Factors influencing bee pollinator bycatch in cutworm and armyworm moth (Lepidoptera: Noctuidae) monitoring programs in Alberta, Canada

• Author / Creator

  Grocock, Nicholas L

• Unintentional bycatch of bee pollinators in monitoring traps that target moth pests occurs in many agroecosystems. Capture of bees can have a substantial effect on the efficiency of monitoring systems and has the potential to negatively impact bee biodiversity and pollination services for both crops and wild flowering plants. As there is widespread evidence of global pollinator declines, which are largely driven by anthropogenic stressors, it is important to reduce the systematic removal of bees. In this thesis, multiple approaches were used to investigate bumble bee (Hymenoptera: Apidae) and other wild bee bycatch in green-coloured Unitraps baited with a variety of semiochemical lures. First, we examined bee attraction to traps baited with synthetic pheromones of both cutworm and armyworm moths (Lepidoptera: Noctuidae) and food bait lures in the field over three growing seasons. Electrophysiological assays tested the antennal response of bees to components of the signals tested in the field. The composition of bycatch in pheromone-baited Unitraps was dominated by bumble bees, and largely by one species, Bombus rufocinctus Cresson. Few other wild bees or managed honey bees, Apis mellifera L. (Hymenoptera: Apidae), were captured during this study. Food bait lures that were composed of fermentation by-products were not attractive to bees in this study, however the addition of the floral volatile phenylacetaldehyde increased attraction to food baits. As food bait lures are generally unattractive to bee pollinators, they may be a valuable tool for monitoring noctuid moth populations in the Canadian Prairies. Additionally, we provide the first evidence that Bombus spp. can detect moth pheromone components, which provides insights into the mechanism of this attraction. Second, we examined the response of wild bees to monitoring traps baited with synthetic sex pheromone of bertha armyworm, Mamestra configurata Walker (Lepidoptera: Noctuidae), across a large area of canola production in Alberta and evaluated the effect of environmental variables on bee bycatch. As in the first study, B. rufocinctus was the most numerous species captured and few other bees were attracted to monitoring traps. We found that bertha armyworm sex pheromone-baited traps positioned in the Peace region of Northwestern Alberta had the highest bumble bee bycatch, which is likely linked to the large area of forested habitat area in the region. Local flowering plant abundance did not directly impact bee bycatch but was influential for the overall model fit. The proportion of agricultural landcover in the area surrounding monitoring traps had a negative effect on the number of bees captured, which was likely due to less natural and semi-natural habitat in those regions. Finally, we provide recommendations to reduce the bycatch of beneficial bee pollinators in monitoring networks that target lepidopteran pests, which are a necessary component of successful agriculture in the Prairie Provinces.

• Subjects / Keywords

  • Pheromone
  • Bycatch
  • Hymenoptera
  • Pollinator
  • Monitoring

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-4wnw-6d63

• License

  Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.