LE3 .A278 2010

2010

Hillier, Kirk

Acadia University

Bachelor of Science

Honours

Biology

Biology

The brown spruce longhorn beetle ( BSLB), Tetropium fuscum ( Fabr.), is an invasive species introduced to Canada from Europe. The first specimens were collected from Point Pleasant Park in Halifax, Nova Scotia in 1990, but were originally misidentified as a native species. It was not until nine years later, in 1999, that the beetle was confirmed and correctly identified in the park. In its native habitat, the BSLB usually infests dead and dying trees, whereas in its new environment in Nova Scotia it has begun infesting apparently healthy trees, primarily red spruce. A multi- agency governmental task force was set up to combat the spread of the BSLB in Halifax. Research to date has focused on the development of pheromone- based monitoring and mating disruption, though an increased understanding of this species’ sensory physiology and morphology is required. The purpose of this survey was to gather information about the distribution of three different types of antennal sensilla and investigate whether there was sexual dimorphism in terms of those distributions. Sensilla are hair- like sensory organs that project from the cuticle on many different parts of an insect’s body. Three types were examined: mechanoreceptors, olfactory receptors, and contact chemoreceptors. Antennae were examined using a scanning electron microscope and micrographs were taken from different angles to ensure a 360- degree view. The images were then examined using image- processing software. Results did not indicate any significant sexual dimorphism in terms of distribution of any of the three sensillar types examined, although a significant correlation was found between the size of an antennal segment and the density of sensilla present. This was purely a morphologically based survey, although preliminary transmission electron microscopy has been performed for future study.

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https://scholar.acadiau.ca/islandora/object/theses:755