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

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.

Previous exposure to other males leads to prolonged copulation by a predatory true bug (Hemiptera: Heteroptera: Anthocoridae)

Mating pairs ofAnthocoris whiteiReuter (Hemiptera: Heteroptera: Anthocoridae) irregularly exhibit copulations exceeding five hours in duration. In other Heteroptera, male-biased sex ratios or high densities of male conspecifics may lead to prolonged copulation. I tested whether exposure to conspecific males preceding access to females led to prolonged copulations byA. whitei. Copulations in which the male had been exposed to other males were significantly longer (by 60+ minutes) than copulations in which the male had not been exposed to other males. Durations exceeded five hours in several pairings following exposure to other males. Almost 75% of copulations in which males had not been exposed to other males were <100 minutes in duration, whereas only 22%–29% of copulations involving males that had been exposed to other males were <100 minutes in duration. Atypically long copulations by this species may be a form of postinsemination mate guarding to prevent insemination of a guarded female by other males.

Prolonged copulation and the internal dynamics of sperm transfer in the water strider Aquarius remigis

Copulations lasting much longer than required to effect insemination are common throughout the Insecta, but their adaptive significance remains obscure. We address the hypothesis that prolonged copulations benefit male Aquarius remigis (Hemiptera, Gerridae) by influencing sperm use and storage following insemination. We describe the gynatrial complex of females and document sperm location immediately following 32 naturally terminated and 25 artificially terminated copulations. We also examine sperm storage in 22 females isolated from males for 2–10 days. Our results demonstrate that insemination occurs at the end of copulation, and therefore that prolonged copulation is not a post-insemination mate-guarding tactic, as was previously assumed. Sperm are transferred in a coherent, coiled mass and move rapidly to the spermathecal tube, the primary storage organ. However, a few sperm move directly to the fecundation canal and hence should be capable of immediate fertilization. Prolonged copulation is associated with increased filling of the spermathecal tube, which may indicate some form of copulatory courtship or sperm loading by males during the prolonged pre-insemination phase. We discuss this new interpretation of prolonged copulation in A. remigis in the context of the overall costs and benefits of prolonged copulation for both sexes under the natural conditions of polygynandry.