Sexually antagonistic coevolution of the male nuptial gift and female feeding behaviour in decorated crickets

<p>The evolution of nuptial gifts has traditionally been considered a harmonious affair, providing benefits to both mating partners. There is growing evidence, however, that receiving a nuptial gift can be actively detrimental to the female.<strong> </strong>In decorated crickets (<em>Gryllodes sigillatus</em>), males produce a gelatinous spermatophylax that enhances sperm transfer but provides little nutritional benefit and hinders female post-copulatory mate choice. Here, we examine the sexually antagonistic coevolution of the spermatophylax and the female feeding response to this gift in <em>G. sigillatus</em> maintained in experimental populations with either a male-biased or female-biased adult sex ratio. After 25 generations, males evolving in male-biased populations produced heavier spermatophylaxes with a more manipulative combination of free amino acids than those evolving in female-biased populations. Moreover, when the spermatophylax originated from the same selection regime, females evolving in male-biased populations always had shorter feeding durations than those evolving in female-biased populations indicating the evolution of greater resistance.<strong> </strong>Across populations, female feeding duration increased with the mass and manipulative combination of free amino acids in the spermatophylax suggesting sexually antagonistic coevolution.<strong> </strong>Collectively, our work demonstrates a key role for interlocus sexual conflict and sexually antagonistic coevolution in the mating system of<em> G. sigillatus</em>.</p><p>Data is presented in Microsoft Excel.</p>