Interactive effects of body size, food abundance and mating status on reproductive attributes in tortoise beetle

Abstract

In numerous studies, it has been seen that the reproductive attributes of an insect may vary according to their body size, food fluctuation in the environment and their mating status. However, studies on the interactive effects of such biotic factors on mating behaviour and reproductive attributes are lacking. Therefore, the present study was designed to investigate the interactive effects of body size variation, different food conditions and the mating status on specific reproductive attributes such as sexual maturity, time to commencement of mating (TCM), latent period (LP), mating duration (MD), fecundity and per cent egg viability of spotted tortoise beetle, Aspidomorpha miliaris (Coleoptera: Chrysomelidae). For this, small- and large-sized females were raised in different feeding conditions (limited and unlimited food) from emergence to sexual maturity and then allowed to mate once, twice, or multiple times with males of intermediate size. Results revealed a significant influence of body size on sexual maturity, as well as mating status on the time to commence mating and showed a significant interactive effect of food conditions and mating status on latent period and mating duration, as well as body size, food conditions, and mating status on fecundity and per cent egg viability of adult females. In the present study, small females attained sexual maturity earlier than large females. Fecundity and per cent egg viability were recorded at maximum in multiply mated large females in the unlimited food treatment. Food conditions substantially influenced fecundity, which was zero in females with limited food conditions. Therefore, this study suggests that multiply mated larger females with unlimited food have better reproductive outputs. It was also concluded that the interactive effect of biotic factors had a significant impact on reproductive outputs together with different sexual behaviours.