Authors: Megan A Murphy Johannes Schul
Publish Date: 2016/12/13
Volume: 71, Issue: 1, Pages: 22-
Abstract
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 interindividual 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 fitnessFemales often show strong preferences for costly male signals that advertise male quality The preference for males producing signals ahead of their neighbors’ is unusual in that there are not necessarily any energetic costs associated with producing the preferred signals However males do compete to produce leading signals allowing for the possibility that only high quality males can “win” these interactions as some costs become associated with winning We tested whether the ability to produce leading calls advertises male quality in Neoconocephalus katydids even in the absence of energetic costs We found no correlation between the ability to produce leading calls and male quality in any species tested Though further tests are necessary this suggests that the ability to produce leading calls does not advertise male quality even when males are competing for the leading roleThis research was supported by a grant of the National Science Foundation IOS 1146878 to JS and a Graduate Assistance in Areas of National Need fellowship for MAM We would like to thank the members of our lab for their support in collection and care of specimens and their comments on this manuscript We would also like to thank the editors two anonymous reviewers Manuel Leal and Rex Cocroft for their thoughtful comments and advice
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