Androgen responsiveness to simulated territorial intrusions in Allobates femoralis males: Evidence supporting the challenge hypothesis in a territorial frog

Territoriality has been widely described across many animal taxa, where the acquisition and defence of a ter-ritory are critical for the fitness of an individual. Extensive evidence suggests that androgens are involved in the modulation of territorial behaviours in male vertebrates. Short-term increase of androgen following a territorial encounter appears to favour the outcome of a challenge. The Challenge Hypothesis proposed by Wingfield and colleagues outlines the existence of a positive feedback relationship between androgen and social challenges (e. g., territorial intrusions) in male vertebrates. Here we tested the challenge hypothesis in the highly territorial poison frog, Allobates femoralis, in its natural habitat by exposing males to simulated territorial intrusions in the form of acoustic playbacks. We quantified repeatedly androgen concentrations of individual males via a non-invasive water-borne sampling approach. Our results show that A. femoralis males exhibited a positive behav-ioural and androgenic response after being confronted to simulated territorial intrusions, providing support for the Challenge Hypothesis in a territorial frog.

Automated summary

Territoriality is crucial for the fitness of individuals, and androgens play a significant role in regulating this behavior. This study validates the Challenge Hypothesis in the highly territorial frog species Allobates femoralis, showing that males exhibit a positive behavioral and androgenic response to simulated territorial intrusions.