Characterization of the pheromone communication channel in Mamestra configurata, the bertha armyworm
Date
2020-01-23
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0001-8190-1051
Type
Thesis
Degree Level
Doctoral
Abstract
The bertha armyworm (BAW), Mamestra configurata, is one of the major insect pests feeding on a wide range of plant species, including canola, across western Canada. The components of the sex pheromone blend specific to M. configurata were identified in the 1970’s and are currently used in the pheromone trap monitoring system. However, there is evidence that geographic BAW populations develop at different rates and respond differently to the commercially prepared pheromone lures which affects our ability to accurately predict economic infestation levels for this pest. Collection of egg masses and pupae from several western Canada locations during the last BAW outbreak (2011-2014) presented a rare opportunity to investigate the genetics and biology of pheromone communication in M. configurata in field populations as compared to the long-term laboratory reared strain. My research encompassed aspects of both female pheromone production and male response to the female produced signal. I utilized next generation sequencing combined with bioinformatic analysis to identify and characterize genes involved in pheromone biosynthesis in females and chemosensory proteins involved in pheromone reception in males and females. I also used a novel single nucleotide polymorphism identification strategy to characterize genetic variation within pheromone specific chemosensory gene sequences among males from three BAW populations. The female pheromone gland analysis via gas chromatography coupled mass spectroscopy indicated that although, the amount of major and minor pheromone components varied greatly between individuals within a population, the pheromone blend ratios were not found to be significantly different between the two subpopulations investigated. Behavioural assays in the wind tunnel showed a marked difference in the ability of colony reared BAW males to take flight and reach the pheromone source as compared to field population males. Electrophysiological recordings obtained from colony and field population BAW male antenna showed significant loss of sensitivity to the minor pheromone component in the colony reared males. The knowledge gained from these studies will serve as a foundation for future research aimed at developing more effective integrated pest management strategies utilizing the pheromone communication channel for M. configurata.
Description
Keywords
mamestra configurata, bertha armyworm, pheromone, chemical ecology, integrated pest management,
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Biology
Program
Biology