Abstract

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.

Significance statement

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.

中文翻译：

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尾巴切开术与雄性但不雄性的女性大胆相关

摘要

人格特质的性别差异（例如大胆）通常是由生活史策略的差异所驱动。具体而言，在多性交配系统中，雄性捍卫领土以获取配偶，与雌性相比，雄性表现出更高的勇气可能是有益的。然而，由于雄性行为，雄性可能也遭受更高的代价。但是，很少有研究记录两性之间大胆付出代价的证据。我们研究了水an（Anolis aquaticus），使用尾巴切开术代替种内竞争引起的捕食风险和/或伤害。我们将勇敢程度衡量为从庇护所进入新环境的潜伏期。我们预测（1）雄性比雌性表现出更大胆的行为，（2）胆大与尾巴切开呈正相关（即，有尾巴切尾的蜥蜴比没有尾巴切开的蜥蜴大胆），以及（3）与女性相比，较高比例的男性会表现出尾部自切的证据。我们发现，在行为测试中，（1）男女之间的大胆性没有差异，但（2）在大胆性的代价上存在性别差异，因此，雄性与男性的尾巴截肢呈正相关，而女性则没有。 （3）男性倾向于表现出尾部自体解剖的证据。一起，

重要性声明

性别通常在行为上有所不同，因为男性和女性使用不同的策略来实现生殖成功。大胆是一种人格特质，在获取资源方面对男女双方都有利。但是，勇敢应给男性保卫领土和竞争伴侣带来更多好处。尽管大胆行为的代价是什么，这在男女之间有区别吗？在这里，我们发现，胆大与男性水an风险引发的伤害（尾巴脱落）有关，而与女性水not则无关。事实证明，失去尾巴会对蜥蜴产生严重的健身后果。因此，雄性水母的胆大行事代价要高于雌性。我们的结果提供了关于胆量与生态相关性的见解，以及选择如何导致性别之间的性格差异。