SHYNESS AND BOLDNESS IN PUMPKINSEED SUNFISH - INDIVIDUAL-DIFFERENCES ARE CONTEXT-SPECIFIC

Natural selection often promotes a mix of behavioural phenotypes in a population. Adaptive variation in the propensity to take risks might e xplain individual differences in shyness and boldness in humans and ot her species. It is often implicitly assumed that shyness and boldness are general personality traits expressed across many situations. From the evolutionary standpoint, however, individual differences that are adaptive in one context (e.g. predator defence) may not be adaptive in other contexts (e.g. exploration of the physical environment or intra specific social interactions). We measured the context specificity of shyness and boldness in a natural population of juvenile pumpkinseed s unfish, Lepomis gibbosus, by exposing the fish to a potentially threat ening stimulus (a red-tipped metrestick extended towards the individua l) and a nonthreatening stimulus (a novel food source). We also relate d these measures of shyness and boldness to behaviours observed during focal observations, both before and after the introduction of a preda tor (largemouth bass, Micropterus salmoides). Consistent individual di fferences were found within both contexts, but individual differences did not correlate across contexts. Furthermore, fish that were scored as intermediate in their response to the metrestick behaved most boldl y as foragers and in response to the bass predators. These results sug gest that shyness and boldness are context-specific and may not exist as a one-dimensional behavioural continuum even within a single contex t. (C) 1998 The Association for the Study of Animal Behaviour.