Social ontogeny in the communication system of an insect

In humans and some other mammals and birds, the development of communication systems requires social feedback. How do such systems evolve from ancestral states featuring innate developmental mechanisms? We report evidence of a novel form of social ontogeny in the communication system of Enchenopa treehoppers that suggests an answer to this question. These insects use plant-borne vibrational signals throughout their lives. Signal repertoires of nymphs and adults differed and showed sexually dimorphic ontogenetic trajectories; individual differences projected into some of the features of adult signals and mate preferences. Signals and mate preferences differed between adults reared in isolation and adults reared in groups, but even individuals reared in isolation developed species-typical signals. In this type of social ontogeny, peer inputs cause variation in signals and preferences. Thus, even innate communication systems can be socially malleable. This may set the stage for the evolution of obligate social feedbacks in communication: the starting point is already socially plastic and does not require learning to arise de novo.