Sequestration efficiency and alkaloid composition in poison frogs of the family Dendrobatidae

Author(s)

Adriana Moriguchi Jeckel

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2020-11-13

Examining board members

Taran Grant; Andrés Eduardo Brunetti; Celia Regina Ribeiro da Silva Carlini; Alan Howard Savitzky

• Advisor: Taran Grant; Ralph Anthony Saporito

Abstract

Several species of animals independently evolved the ability to sequester compounds from their diet. In this mechanism, compounds are ingested, absorbed, transported and stored in specialized tissues. These species have developed mechanisms and strategies to eat and accumulate high quantities of these chemical compounds avoiding self-intoxication. Poison frogs are the most widely studied group of vertebrates that sequesters defense compounds from dietary sources. They primarily sequester alkaloids from ants and mites and accumulate them in skin poison glands. Due to the origin of defense compounds, an important characteristic of this system is the high inter- and intraspecific variation of types, quantity and composition of alkaloids. Ecological factors such as geographic location, season, sex, age and life stage and body size are known to directly interfere in the composition and amount of alkaloids present in each individual and population. However, little is known about the mechanism of sequestration itself and how it can also be responsible for the variation of alkaloids in poison frogs. The general objective of this doctoral thesis was to evaluate how the sequestration mechanism affects the variation of types, quantity and general composition of alkaloids found in poison frogs of the family Dendrobatidae. The chapters follow a manuscript format to be submitted to their respective journals. In general, the hypotheses tested provided more information about this area of study, demonstrating that (1) there is wide variation in sequestration efficiency per species, alkaloid type, alkaloid concentration, and alkaloid modification; (2) sequestration in poison frogs is an inefficient process; and (3) there seems to be a plesiomorphic mechanism of detoxification/degradation of alkaloids in anurans that prevents intoxication. Those results support that this mechanism is even more complex and multifactorial than originally hypothesized, as well as point to important directions for future research. (AU)

• FAPESP's process: 16/09999-9 - Sequestration efficiency, metabolism and excretion of alkaloids in poison frogs and their non-sequestering relatives
• Grantee: Adriana Moriguchi Jeckel
• Support Opportunities: Scholarships in Brazil - Doctorate