SOCIALLY FACILITATED EGGLAYING BEHAVIOR IN MEDITERRANEAN FRUIT-FLIES

We examined the behavior of individual mature female Mediterranean fru it flies (medflies), Ceratitis capitata (Wiedemann), transferred from a holding cage without fruit to a clean host kumquat fruit already occ upied by another medfly female engaged in ovipositional behavior. A si gnificantly greater proportion of transferred (= test) ovipositionally naive females initiated ovipositor boring into a fruit in the presenc e than in the absence of an occupying medfly. Moreover, test females c ommenced boring significantly sooner in the presence than in the absen ce of another medfly. Interestingly, similar results occurred when a t est medfly was transferred to a kumquat occupied by an ovipositing fem ale oriental fruit fly, Bactrocera dorsalis Hendel. In contrast, there was no enhancement of propensity to bore when a test medfly was trans ferred to a kumquat occupied by a female Biosteres arisanus (Sonan), a parasitoid attacking medfly eggs. The principal proximate stimulus gi ving rise to the higher tendency to oviposit of a test medfly in the p resence of an occupying medfly or oriental fruit fly appeared to be wi ng-waving by the occupant during an encounter. We consider our finding s to be good evidence of socially facilitated ovipositional behavior i n ovipositionally naive medflies, and suggest that such females may be nefit from acquisition of a cue demonstrating the acceptability of a h ost for oviposition.