16 - Lek behavior of insects

Summary

(The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick

Charles Darwin (Darwin, F. 1887, vol. 2, p. 296))

ABSTRACT

We provide a general overview of lek behavior in insects. Initially, we draw a distinction between substrate–based and aerial (swarming) male mating aggregations. In general, males in substrate–based groups defend territories, wait for arriving females, and perform courtship prior to mating. By contrast, males in swarms typically exhibit no intrasexual aggression before female arrivals and grasp approaching females for immediate mating without courtship. Also, compared with swarms, substrate–based aggregations tend to be small, and males are more likely to produce long–range signals to attract females. We examine the relative importance of intra– and intersexual selection in substrate–based groups with (1) male aggression but no courtship, (2) male courtship but no aggression, and (3) both male courtship and aggression. The final category, groups most closely resembling ‘classical’ lek species, receives most attention; data from drosophilid and tephritid fruit flies are presented to show interspecific differences in the influence of male aggression and female choice on male mating success. Few data are available that address the evolutionary origins of lek behavior in insects. Among male–initiated hypotheses, it is most likely that males cluster at transit ‘hotspots’ where large numbers of females are likely to pass. There is no empirical support for the idea that clustering increases signal effectiveness and hence female arrivals on a per male basis. In addition, data regarding predation and group size do not consistently reveal reduced risks with increasing group size.