Can galls evolve toward a simpler morphology: a test of disruptive selection on gall morphology driven by parasitoid wasp

Gall evolution is not a one-way path. Our investigations revealed that a chestnut gall wasp employed contrasting defense strategies: simple galls use camouflage to evade detection, while complex galls sacrifice their outer layer to protect the core larvae. Both forms are equally effective against parasitoids, suggesting that gall morphology has undergone disruptive selection, rather than the commonly accepted directional selection favoring more complex galls.