Serial effects of host infestation on egg allocation by the Mediterranean fruit fly: a rule of thumb and its functional significance

Prior infestation of host kumquats Fortunella japonica with the eggs of Ceratitis capitata had a number of effects on the oviposition behaviour of conspecific flies. Overall, infestation markedly reduced the rate at which clutches were laid by a female searching within a host tree. Egg infestation decreased the probability that a female 1) bored with her ovipositor after landing on a fruit and 2) deposited a clutch once oviposition-boring was initiated, and 3) deposited additional clutches at new sites on the fruit before leaving. Egg infestation also decreased duration of an oviposition (and thus probably clutch size) and tended to decrease the persistence with which a female foraged on fruit. Infestation had no effect on the persistence with which a female foraged within a tree or on the rate at which a female landed on fruit. A simple rule of thumb for response by Mediterranean fruit flies to egg infestation is presented. This rule implies that different foraging traits such as clutch size and giving up time are mechanistically related and should not be treated independently in foraging theory. Both survival to pupation and the expected fecundity of survivors decreased progressively as egg density in host fruit was artificially increased, suggesting that progeny deposited in egg-infested fruit have lower fitness than progeny deposited in uninfested fruit. -from Authors