Tail autotomy is associated with boldness in male but not female water anoles

Sex differences in personality traits, such as boldness, are often driven by differences in life history strategies. Specifically, in a polygynous mating system where males defend territories to acquire mates, it may be beneficial for males to exhibit higher levels of boldness compared to females. However, males may also suffer a higher cost due to their bold behavior. Yet, few studies have documented evidence of the differential costs of boldness between the sexes. We examined these relationships in water anoles (Anolis aquaticus), using tail autotomy as a proxy for predation risk and/or injury from intraspecific competition. We measured boldness as latency to emerge from a refuge into a novel environment. We predicted that (1) males would exhibit bolder behavior than females, (2) boldness would be positively associated with tail autotomy (i.e., lizards with evidence of autotomized tails would be bolder than lizards without evidence of tail autotomy), and (3) a higher proportion of males would exhibit evidence of tail autotomy than females. We found that in our behavioral test, (1) boldness did not differ between the sexes, but that (2) there were sex differences in the costs of boldness, such that boldness was positively associated with tail autotomy in males but not in females, and (3) males tended to be more likely to exhibit evidence of tail autotomy. Together, these results suggest that males may suffer a higher cost of boldness due to sex differences in reproductive strategies. The sexes often differ in behavior because males and females use different tactics to fulfill reproductive success. Boldness is a personality trait that benefits both sexes in terms of acquiring resources. However, boldness should benefit males more when they defend territories and compete for mates. Though what is the cost of bold behavior and does this differ between the sexes? Here, we found that boldness is associated with risk-induced injuries (tail loss) in male water anoles, but not in females. The loss of the tail has been shown to have serious fitness consequences in lizards. Thus, male water anoles suffer a higher cost of bold behavior than females. Our results provide insight on the ecological relevance of boldness, and how selection may have led to differences in personality between the sexes.