Effets d'un élevage en isolement sur le développement gonadotrope, la production d'hydrocarbures cuticulaires et le comportement sexuel de Calliphora vomitoria (Diptères, Calliphoridae)

Isolated rearing (during the first gonadotropic cycle) was found to modify physiological variables (gonadotropic development, cuticular hydrocarbon production) as well as behavioral modalities of the courtship of male and female Calliphora vomitoria. In males, slower development and a decrease in the volume of the testes and the annex glands were noticed; in females, there was only a reduction in the volume of the terminal follicle without modification of the rate of growth. In contrast, cuticular hydrocarbon production was more disturbed in the female than in the male. Isolated rearing of males did not change either the number or the relative proportions and concentrations of cuticular hydrocarbons. In females, isolation was accompanied by a slight increase in both the relative proportions of cuticular hydrocarbons, namely monomethyalkanes, dimethylalkanes, and alkenes, and the concentrations of all hydrocarbons. Finally, isolated rearing was found to modify the sexual behavior of both partners. Isolated males showed later and scarcer sexual behavior than grouped males. They courted females later and more briefly, with lower frequencies and shorter durations of each stage of courtship; therefore, courtship was reduced with many interruptions. Isolated females appeared more permissive, with lower frequencies and durations of the stages of courtship, and shorter courtship. These differences were emphasized when both partners were reared in isolation. The lack of exchanges during imaginal development led, owing to lack of exercise and (or) nervous maturation, to sex-specific alterations: decreased gonadotropic development in males, modified cuticular hydrocarbon production in females, and reduced sexual behavior in both sexes.