Size specific boldness associated with differences in resource requirements and habitat use: A cross-sectional study in hermit crabs

Abstract

<jats:title>Abstract</jats:title> <jats:p>Animal personality is often studied within compressed periods of observation that represent narrow windows in comparison to animal lifespans. While much is known about the relations between repeatable personality traits and cross-situational behavioural plasticity, less is known about how such traits might differ across age classes or life-history transitions. We conducted a cross-sectional study of startle response duration in three size classes of Pagurus bernhardus, the common European hermit crab. We defined size classes using transitions in the preferred species of gastropod shells that accompany growth, and this change in preference is in turn associated with a transition from intertidal to subtidal habitats. Compared to small and medium sized intertidal individuals the larger subtidal hermit crabs behaved cautiously by showing startle responses of greater duration following disturbance. Startle responses were also repeatable within all three size classes, confirming the presence of animal personality in intertidal hermit crabs and demonstrating that this pattern is retained within the largest size classes, that have undergone the transition from intertidal to subtidal habitat. Interestingly, there was a trend for the pattern of repeatable startle response durations to increase with size class, with the highest value for repeatability and greatest range of startle response durations being present within the large subtidal population. The greater range of startle responses indicates that the longer startle response durations in some larger individuals are more likely due to developmental changes with age and habitat use than reflecting selection against the boldest individuals during earlier stages of life.</jats:p>