Relevance of prolonged first mating in reproductive bioactivities of Dysdercus koenigii (Fabricius, 1775) (Heteroptera: Pyrrhocoridae)

Abstract

Abstract Adults of Dysdercus koenigii remain in continuous copula for up to 72h. The adaptive significance of prolonged copulation in the reproductive bioactivities of D. koenigii was investigated by a series of interrupted mating experiments. The adults were allowed to mate for a specified duration, after which mating was forcibly terminated. The study indicated that insemination in the female takes place during the first day of mating. This was reflected by the observation that 24h mated females laid fertile eggs. Prolonged mating modifies the female’s reproductive behaviour. The duration of mating had a profound effect on the onset of oviposition as well as the total number of eggs and egg batches laid by a female during her lifetime. Female fertility was also correlated with the duration of mating. Therefore, a female mated for 24h laid fewer fertile eggs in comparison to females mated for 48h or 72h. Hatching success decreased significantly in the egg batches laid by a female during the latter part of her life. A mated female exhibited rhythmic ovipositional behaviour. Our results indicated that the rhythmicity of the oviposition changed as a consequence of the different duration of mating. For instance, in females mated for 24h, there was a change in the number of eggs laid and in the rhythmicity of ovipositional peaks. Further, the rate of oocyte growth appeared to be enhanced by mating. This was evidenced by the shorter inter-oviposition period in the case of females mated for a longer period. It is suggested that throughout mating, females acquire additional sperm and non-gametic resources, such as male accessory gland secretions, which govern their reproductive behaviour and physiology.