Relationships between social behavior, morphology, and physiology in treefrogs of the Cophomantini tribe

• Grant number: 25/06933-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: October 01, 2025
• End date: January 31, 2029
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Fernando Ribeiro Gomes
• Grantee: Débora Meyer de Almeida Prado
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Amphibians exhibit a wide variety of social behaviors and can adjust their responses according to environmental challenges. However, the physiological mediators modulating this behavioral flexibility remain poorly understood, especially in non-model species. This project investigates the role of steroid hormones in regulating social behaviors in genera of the tribe Cophomantini (Aplastodiscus, Boana, and Bokermannohyla), with a focus on the species Boana faber. The research combines analyses of specimens from biological collections with field studies, evaluating relationships among aggressiveness (measured by the number of scars), relative testis size, steroid hormone concentrations (testosterone [T] and corticosterone [CORT]), immune function, and vocalization. It also examines the effects of hormonal treatments (with T and CORT) on these variables to determine causal relationships. It is expected that aggressiveness and relative testis size will be higher in males of genera with exposed nests (Boana and Bokermannohyla), which are more subject to sperm competition, and that these traits will be positively associated with T concentrations. In B. faber, steroid hormones (T and CORT) and immune function are predicted to peak at the beginning of the breeding season, and to be associated with higher calling rates. Hormonal treatments are also expected to stimulate calling behavior, aggressiveness, and immune function in B. faber males. This study will clarify whether steroid hormones act as mediators of the studied social behaviors, their interactions with testis size and immunity, and the role of nest type in Cophomantini frogs. The findings will contribute to our understanding of behavioral endocrinology and ecoimmunology in anurans.