Lek size and female visitation in two species of tephritid fruit flies

Abstract

The notion that females prefer to visit and mate with grouped over solitary males is an oft-advanced hypothesis for the evolution of lek behaviour. A corollary of this hypothesis is that per capita mating success of males increases with increasing lek size. Few field studies have tested this prediction via experimental manipulation of lek size. Here, I describe field studies that monitored female visits to artificially created leks of varying size in two species of tephritid fruit flies, the Mediterranean fruit fly, Ceratitis capitata, and the Oriental fruit fly, Bactrocera dorsalis. No support for the female preference hypothesis was detected for B.dorsalis. However, in C.capitata, mean ratios of female sightings:signalling males were significantly greater for leks containing 18 or 36 males than leks that contained only six males. The observation that C.capitata males in natural populations typically form small leks suggests that a female–male conflict exists regarding optimal lek size.