and habitat requirements of Vincetoxicum spp. in North America......... 28 Biology of Vincetoxicum spp. ..................................................................................... 30 Effects of Vincetoxicum spp. in North America ......................................................... 32 Euphranta connexa ........................................................................................................ 34 Taxonomy of Euphranta connexa .............................................................................. 34 Life history of Euphranta connexa ............................................................................. 34 4 Natural enemies affecting Euphranta connexa........................................................... 36 Host plant interactions of Vincetoxicum hirundinaria and Euphranta connexa ........ 37 Current status of the Vincetoxicum spp. biological control program ............................. 38 Research needed to assess Euphranta connexa .............................................................. 41 CHAPTER 3: EFFECTS OF TEMPERATURE ON PUPAL AND EGG DEVELOPMENT IN EUPHRANTA CONNEXA (DIPTERA: TEPHRITIDAE) AND IMPACTS FOR BIOLOGICAL CONTROL .................................................................... 45 Abstract .......................................................................................................................... 45 Introduction .................................................................................................................... 46 Materials and methods ................................................................................................... 48 Adult development...................................................................................................... 48 Egg development ........................................................................................................ 51 Results ............................................................................................................................ 53 Adult development...................................................................................................... 53 Egg development ........................................................................................................ 55 Discussion .....................................................................................................................