Effects of temperature increase on the physiology and behavior of fiddler crabs

Author(s)

Vianna, Brunna da Silva ^[1] ; Miyai, Caio Akira ^{[1, 2]} ; Augusto, Alessandra ^{[1, 2]} ; Costa, Tania Marcia ^{[1, 2]}

Affiliation

^[1] Sao Paulo State Univ UNESP, Biosci Inst, Coastal Campus, Praca Infante Dom Henrique S-N, BR-11330900 Sao Vicente, SP - Brazil

^[2] Sao Paulo State Univ UNESP, Aquaculture Ctr CAUNESP, Via Acesso Prof Paulo Donato Castellane S-N, BR-14884900 Jaboticabal, SP - Brazil

• Document type: Journal article
• Source: Physiology & Behavior; v. 215, MAR 1 2020.
• Web of Science Citations: 0

Abstract

Intertidal organisms rely on physiological and behavioral adjustments to maintain homeostasis under warm exposure. We examined the effects of the temperature increase related to climate warming on the physiology and behavior of two fiddler crab species: Leptuca uruguayensis, which inhabits mostly vegetated areas, and Leptuca leptodactyla, that inhabits unvegetated areas. We hypothesized that L. uruguayensis would be more sensitive to warming than L leptodactyla. Crabs were exposed to different temperatures: 27 degrees C (control), 31 and 33 degrees C (+4 and +6 degrees C, respectively) for 15 days to evaluate their physiological responses (oxygen consumption, Q(10), ammonia excretion and hepatosomatic index) and for 2 days to observe their behavioral responses (feeding rate and duration of burrow retreat). We also tested in situ the effect of air, surface, and body temperatures on the claw-waving display of both species. We found that species were affected differently by increasing temperature. Leptuca uruguayensis showed adaptation limit (Q(10) < 1), increasing oxygen consumption. Also, in comparison with control, L. uruguayensis decreased the ammonia excretion at 31 degrees C, but not at 33 degrees C, indicating a compensatory mechanism to cope with thermal stress. In contrast, L. leptodactyla was able to adjust its metabolic rate to temperature rise (Q(10) similar to 3) and reduce ammonia excretion, suggesting changes in the energetic substrate and amino acid catabolism. Higher temperatures reduce the hepatosomatic index of both species, indicating increased use of energy reserve (although only the L. uruguayensis feeding rate was reduced). Furthermore, warmer temperatures increase the duration of burrow retreat in both species, potentially impacting social interactions, such as mating. Temperature increase did not affect the claw-waving display frequency, suggesting that other factors may affect this behavior, e.g., the presence of females and competitors. Specific behavioral (e.g., microhabitat selection) and morphological attributes (e.g., larger major claw) might benefit the thermoregulation of each crab species since no differences in body temperature were found between them in situ. Therefore, fiddler crabs that inhabit vegetated areas are more vulnerable to higher temperatures and may change its geographic range as a result of climate warming, while fiddler crabs that inhabit unvegetated areas are more tolerant to temperature rise and may have a competitive advantage under a temperature increase scenario. (AU)

• FAPESP's process: 14/16983-6 - Effects of ocean acidification and change of temperature and salinity on physiology of the fiddler crabs: a study in laboratory
• Grantee: Alessandra da Silva Augusto
• Support Opportunities: Research Program on Global Climate Change - Regular Grants
• FAPESP's process: 19/01741-0 - The Crustacean Society Mid-Year Meeting
• Grantee: Tânia Marcia Costa
• Support Opportunities: Research Grants - Meeting - Abroad
• FAPESP's process: 15/50300-6 - Climate change impact on São Paulo's estuarine fauna at pertinent parameter ranges and spatial scales: the effects of temperature and pH on fiddler crab larval development
• Grantee: Tânia Marcia Costa
• Support Opportunities: Research Program on Global Climate Change - Regular Grants