Competition decreases with relatedness and lek size in mole crickets: A role for kin selection?

Abstract

Twenty years ago, Kokko and Lindstrom (1996) introduced the hypothesis that kin selection may drive the evolution of leks, shifting the lek-paradigm away from a competitive framework and spurring research on the relatedness of males on leks. However, support for Kokko and Lindstrom's kin-selection hypothesis has been sparse; most studies have shown related males to occur on leks no more than expected by chance. Additionally, evidence supporting the proposed mechanism is mixed; by joining a lek, males do not always increase the female visitation rate on a per-capita basis. The prairie mole cricket Gryllotalpa major is a lekking cricket in which male relatives advertise in close proximity. We reject the Kokko-Lindstrom hypothesis for this species because G. major females do not preferentially visit larger leks. Interestingly, more females visited smaller leks, where the presence of larger, more highly related males suggest reduced levels of local competition. Although the mechanism continues to be explored, these results provide an alternative inclusive fitness scenario to consider for lekking species - the existence of kin benefits between related neighbors rather than spread across the lek as a whole.