Mating status of coexisting conspecific individuals modulate reproduction in a ladybird, Menochilus sexmaculatus

Abstract

The mating status of organisms plays a crucial role in deciphering mating decision and reproductive success of any organisms. Odour or pheromones are known to be perceived by animals through olfaction to locate mates at a distance. In this study, an attempt was made to investigate the effect of the presence of unmated and mated conspecific adults on mating and reproductive parameters of the ladybird beetle, Menochilus sexmaculatus (Fabricius, 1781). To conduct this experiment, an arena was made with the help of two Petri dishes and in such a manner that the experimental adults were only able to perceive the presence of conspecific adults of different mating status in their close vicinity. The results of the study demonstrated an early onset of mating in the presence of males compared to females. Another male in the vicinity poses competition that may force the males to establish genital contact faster. In the absence of any potential rival, copulation duration was highest. Females laid more eggs in the presence of mated females. This may be to increase offspring fitness in the presence of potential competitors for the already mated female. Females laid fewer eggs in the presence of unmated females. Unmated females nearby can be another choice for a male and thus, the male possibly limits the size of the ejaculate containing oviposition stimulants. The current study advocates that mating and reproductive behaviour are modulated according to the perceived surroundings in the form of conspecific adults of different mating status.