Data from: Sex differences in the predictability of risk-taking behaviour

Recent research has found that individuals often vary in how consistently they express their behaviour over time (i.e. behavioural predictability) and suggested that these individual differences may be heritable. However, little is known about the intrinsic factors that drive variation in the predictability of behaviour. Indeed, whether variation in behavioural predictability is sex-specific is not clear. This is important, as behavioural predictability has been associated with vulnerability to predation, suggesting that the predictability of behavioural traits may have key fitness implications. We investigated whether male and female eastern mosquitofish (Gambusia holbrooki) differed in the predictability of their risk-taking behaviour. Specifically, over a total of 954 behavioural trials, we repeatedly measured risk-taking behaviour with three commonly used assays—refuge-use, thigmotaxis, and foraging latency. We predicted that there would be consistent sex differences in both mean-level risk-taking behaviour and behavioural predictability across the assays. We found that risk-taking behaviour was repeatable within each assay, and that some individuals were consistently bolder than others across all three assays. There were also consistent sex differences in mean-level risk-taking behaviour, with males being bolder across all three assays compared to females. In contrast, both the magnitude and direction of sex differences in behavioural predictability were assay specific. Taken together, these results highlight that behavioural predictability may be independent from underlying mean-level behavioural traits and suggest that males and females may differentially adjust the consistency of their risk-taking behaviour in response to subtle changes in environmental conditions.

近期研究表明，个体随时间推移的行为表达一致性（即行为可预测性(behavioural predictability)）往往存在个体差异，且此类个体差异可能具有可遗传性。然而，目前学界对驱动行为可预测性差异的内在因素仍知之甚少。事实上，行为可预测性的差异是否存在性别特异性，目前尚无定论。

这一点至关重要，因为行为可预测性与被捕食风险相关，这意味着行为性状的可预测性可能对进化适合度(fitness)具有关键影响。我们以东部食蚊鱼（Gambusia holbrooki）为研究对象，探究雌雄个体在冒险行为的可预测性上是否存在差异。具体而言，在总计954次行为实验中，我们通过三种常用的行为测定范式——避难利用(refuge-use)、趋触性(thigmotaxis)以及觅食潜伏期(foraging latency)——反复测定了受试个体的冒险行为。

我们预设，在所有三种测定范式中，个体的平均冒险行为水平与行为可预测性均会存在稳定的性别差异。研究结果显示，每种测定范式内的冒险行为均具有重复性，且部分个体在全部三种范式中均表现得比其他个体更为大胆。此外，个体的平均冒险行为水平确实存在稳定的性别差异：相较于雌性，雄性在全部三种范式中均表现得更大胆。与之相反，行为可预测性的性别差异的幅度与方向均因测定范式而异。

整合来看，本研究结果表明，行为可预测性可能与个体潜在的平均行为性状相互独立，同时也提示雌雄个体可能会根据环境条件的细微变化，对自身冒险行为的一致性进行差异化调整。