Chemical defense of Brachycephalus: evaluation of tetrodotoxin quantities, aposematism and palatability (Anura, Brachycephalidae)

• Grant number: 21/14284-7
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: April 01, 2022
• End date: May 05, 2025
• Field of knowledge: Biological Sciences - Zoology
• Principal Investigator: Taran Grant
• Grantee: João Marcos Pereira
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/15425-0 - A multi-disciplinary approach to the study of amphibian diversification: phase 2, AP.JP2

Abstract

Chemical defense is known to be an important defensive mechanism for the amphibians, nevertheless for many groups there are still gaps in the knowledge related to its diversity and variation. The use of color patterns is also part of the amphibians defense, where camouflage and aposematism are the main strategies used. Brachycephalus is a genus of anurans form the Atlantic Forest, which has some species known to present tetrodotoxin in their skin, in addition to a color variation between individuals, populations and species. For most species, information about variation in chemical defenses, its relationships with color patterns, and the role of these two strategies in the interactions with predators remain still unknown. In this project we intend to evaluate the variations of Brachycephalus chemical defenses at intra and interspecific level, quantifying the tetrodotoxin profiles. We will also carry out experiments to verify how predators recognise both strategies. The quantification data will allow us to identify the variations in chemical defense and test whether there is a correlation with the color. And from the experiments we intend to comprehend how visually oriented predators recognize Brachycephalus, through predation tests with models in situ, and how is the recognition of chemically oriented predators, using a palatability test. (AU)