Abstract:

Electroantennogram (EAG) responses of the generalist parasitoid Campoletis chlorideae Uchida to a range of plant volatiles and host pheromone gland compounds were investigated. The EAG responses were maximal for the C₅－C₇ alcohols, and declined as the carbon chain-length of compounds increased or decreased. Aliphatic aldehydes, acetones, acids and esters could also trigger significant EAG responses. All monoterpene hydrocarbons elicited low EAG response, while oxygenated monoterpenes elicited relatively high responses. Three aromatic compounds elicited significant EAG responses. Compounds that showed significant EAG responses at dose of 100 μg elicited dose-dependent EAG response, while α-pinene and (E)-caryophyllene evoked little responses at all tested dosages. All tested host pheromone gland compounds elicited significant EAG response at the dosage of 100 μg and 1 000 μg. Tested with 100 μg and 1 000 μg of host pheromones, the male parasitoids showed responses two times as high as that of the female. The role of plant volatiles in host location behavior of the parasitoid was discussed.

Key words: Campoletis chlorideae, parasitoid wasps, plant volatiles, host pheromone gland compounds, EAG response, host location