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Title: The biochemistry and biological roles of the epicuticular lipid layer of the mosquito Aedes aegypti (Diptera: Culicidae).
Author: Horne, Gillian L.
Awarding Body: Staffordshire University
Current Institution: Staffordshire University
Date of Award: 2000
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The biochemical characterisation of the hydrocarbon fraction of the cuticular lipids of the vector mosquito, Aedes aegypti, was carried out using a variety of chemical methods, optimised for this application. Forty-four of the seventy-eight compounds detected by gas chromatography were identified, mainly using mass spectrometry. Several of the other compounds were partially characterised. The changes in composition of the cuticular hydrocarbon profiles in response to various biological factors such as age, gender, mating status and body part were studied using gas chromatography. Two models for age grading mosquitoes were proposed. Trends exhibited by the major hydrocarbons in response to increasing age and increased length of time in contact with the opposite sex were highlighted and body parts exhibiting gender-specific, concentrated areas of particular hydrocarbon compounds were identified. From the results, possible candidates for close range/contact pheromones and mating stimulants expressed in females were proposed. These compounds were examined for their effects on male mating behaviour using a bioassay procedure, testing both individual specimens, and paIrs of speCImens from different experimental groups ( choice tests). Monomethylhentriacontane and (to a lesser extent) monomethylnonacosane appeared to act as a mating stimulant though when present in higher localised concentrations, the males were deterred from approaching the source. It was postulated that swarming activity, resulting in a raised monomethylhentriacontane concentration in the surrounding air, was an important factor in stimulating males to mate. The straight chain hydrocarbons, n-heptacosane, n-pentacosane, n-tricosane and n-nonacosane were attractive to the males and may have action as close range chemical stimuli or contact pheromones. The very high localised concentration of nheptacosane on the abdomen of the female only, made this compound a likely candidate for a contact pheromone. Courtship and mating behaviour was observed using video filming and the feasibility of the theory that cuticular hydrocarbons may be active in modifying this behaviour was discussed in relation to these observations.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Physiology