Assessment of intra-individual consistency of physiology and behaviour in brachyuran crabs (Carcinus maenas and Cancer irroratus)

Abstract

Physiology and behaviour are labile (i.e., flexible) traits with a wide intra-individual reaction scope, nonetheless individuals often exhibit consistent and predictable responses when repeatedly tested. Consistent individual-level differences in behaviour are studied as animal personality, and according to the pace-of-life syndrome hypothesis, personality differences co-vary with differences in metabolic rate. So far, much of the literature on this relationship is theoretical and based on a limited set of taxa. While experimental evidence is accumulating, the results are equivocal. Because labile traits are highly susceptible to environmental change, the lack of standardization in experimental procedures makes interpreting results from different studies complicated. My overarching thesis objective was to experimentally test the relationship between physiology and behaviour in two common species of bracyuran crab (Cancer irroratus and Carcinus maenas), and quantify the effects of common lab stressors on labile trait expression. In Chapter 2, I assess the presence of personalities and behavioural syndromes, and determine if inter-individual variation in metabolic rate can explain differences in personality. In Chapter 3, I quantify the effects of common lab stressors (prolonged lab holding, transfer into experimental chambers, and a homogenous diet) on the short- and long-term changes in crab labile traits.