Group size and individual ‘personality’ influence emergence times in hermit crabs

Broadhurst, Harvey Eliot; Morrell, Lesley J

Abstract

Many animals benefit from aggregating due to the anti-predator effects associated with living in groups. Hermit crabs are known to form groups, or ‘clusters’, which may occur at sites of high shell availability. Clustering may also have anti-predator benefits, if individuals in larger clusters able to spend less time engaging in defensive behaviours such as hiding in their shells. Here, we test the hypothesis that crabs in larger clusters will emerge faster from their shells after an elicited startle response in the European hermit crab (Pagurus bernhardus). We found that individuals were generally consistent in their emergence times across group sizes (displaying ‘personality’ in relation to emergence time), but that group size influenced emergence time in P. bernhardus. In contrast to the hypothesis, crabs in larger clusters had longer emergence times relative to their own emergence times in smaller clusters. Suggested explanations for this effect include intra-specific competition for the gastropod shells that hermit crabs inhabit, as well as the possible release of chemical cues by crabs in larger clusters.

• Journal Article Type: Article
• Publication Date: Jan 1, 2019
• Journal: Bioscience Horizons: The International Journal of Student Research
• Print ISSN: 1754-7431
• Publisher: Oxford University Press (OUP)
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Article Number: hzy011
• APA6 Citation: Broadhurst, H. E., & Morrell, L. J. (2019). Group size and individual ‘personality’ influence emergence times in hermit crabs. Bioscience Horizons, 11, doi:10.1093/biohorizons/hzy011
• DOI: https://doi.org/10.1093/biohorizons/hzy011
• Keywords: Hermit crabs; Emergence time; Personality; Group size; Behavioural consistency; Pagurus bernhardus
• Publisher URL: https://academic.oup.com/biohorizons/article/doi/10.1093/biohorizons/hzy011/5253902