Mediterranean Fruit Fly (Diptera: Tephritidae) in Nature: Location and Diel Pattern of Feeding and Other Activities on Fruiting and Nonfruiting Hosts and Nonhosts

Abstract

Systematic quantitative observations of locations and diel patterns of activities of adult Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were made in a semiisolated mixed orchard and surroundings in southern Egypt during 4 wk in early autumn 1984. Flies were regularly sighted on all fruiting and nonfruiting hosts, whereas on nonhost vegetation they were observed occasionally. At dawn, both sexes were at rest in upper sunlit parts of tree canopies, where females began primarily feeding and males released pheromone and began calling activities. With increasing temperature and light, flies moved progressively to lower, more shaded positions. Most feeding events occurred on juice oozing from ripe guava and wounds on orange fruit. Bird droppings and leaf surfaces (probably providing bacteria as nitrogen sources) were additional important feeding sites. Male feeding on fruit peaked in the late afternoon; most ovipositions (on orange and guava) also occurred then. The high level of predation on fruit is proposed as an explanation of the origin of lek behavior on foliage. We, as observers, could detect leks by the odor of the male pheromone. Preferred sites for lek formation were the illuminated areas of tree canopies that were on or near fruiting host trees and that were protected by dense foliage from intense predation by Odonata and wasps. The greatest number of calling males, bouts of male-male competition, leks, and mating pairs were found on fruiting citrus trees. Attraction of females to calling males and formation of mating pairs peaked in midmorning and again following hot midday temperatures.