Differences in environmental enrichment generate contrasting behavioural syndromes in a basal spider lineage

Behavioural syndrome studies are commonly descriptive and often find a relationship between boldness, shyness and exploration. However, the mechanisms underlying behavioural syndromes are not well understood. In the present study, we examined the extent to which early experience acts as a modifier of behavioural tendencies in the basal tarantula, Brachypelma smithi. Juvenile individuals were housed for 2 years either in enriched controlled conditions, or in restricted (minimal) conditions. Behavioural assays were completed both in short-term and in long-term increments. We found both short-term and long-term differences in multiple contexts of behaviour between treatments. In addition, individuals in the enriched treatment developed correlations between several behavioural traits whereas individuals in the restricted treatment did not. This result suggests that early environment can induce behavioural syndromes in some populations, or conversely, that continual stress may break down normal behavioural development and thus prevent a behavioural syndrome from emerging. This study provides a cautionary tale for those studying behavioural syndromes in captivity, and because this is a basal spider species, it provides important insight into the evolution of spider behavioural syndromes.