Sex-specific variations in gypsy moth fitness, immune function, and parasite resistance mediated by background defoliation of the host plant

Abstract EN

In this study, we investigated the effect of rapid/delayed changes in silver birch foliage quality induced by minor defoliation on gypsy moth fitness, immune function, and resistance of larvae against natural enemies.

Insect fitness was estimated as pupal weight, the period of larval stage, and mortality rate.

Larval immune status was detected as activity of phenoloxidase in plasma, total hemocyte count (THC) in hemolymph, and encapsulation rate of nylon implant inserted into larvae hemocoel.

We revealed that only rapid changes after tree defoliation lead to a strong tendency of suppression in the female’s fitness.

Delayed changes in foliage chemistry led to a rise of encapsulation response in females.

Larval parasitism by hymenoptera was decreased when larvae fed on leaves from previously defoliated trees.

We propose that changes in host plant quality drive the sexspecific increase of female encapsulation rate that allows larvae better resistance against the pressure of natural enemies.