Multifunctional behaviour in a sandy shore crab enhances performance in extreme intertidal environments

Area of Science:

• Marine Biology
• Behavioral Ecology
• Animal Physiology

Background:

• Tropical soft-sediment shores are dynamic environments with extreme temperatures that challenge organismal survival.
• Behavioral adaptations are critical for intertidal species to cope with fluctuating environmental conditions and thermal stress.

Purpose of the Study:

• To investigate the thermoregulatory function of sponging behavior in the deposit-feeding crab, Scopimera intermedia.
• To determine the role of sponging in the thermal performance and survival of crabs in tropical intertidal zones.

Main Methods:

• Quantified thermal physiology of Scopimera intermedia through thermal performance curves.
• Recorded environmental temperatures during crab activity periods on tropical sandy shores.
• Simulated field body temperatures to assess the impact of sponging on thermal performance using experimental data.

Main Results:

• Sponging behavior was positively correlated with feeding rate, replenishing water for flotation feeding.
• Sponging reduced crab body temperatures by an average of 1.3°C.
• Simulated crabs unable to sponge exceeded their critical thermal maximum nearly 2000 times more often than sponging crabs.

Conclusions:

• Sponging is a multifunctional behavioral trait vital for both feeding and thermoregulation in Scopimera intermedia.
• Multifunctional traits are likely widespread but overlooked adaptations in intertidal species facing extreme environmental fluctuations.
• Maintaining functional body temperature is energetically costly, highlighting the importance of behavioral adaptations in harsh intertidal habitats.