Fear, food, sex and parental care: a syndrome of boldness in the fishing spider, Dolomedes triton

We studied individual variation in the antipredator response of the fishing spider, D. triton, in a variety of developmental and behavioural contexts. We examined our data with respect to two general hypotheses: (1) startled spiders should modulate their boldness according to context-specific variables (e.g. developmental stage, feeding opportunities, mating opportunities, parental investment, body condition, etc.), and/or (2) an individual spider's boldness will be consistent (i.e. positively correlated) across contexts such that boldness in any given context is well predicted by boldness in other contexts. We found some support for the former, context-specific hypothesis and strong support for the latter, ‘behavioural-syndromes’ hypothesis. While spiders were significantly bolder in the presence versus absence of prey, boldness did not fluctuate with developmental stage, mating opportunities, parental investment or condition in the manner predicted. Instead, boldness in adult spiders was well predicted by a syndrome of positively correlated bold behaviours across functional contexts. We suggest that animal behaviour most often reflects a combination of context-specific behavioural optimization and context-general expression of behavioural syndromes, as was seen in this experiment. We further suggest that disentangling the relative magnitude of these two general mechanisms in a wide variety of taxa, covering many behavioural-ecological contexts, will provide great insights into (1) population ecology (e.g. the success of invasive/pest species and the failure of threatened species), (2) community ecology (e.g. species coexistence, trophic dynamics), and (3) evolutionary ecology (e.g. evolution of the multivariate behavioural phenotype).