Crepuscular vocal partitioning and thermal limits on calling behavior in the Bubbling Kassina (Kassina senegalensis) in a sub-equatorial savanna.

Acoustic communication in anurans is energetically costly and constrained by environmental factors, especially in open savanna ecosystems where extreme temperature fluctuations, desiccation risks, and wind-induced noise pose significant challenges to signal propagation and caller physiology. We analyzed the acoustic ecology of the widespread bubbling Kassina (Kassina senegalensis) in Mozambique, and compared it with that of other locations. We examined the influence of temperature, photoperiod and moonlight on calling phenology. Calling phenology was strongly seasonal driven, while daily patterns showed a bimodal strategy with peaks at dawn and dusk. This crepuscular activity suggests a behavioral adaptation to optimize signal transmission during stable atmospheric conditions and/or reducing desiccation. We identified a thermal window for vocalization (~ 23-27 °C), with activity sharply declining above 30 °C, suggesting a physiological upper limit. Moonlight also had an effect on calling activity. These findings highlight the behavioral and physiological plasticity of K. senegalensis in navigating savanna constraints, offering insights into ectotherm neuroethological adaptations amid climate change.