Lek site selection by male Mediterranean fruit flies

The mating system of the Mediterranean fruit fly, Ceratitis capitata (Wiede mann), is based on leks. In field cage choice experiments we examined lek s ite selection as influenced by the presence of fruit and the presence of co nspecific flies, Males were allowed to choose between artificial trees cont aining fruit and trees without fruit. Males showed a significant preference for the tree baited with fruit. To determine which fruit-related stimuli w ere important males were allowed to choose between visual and/or olfactory fruit-derived stimuli. Males preferred to lek on trees presenting both stim uli. To determine the influence of conspecifics on lek site selection, male s were allowed to choose between trees containing male and/or female conspe cific flies. The presence of pheromone-emitting males was preferred. In add ition, both in the field and on artificial trees, we examined the effect of leaf size on lek site selection. In the field, males preferred to lek on l eaves of a particular size. Moreover leaf integrity was important, as males tended to select undamaged leaves as lek sites. In field cage experiments, males consistently chose to lek on trees containing the largest leaves. We conclude that the choice of lek site is influenced by the presence of frui t and of other lekking males, while leaf size and integrity determine male location within a lek.