Individual differences in boldness positively correlate with heart rate in orb-weaving spiders of genus Larinioides

Abstract

Abstract Recent years have seen a dramatic increase in the number of studies devoted to consistent individual differences in behavior, termed “behavioral syndromes” or animal “personality”. In particular, ecologists and evolutionary biologists alike seek to explore the functional consequences of individuals’ personalities and explanations for their general maintenance. Understanding the mechanistic underpinnings to personality is arguably key to a deeper understanding of their functional consequences and maintenance. In particular, consistent individual differences in metabolic rate have been proposed as a general explanation for the maintenance of consistent individual differences in boldness, aggressiveness, and activity level. In this paper we explore whether consistent individual differences in boldness are associated with heat rate, a proxy for metabolic rate, in two species of orb-weaving spider: Larinioides cornutus and L. patagiatus. We first documented consistent individual differences in boldness in L. cornutus but not L. patagiatus, as estimated by individuals’ latency to resume movement following an aversive stimulus. We also measured individuals’ heart rate twice in a separate situation. We then tested for an association between individuals’ boldness and their heart rate during these two events. We found that increased boldness was associated with increased heart. Thus, individuals that resumed movement quickly following an aversive stimulus also exhibited faster heart rates. Our studies provide further evidence that consistent individual differences in key physiological attributes, like metabolic rate, might be a general mechanism underlying consistent individual differences in behavior.