Cheating for sex: inherent disadvantage or energetic constraint?

Abstract

In many species, some males gain access to females by cheating, i.e. by exploiting the reproductive investment made by other males. There are two main nonmutually exclusive hypotheses to explain the decision of an individual to switch from the classical reproductive tactic to the parasitic one: the inherent disadvantage and energetic constraint hypotheses. For the first time, we tested and compared these two hypotheses in an experimental design by manipulating food availability of males with different degrees of inherent disadvantage in the caller/satellite system of Hyla arborea. Small males were more likely to be satellites than large individuals as predicted by the inherent disadvantage hypothesis. However, food deprived males were not more likely to be satellites than those that were fed, suggesting that the energetic constraint is not the main process explaining the use of a parasitic reproductive tactic. Moreover, all else being equal, males were more likely to act as satellites if confronted with an attractive competitor than if confronted with an unattractive one. In addition, males had a greater probability of being satellites at the beginning and end of the night, whereas they were more likely to call during the middle of the night. These results could highlight synchronization between male tactics and expected female availability during the course of the night.