Neural and behavioral evolution in an eavesdropper with a rapidly evolving host.

The diversification of animal communication systems is driven by the interacting effects of signalers, signal receivers, and the environment. Yet, the critical role of unintended receivers, like eavesdropping enemies, has been underappreciated. Furthermore, contemporary evolution of animal signals is rare, making it difficult to directly observe this process.

Parasitoid-host eavesdropping reveals temperature coupling of preferences to communication signals without genetic coupling.

Receivers of acoustic communication signals evaluate signal features to identify conspecifics. Changes in the ambient temperature can alter these features, rendering species recognition a challenge. To maintain effective communication, temperature coupling-changes in receiver signal preferences that parallel temperature-induced changes in signal parameters-occurs among genetically coupled signallers and receivers.