Field-based body temperatures reveal behavioral thermoregulation strategies of the Atlantic marsh fiddler crab Minuca pugnax
Date
2020-07-04
Journal Title
Journal ISSN
Volume Title
Publisher
biorxiv.org
Abstract
Behavioral thermoregulation is an important defense against the negative impacts of
climate change for ectotherms. In this study we examined the use of burrows by a
common intertidal crab, Minuca pugnax, to control body temperature. To understand
how body temperatures respond to changes in the surface temperature and explore how
efficiently crabs exploit the cooling potential of burrows to thermoregulate, we measured
body, surface, and burrow temperature data during low tide on Sapelo Island, GA in
March, May, August, and September of 2019 . We found that an increase in 1°C in the
surface temperature led to a 0.70-0.71°C increase in body temperature for females and
an increase in 0.75-0.77 °C in body temperature for males. Body temperatures of small
females were 0.3°C warmer than large females for the same surface temperature. Female
crabs used burrows more efficiently for thermoregulation compared to the males.
Specifically, an increase of 1 degree C in the cooling capacity (the difference between the
burrow temperature and the surface temperature) led to an increase of 0.42-0.50°C for
females and 0.34-0.35 °C for males in the thermoregulation capacity (the difference
between body temperature and surface temperature). The body temperature that crabs
began to use burrows to thermoregulate was estimated to be around 24 degree C, which is far
below the critical body temperatures that could lead to death. Many crabs experience
body temperatures of 24 °C early in the reproductive season, several months before the
hottest days of the year. Because the use of burrows involves fitness trade-offs, these
results suggest that warming temperatures could begin to impact crabs far earlier in the
year than expected.
Description
Manuscript preprint and associated data files
Keywords
thermoregulation, thermal ecology, marine invertebrates, Minuca pugnax