Correlazione tra personalità ed ontogenesi del ragno Pisaura mirabilis

Recent years have seen a growing interest in the field of animal personality, defined as individual behavioral responses that are constant over time in different contexts. Personality varies among individuals of the same species in relation to both extrinsic and intrinsic factors, such as sex. These differences can be observed in numerous animal taxa: from mammals to birds and fish, and invertebrate groups such as insects and arachnids. What remains poorly understood is if individual variation in behaviour varies during ontogeny. In particular, this thesis aims to test whether two personality traits (exploration and aggressiveness) of the spider Pisaura mirabilis vary with ontogeny and sex. Individuals were tested repeatedly during 3 ontogenetic phases: as juveniles, subadults and adults. I measured exploration as the time spent exploring a new environment and aggressiveness as a response to an external stimulus, in this case a poke with a paintbrush. Both tests were repeated at least three times on three different days for each individual within the same ontogenetic stage. The results don’t denote a strong correlation between ontogenetic stage and personality, while emphasizing the sex-related effect. In fact, we found that males express greater exploration and females higher aggressiveness and we discuss our results in light of the reproductive biology of the species, where males hunt for prey that is donated in the form of a nuptial gift to cannibalistic females.