BEHAVIORAL CUES ASSOCIATED WITH OVIPOSITION BY TRIOZA-EUGENIAE

Trioza eugeniae oviposited significantly more eggs on Syzgium panicula tum leaves free of eggs compared to leaves with pre-existing eggs in a choice experiment, suggesting that females modify oviposition based o n cues associated with the presence of eggs. In separate experiments, females avoided ovipositing on parts of leaves where eggs were present , but readily oviposited on areas of the same leaf without eggs. Epide ictic pheromones are apparently not used by this species because femal es readily oviposited on areas of a leaf from which eggs had previousl y been removed. Females laid 57% of all their eggs along the margins o f normal leaves, but also oviposited on artificial margins produced by cutting the leaves. The preference for natural margins over artificia l margins was eliminated when the entire margin was coated with an ant itranspirant compound to mask the damaged edge. These studies show tha t ovipositing psyllids respond both to the presence of eggs and to the suitability of the substrate.