Olfactory cues used by a larval parasitoid of fruit flies to find its host

DIEGO F. SEGURA; MARIANA M. VISCARRET; SERGIO M. OVRUSKI; JORGE L. CLADERA

Florida, EEUU

Congreso; 5th Meeting of the Working Group on Fruit Flies of the Western Hemisphere; 2004

Laboratory tests in small cages were performed to study the factors involved in hosts searching by the larval parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae). We have shown that D. longicaudata is able to choose an infested fruit when this is simultaneously offered with a not infested fruit. The present study included products associated with the activity of the adults and larvae of its host, Ceratitis capitata (Diptera: Tephritidae) while feeding on fruits of orange, Citrus sinesis. We separately analyzed here five different factor associated with odors from an infested fruit: a) odors produced by the fruit after it was pierced by the flies; b) odors from the communication or activity of the adults flies left over on the fruit surface (flies feces, females host marking pheromone); c) odors left behind by the larvae moving inside the fruits; d) odors from the larvae themselves; and e) odors produced by other organisms associated with the infestation (e.g., fungus). So far we have been able to rule out the odors associated to the activity of the adults on the surface of the fruit, and the odors released by the fruit immediately after the flies lay their eggs. Odors that seem to be acting as a chemical cue in the host searching process of these parasitoids are associated to the activity of the larvae or are produced by fruits when reaching an advanced degree of maturation as a consequence of the attack of the flies.