Urbanisation and sex affect the consistency of butterfly personality across metamorphosis

摘要

Animal behaviour may change with age, when young individuals experience different environments from adults. However, the role of ontogeny in personality traits is still open to debate and it is not clear whether individual differences in behaviour are maintained across important ontogenetic changes such as metamorphosis. Here, we repeatedly quantified personality in rural and urban populations of the speckled wood butterfly (Pararge aegeria) at the larval, pupal and adult stages. We detected significant repeatability at all life stages, showing that personality is already present at the immature stages. We found no evidence for landscape-related differences in personality traits, but adult males were bolder and more active than adult females. Adults also became bolder with trial sequence, suggesting habitation to the experimental procedure. Urbanisation, together with sex, affected relationships among larval and adult personality traits. More active larvae with short latencies resulted in more explorative adults. However, this was the case in males of urban origin only, and we detected no such correlation in females or in rural males. We suggest that harsh conditions prevailing in cities may lead to stronger trait integration across metamorphosis but also that these urbanisation-related selective pressures may act differently on males and females.Significance statementIn many taxa, metamorphosis marks the transition between the juvenile and the adult stages. During this crucial developmental step, morphology and physiology are deeply remodelled, which may have important consequences for the behaviour of individuals. Although personality has emerged as a hot topic in behavioural ecology, little is known about the consequences of metamorphosis for personality stability. We studied rural and urban speckled wood butterflies at the immature and adult stages to examine whether insect personality is retained over metamorphosis. Sexes differed regarding boldness and activity, but rural and urban butterflies behaved similarly. Nevertheless, urbanisation affected relationships among larval and adult personality traits. Some larval and adult traits correlated in urban males, whereas this was not the case in females or in rural males. This suggests that urbanisation may alter trait combinations across metamorphosis, but this in a sex-specific manner.