Secondary contact between closely related species can lead to hybridization. The fitness of hybrid individuals within and outside the hybrid zone determines whether the hybrid zone expands into the ranges of the 2 parental species or remains a stable, geographically narrow area in between the...

Birdsong is a sexually selected and culturally transmitted multidimensional signal. Sexually selected traits are generally assumed to indicate condition. In oscine songbirds, song is learned early in life. The developmental stress hypothesis proposed that poor early developmental condition can...

Prominent research areas such as animal communication and sexual selection use birdsong as a model system. Most studies on these subjects are conducted on species with typical sex roles with male-biased song production. Accordingly, the functions of birdsong, mate attraction, and territorial...

Sound production in fish is widespread and occurs in several contexts, such as species recognition, mate choice, and aggression. However, there is little experimental evidence for the importance of acoustic signals in social contexts and the influence of sound on mating decisions of females....