Thermal Ecology of Leptuca spp.: Preferences, Thermal Windows, and Thermoregulatory Capacity

• Grant number: 24/17379-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2024
• End date: October 31, 2025
• Field of knowledge: Biological Sciences - Zoology - Physiology of Recent Groups
• Principal Investigator: Tânia Marcia Costa
• Grantee: Ana Carolina Francelino
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Climate change has caused abrupt shifts in environmental conditions, increasing uncertainty about how organisms will adapt to this new climate scenario. The global average temperature has already increased by about 1.2°C since 1850. This increase may lead to a loss of homeostasis in animals due to increased energy expenditure, affecting their physiology, behavior, and ecology. Understanding the thermal biology of ectotherms can help predict how they will respond to this warming. Fiddler crabs are considered to be good indicators of climate change because climate effects influence their latitudinal distribution, intertidal occupancy, and morphological variation. Therefore, this study aims to analyze and compare the thermal ecology of three fiddler crab species. The target species are adult males of Leptuca cumulanta, L. leptodactyla and L. uruguayensis, which are similar in size and have different distributions within the mesolittoral zone. We hypothesize that there are differences in the thermal ecology of these organisms that correspond to this intertidal zonation and may be influenced by climate change. To test this, we will assess thermal preference, thermal tolerance and thermoregulatory capacity in each species. Thermal preference will be assessed by observing the animals' choices in a temperature gradient. Thermal tolerance will be measured by CTmax and CTmin values for each organism. Finally, thermoregulatory capacity will be assessed by examining heat exchange between the body and the hypertrophied claw of males. We expect that the thermal ecology of these species will shed light on whether their differential distribution is related to microhabitat temperature.