Title: Responses of multiple species of Tephritid (Diptera) fruit fly parasitoids (Hymenoptera:Braconidae:Opiinae) to sympatric and exotic and fruit volatiles Authors
Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 4, 2012
Publication Date: December 1, 2012
Citation: Stuhl, C.J., Sivinski, J.M., Teal, P.E., Aluja, M.R. 2012. Responses of multiple species of Tephritid (Diptera) fruit fly parasitoids (Hymenoptera:Braconidae:Opiinae) to sympatric and exotic and fruit volatiles. Florida Entomologist. 95(4):1031-1039. Interpretive Summary: Tephritid fruit flies consume hundreds of fruits and vegetables and are responsible for trade restrictions wherever they occur. Augmentative biological control is one means of controlling fruit flies, but there is no synthetic attractant that can be used to monitor the survival and dispersal of natural enemies following their release. Scientists at the USDA-Agriculture Research Service, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, have investigated the responses of three species of fruit fly parasitoids to the odors produced by oranges and guavas, the first a high quality food for adult fruit fly parasitoids and the second toxic. In general, males and females of all three species flew more to sources of orange odor and stayed there longer. The next step will be to compare the chemicals that make up the smells of the two fruits and identify which are attractive in orange, and/or repellant in guava.
Technical Abstract: 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 respond 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.