Does leadership indicate male quality in Neoconocephalus katydids?

摘要

Females of many species show strong directional preferences for costly male signals, which serve as indicators of male quality. Leader preference, a directional preference for males producing their signals ahead of their neighbors', is unusual in that there are no inherent costs to producing the attractive signal. Nonetheless, interacting males compete to produce leading signals, with the winner gaining a large fitness advantage. Here, we test whether competition to produce leading calls is sufficient to make leadership an honest indicator of male quality in the absence of costs in Neoconocephalus katydids. We include one species with leader preference and two without to determine whether any correlations between signal and quality arose before or after the evolution of leader preference. We found no correlations between leadership and male quality in any species tested, suggesting that the production of leading calls does not serve as an honest indicator of quality. This is likely the ancestral state for this system. The ability to produce leading calls in N. ensiger, the species with leader preference, was not correlated with costly call traits. However, the ability to produce leading calls was highly repeatable, allowing for the possibility that it encodes meaningful information about males. The inter-individual variation in the ability to produce leading calls is likely caused by neural properties within the central pattern generator; this variation is likely due to both genetic and environmental factors. Though we found no evidence that females gain a fitness benefit by mating with leading males, we cannot exclude the possibility without tests of female fitness.