Associative learning and memory duration of Trichogramma brassicae

Learning ability and memory duration are two inseparable factors which can increase theefficiency of a living organism during its lifetime. Trichgramma brassice Bezdenko (Hym.:Trichogrammatidae) is a biological control agent widely used against different pest species.This research was conducted to study the olfactory associative learning ability and memoryduration of T. brassicae under laboratory conditions. According to our results, T. brassicaeshowed olfactory learning ability in response to conditioned odors, and this learned olfactorystimuli lasted for 20 hours. In a second experiment, the effects of frequent experiences on thememory duration of females were studied. A direct relationship between frequent experiencesand memory duration was observed. When exposed to a conditioned odor, wasps’ memoryduration increased in response to the number of experiences. Memory was observed at 28 hafter one extra conditioning. The duration of the associative memory lasted 42 hours when 2extra experiences were given, 50 hours after 3 experiences, and 58 hours after 4 extraconditioning experiences. Our results showed that T. brassicae can associate new odors to hostexistence, and they will show increased memory duration after multiple experiences.