Influence of the habitat in the physiology of Tropidurus lizards: interaction among thermoregulation, osmoregulation, behavior and fitness

• Grant number: 24/17108-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2025
• End date: February 29, 2028
• Field of knowledge: Biological Sciences - Physiology - Compared Physiology
• Principal Investigator: Kênia Cardoso Bícego
• Grantee: Ane Guadalupe Silva
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 21/10910-0 - Physiological capacities and resilience facing climate change: exploring the functional dimension in ectothermic vertebrates, AP.TEM

Abstract

In current and future contexts of rising temperatures and prolonged droughts in some regions, reduced thermoregulatory efficiency due to reduced body water levels may result in overheating. This, in turn, may affect the performance and reproductive success of animals. However, the intensity of this effect should be different depending on the previous adaptations of organisms in their various habitats of origin. It is therefore important to assess to what extent increased ambient temperature and decreased water availability may affect different species of lizards living in different microhabitats, such as closed forests or open areas, arid or semiarid regions, and even urban environments.Thus, the present project proposes to investigate the influence of different habitats on the temperature threshold for evaporative cooling mechanisms (panting and/or gaping), under conditions of full hydration and increased salt load, and the impacts of these factors on behavioral preferences and locomotor performance. We selected Tropidurus lizard species in the Caatinga, Cerrado, Atlantic Forest, and Pantanal. For each species, measurements will be taken of pulmonary ventilation (to determine panting and/or gaping), evaporative respiratory heat loss, thermographic images of the body and head (to determine selective brain cooling), behavioral preferences when given options for cooling, water, and food access, in addition to locomotor performance, in fully hydrated individuals (control group, treated with 154 mmol/l isotonic saline solution) and with increased sodium load (treated with 2500 mmol/l hypertonic saline solution).This will allow us to assess the primary phylogenetic and/or habitat-related effects on the animals' responses to thermal and osmotic challenges. (AU)