Abstract

In moths, the female generally produces the sex pheromone in a gland, formed from modified epidermal cells, located between the 8th and 9th abdominal segments. A male moth perceives the pheromone through its antennal receptors, which are tuned to the sex pheromone components produced by the female. Typically, following copulation, a female often becomes unreceptive to further mating attempts by males. Several factors have been postulated to be responsible for this, including the physical act of mating, sperm and seminal fluids. Mating is known to cause either a permanent or temporary cessation of sex pheromone production in many species of moths. The effects of female and male age on time of copulation and periodicity of H. electellum were investigated. Individual virgin females of H. electellum, age 1, 2, 3, 4 and 5 days, were placed with a single conspecific virgin male (2–4 days old) in a 20 ml glass vial 3 h prior to the onset of the scotophase, in a room under the same conditions as those of the respective colonies. The percentages of copulations, and percentages of females with spermatophore in their bursa copulatrix, were compared by χ2 analyses; if there were any significant differences, each pair was compared by a χ2 analysis. The distributions of time that copulation started for the different age females and males were compared, respectively, by chi-squared tests. Female age had a significant effect on the proportion of copulations, with a significantly smaller proportion of the youngest females (1 d) copulating than of the older females (2–5 d). High proportions of females that copulated had spermatophores in their bursa copulatrix, regardless of age; there was no significant difference in these proportions among any of the different-aged females.