Thermal tolerance and climate warming sensitivity in tropical snails

Area of Science:

• Marine Biology
• Climate Change Ecology
• Ecotoxicology

Background:

• Tropical ectotherms are predicted to be vulnerable to climate change due to narrow thermal tolerance.
• This prediction is largely based on insects and lizards, with limited data on other taxa.
• Intertidal ectotherms face extreme temperature fluctuations, potentially influencing their thermal tolerance.

Purpose of the Study:

• To investigate the heat tolerance of tropical eulittoral snails (Littorinidae and Neritidae).
• To assess the vulnerability of these snails to climate warming across different habitats and geographic locations.
• To evaluate the role of habitat and behavior in thermal safety margins.

Main Methods:

• Measured heat coma temperatures (HCT) and upper lethal temperatures (ULT) for 40 tropical snail species.
• Estimated extreme body temperatures using a heat budget model with historical climate data.
• Analyzed phylogenetic variation in thermal tolerance and calculated Thermal Safety Margins (TSM).

Main Results:

• Snail HCT averaged 44.5°C and ULT averaged 52.1°C, showing limited adaptive variation across species and locations.
• Snails from sunny rocky shores had negative TSMs, indicating body temperatures near or exceeding tolerance limits.
• Snails from shaded mangrove habitats had positive TSMs, suggesting greater thermal safety.

Conclusions:

• Habitat type (rocky shore vs. mangrove) and associated thermal regimes significantly influence snail vulnerability to climate warming.
• Behavioral thermoregulation likely mitigates risks for snails in exposed, high-temperature environments.
• Generalizations about climate change impacts on ectotherms should consider diverse taxa, ecological contexts, and behavioral adaptations.