Stuhl et al.: Responses of Braconids to Sympatric and Exotic-Fruit Volatiles 1031 RESponSES oF MultiplE SpEciES oF tEphRitid (diptERa) FRuit Fly paRaSitoidS (hyMEnoptERa: BRaconidaE: opiinaE) to SyMpatRic and Exotic FRuit VolatilES

opiine braconid parasitoids of tephritid pests have augmentative biological control potential, but there are no synthetic attractants to monitor their survival and dispersal following release. adults feed on fruit juices and these could be sources of attractive compounds. While orange juice (Citrus sinensis l.) is nutritious, guava juice (Psidium guajava l.) is toxic. the behavioral responses to the two juices and the juices’ volatiles were examined in two species ancestrally sympatric with guava (Doryctobracon areolatus [Szepligeti] and Utetes anastrephae [Viereck]) and a species exotic to guava’s neotropical region of origin (Diachasmimorpha longicaudata [ashmead]). it was predicted that males of the sympatric species, with an evolutionary opportunity to recognize and avoid guava, would neither feed on nor respond to guava volatiles. Females of the sympatric species were predicted to avoid feeding upon guava while responding to volatiles in the context of searching for oviposition sites. Males and females of the exotic species were predicted to feed upon and respond to both guava and orange. orange was universally fed upon and its volatiles were found to be attractive. none of the males, including the exotic species’, occupied guava feeding-stations in no-choice situations, but male U. anastrephae responded to guava volatiles. against expectations, female D. areolatus occupied guava feeding stations. in general, responses to orange were stronger and more universal than those to guava. the preference differences the various species showed between guava and orange are a step forward in identifying the chemical basis of fruit-attractiveness. they provide 1) further evidence that not all uninfested fruit are equally attractive and 2) a relatively attractive and easily obtainable standard, orange, with which to compare the attractiveness of other fruit in the future.