LE3 .A278 2010

2010

Hillier, Kirk

Acadia University

Bachelor of Science

Honours

Biology

Biology

Helicoverpa zea Hübner ( Lepidoptera: Noctuidae) is a billion dollar crop pest, affecting agriculture in North and South America as well as Europe. Males have odour- secreting hairpencil glands found at the tip of their abdomen which are extruded during courtship. Previous studies have shown that hairpencil odours in similar species act as a female attractant or cause females to become quiescent, consequently making copulation attempts by males more likely to be accepted. This study was designed to determine the effects of the H. zea male hairpencil odour on the courtship behaviour of female H. zea through a series of mating assays. Normal mating assays were conducted to first determine stereotypical courtship behaviour within the moth species. Subsequent manipulations ( hairpencil ablation, antennectomy and hairpencil ablation with odour reintroduction) were performed on the moths to determine the importance of hairpencil odour in mating. Surgical control trials were performed with moths that had undergone „ mock‟ surgeries and hexane control trials were used with odour reintroduction trials. Normal assays determined stereotypical mating behaviours in H. zea. Stereotypical behaviours for males included hairpencil extension, abdominal curl, antennal tap, dragging, missing and successful clasping. For females, behaviours included flying or moving away, ovipositor extension, abdominal extension and dragging. Manipulation assays determined the presence of hairpencil pheromone plays an important role in female quiescence and consequently, copulation success rate. When able to detect hairpencil pheromone, females were less likely to move or fly away from clasp attempts. Odour reintroduction trials were unsuccessful in increasing the frequency of successful clasps of ablated males; reasons for this are unknown and require further study.

The author retains copyright in this thesis. Any substantial copying or any other actions that exceed fair dealing or other exceptions in the Copyright Act require the permission of the author.

https://scholar.acadiau.ca/islandora/object/theses:700