The kin selection hypothesis in a lekking mole cricket: assessing nested patterns of relatedness

Loosely defined, a lek is a male mating aggregation visited by females primarily for the purpose of fertilization. No consensus has been forged that successfully explains how and why leks have evolved across the full breadth of lekking taxa. The two major conceptual explanations (cooperation and competition) are both intricately intertwined in any given system and exhibit varying levels of plasticity based on an organism's environment and life history. The kin selection hypothesis suggests that if females prefer larger leks (as is often the case), unattractive males may aggregate with their attractive relatives in order to boost the latter's reproductive success, while effectively sacrificing any opportunities of their own. Here we develop microsatellite markers to genetically evaluate the kin selection hypothesis by measuring relatedness and precise spatial locations of males in a population of the lekking prairie mole cricket (Gryllotalpa major Saussure). Results indicate that neighbouring males are often highly related, suggesting that kin selection may play some role in this system. However, because leks are comprised of multiple kin groups, if kin selection is operating it is likely doing so at a smaller scale than predicted by the kin selection hypothesis of lek formation. The high levels of subgroup relatedness within this species likely occurs as a passive process due to male viscosity, but the functional implications of this interesting genetic organization remain unknown.