ARE AGE SPECIFIC CHANGES IN PHEROMONE TITRE OF VIRGINS IMPORTANT IN THE REPRODUCTIVE SUCCESS OF TRUE ARMYWORM FEMALES?

Jeremy N. McNEIL-1 and Chance DELISLE-2
1-Department of Biology, Laval University. Sainte-Foy, Québec, Canada. G1K 7p4
2-Natural Resources Canada, CP 3800, Sainte-Foy. Québec, Canada. G1V 4C7


Pheromone titre in excised glands of virgin females of the true armyworm, Pseudaletia unipuncta, varies considerably in function of calling age: titres increase during the first three days of calling and then subsequenty declines. Given that there is considerable inter-individual variability in the age at which females become sexually mature, the changes of pheromone titre with calling age may affect the level of female-female competition for mates. However, in a field trial older females attracted as many mates as younger individuals indicating that, at least at high population densities, an age-related decrease in total pheromone synthesis does not negatively affect the ability of females to attract mates.


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