Condition dependent signalling and mating behaviour in the tree cricket Oecanthus henryi

Abstract

Male reproductive success in systems exhibiting sexually selected traits can be driven by male mating effort in sexual signals and in the production of nuptial gifts. Male mating effort can be determined by various biotic and abiotic factors, such as nutritional quality, age, body size, mating status and temperature, contributing to the immediate condition of the male. Less preferred males in certain systems can also evolve condition-dependent alternate tactics to improve their reproductive fitness. In systems that involve long-distance acoustic signaling by males for mate attraction, in addition to male mating effort, female motivation to acoustically localize a potential mate can also impact male reproductive success. Female motivation can again be governed by female condition, depending upon nutritional status, age, size and mating status. Crickets of the order Orthoptera are excellent model systems to study all of the above. Males typically engage in energy-demanding long-distance acoustic signalling to attract conspecific females. Intraspecific variation in male investment in signalling and signal quality can be a key factor in determining the attractiveness of males to conspecific females and hence their reproductive fitness. Male mating effort in signalling can show condition-dependent trade-offs with other life history traits such as lifespan. Moreover, several orthopteran species also produce nuptial gifts that females feed on during mating. As most orthopterans are also polygamous, the replenishment time of nuptial meal and spermatophore can constrain the number of mating opportunities procured by males, thereby influencing their fitness. Male investment in number of matings and quality of nuptial gift can show condition-dependent variation. Although condition-dependent male investment in nuptial gifts and multiple matings has been the focus of many sexual selection studies, to the best of our knowledge, how various aspects of mating (re-mating propensity, latency to re-mate, investment in nuptial...