Olfactory learning and memory in Grapholita molesta

This study aimed to evaluate the effect of previous exposure to the essential oil of lemongrass [Cymbopogon citratus (DC) Stapf (Poaceae)] on the chemotactic behavior of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) larvae and adults. All insect responses were evaluated using a Y‐tube (dual choice) olfactometer. Experience with the essential oil for 48 h after hatching did not change the chemotactic behavior of larvae; however, when they were exposed to lemongrass for 10–12 consecutive days, they did not present a preference for either treatment. Adults originating from larvae exposed to the essential oil odor until the formation of pupae responded more to this treatment in comparison to acetone. Similar results were obtained with insects exposed for only 24 h (at the end of the last instar) to the same treatment. Similar to inexperienced individuals, adults exposed for 48 h after emergence to acetone were significantly more responsive to this compound than to the essential oil. However, insects exposed to lemongrass odor during the same period displayed no preference for either treatment. This study demonstrated that both larvae and adults of G. molesta are capable of non‐associative learning and the memory acquired in the larval stage is maintained for at least 48 h after emergence.