The behavioral responses of the egg parasitoid Ooencyrtus telenomicida to semiochemicals from first and second trophic level

In this study the responses of females of the egg parasitoid Ooencyrtus telenomicida (Vassiliev) (Hymenoptera: Encyrtidae) to volatile and contact chemicals from its host Nezara viridula (L.) (Heteroptera: Pentatomidae) and from host plant Solanum lycopersicum L. were investigated in a Y-tube olfactometer and in open arena. Our results in the Y-tube olfactometer tests showed that: (1) female wasps were attracted to volatiles from adult host virgin male and to volatiles from a host mated female, showing a clear preference for the volatiles emitted from the former; volatiles from host virgin females did not attract O. telenomicida females; (2) only volatiles produced by host-damaged plant complex were attractive to wasp females, while volatiles from undamaged, damaged or egg carrying damaged tomato plants were not. In open arena tests, O. telenomicida females did not respond to chemical traces left by N. viridula adults in the different sexes and/or physiological conditions. The behavioral implications of these results are discussed matching up to different strategies adopted by the egg parasitoid Trissolcus basalis and focusing on possible intraguild interactions between these two parasitoid species which in field can share the same N. viridula egg masses.