Auditory distractions redistribute hermit crabs’ finite attention, which in turn may interfere with important decision making skills such as food selection, mate selection, and predator detection. Thinstripe hermit crabs, Clibanarius vittatus, were studied to determine the effects that noise levels have on the crab's perception of environmental danger. We observed how long the hermit crabs stayed in their shell after an introduced threat in both a quiet room and a noisy room.
A sample size of 100 C. vittatus was collected on the shore of a saltwater marsh ecosystem in Marineland, Florida. The crabs were sorted into three size classes based upon their weight. Of these crabs, ten from each size class (30 individuals total) were randomly selected to be used in this experiment. Threats were simulated through human contact. The crabs were picked up, turned onto their backs, and tapped on the claw to encourage retraction into the shell. Audio clips of conversation were played at a high volume through a large speaker in order to replicate human noise pollution.
Results/Conclusions
For all thinstripe hermit crabs, regardless of size class and noise presence, there were no statistically significant differences in shell emergence times. Hermit crabs in both the large and small size classes had a longer emergence time in the noisy room, whereas medium sized hermit crabs had a longer emergence time in the quiet room. Large hermit crabs, weighing between 49.8 and 69.8 grams, had a time difference of 21.3 seconds between both rooms. Medium crabs, weighing between 29.8 and 49.8 grams, had a time difference of 5 seconds, and small hermit crabs, weighing between 9.8 and 29.8 grams, had the biggest difference in time between shell emergences with a difference of 25.7 seconds. As recreational activities increase along shorelines, a corresponding increase in sound production occurs. Consequently, it is important to understand how the behavior of several species, including ecologically important energy recyclers like thinstripe hermit crabs, will be affected. While results for this experiment were statistically insignificant, studying the relationship between behavior and environmental noise level is vital for the successful implementation of ecological and wildlife management tactics.