Relationship between plasma levels of corticosterone and testosterone on vocal and territorial behavior, on the Smith Frog (Hypsiboas faber).

Author(s)

Vania Regina de Assis

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2010-12-15

Examining board members

Fernando Ribeiro Gomes; Ana Maria de Lauro Castrucci; Silvia Mitiko Nishida

• Advisor: Carlos Arturo Navas Iannini

Abstract

From studies on the endocrine control of reproductive behavior in anurans, we know that many aspects of vocal behavior and agonistic interactions of these animals are related to changes in plasma levels of testosterone and corticosterone. Among the species of neotropical frogs of great interest for studies on the endocrine control of reproductive behavior stands out Hypsiboas faber, a hylid characterized by the presence of territorial males, whose agonistic interactions cover a variety of vocal patterns with aggressiveness scale, which may culminate in physical conflict. Males of H. faber also build nests for oviposition and presents optional guard of the nests with eggs. The aim of this study was to understand the interrelationships between plasma levels of corticosterone and testosterone with calling behavior and territorial defense in males of H. faber during reproductive season. These relationships were investigated by focal observations during the vocal activities, followed by blood sampling for hormonal assay. We additionally used an experimental approach, which consisted of using recorded advertisement calls (playback), simulating an invasion of another male in the territory of the focal subjects, followed by behavioral observation and blood sampling for hormonal assay. The experimental stimulus had no effect on plasma levels of corticosterone and testosterone, neither on the majority of behavioral variables. We can identify a pattern of seasonal variation in levels of corticosterone and testosterone, as well as a positive correlation between these hormones. Additionally, individuals who vocalize at higher rates have higher levels of corticosterone during the beginning of reproductive season, while higher levels of testosterone appear in individuals more responsive to stimuli from the social environment. (AU)

• FAPESP's process: 07/05972-0 - RELATION BETWEEN PLASMATIC LEVELS OF THE HORMONES CORTICOSTERONE AND TESTOSTERONE IN THE TERRITORIAL, VOCAL BEHAVIOR AND CONSTRUCTION OF NEST IN THE FROG HAMMER (Hypsiboas faber).
• Grantee: Vania Regina de Assis
• Support Opportunities: Scholarships in Brazil - Master