TESTS OF HYPOTHESES FOR LEK FORMATION IN A HAWAIIAN DROSOPHILA

Several hypotheses for the formation of leks were tested in laboratory experiments using a Hawaiian fruit fly, Drosophila grimshawi. Males formed leks spontaneously when placed into large enclosures, making it possible to test hypotheses for lek formation that are difficult to test in the field. The signalling, lek choice, hotspot, and search-cost hypotheses were addressed. Results indicated that several selection pressures may be responsible for the evolution of leks in D. grimshawi. The 'hotspot' hypothesis was strongly supported, but reduced search cost and 'hotshot' mechanisms may also apply. No evidence was found to support the lek-choice or signalling hypotheses. Results from mating experiments indicated that D. grimshawi females probably discriminate among potential mates once at a lek, but female choice was concluded to be too weak to be a significant force for male aggregation. © 1994 The Association for the Study of Animal Behaviour.