A key challenge in invasion biology is identifying characteristics that allow some species to be repeatedly successful at invading novel environments. Invasions can often be disproportionately driven by a single sex, with differences in behavioural mechanisms between the sexes potentially underlying sex-biased invasiveness. Here, we took an animal personality approach to study the behaviour of two repeatedly successful congeneric invasive species, the western mosquitofish, Gambusia affinis, and the eastern mosquitofish, Gambusia holbrooki. In each species, we investigated whether males and females shared common personality traits (i.e. behavioural types and behavioural syndromes), with the aim of identifying possible behavioural mechanisms that could help explain why mosquitofish invasions are often characterised by sex-biased founder populations. We found sex-dependent personality, although sex differences varied between species. Male G. affinis were bolder and less social than female G. affinis, whereas we found no behavioural type differences between the sexes in G. holbrooki. We also found a consistent correlation between boldness and exploration in both sexes within G. affinis, but this correlation was weak in G. holbrooki. Finally, exploration was also correlated with sociability in male G. affinis, but not in females. Our results suggest that behavioural tendencies may diverge, both among species and between the sexes, because of adaptation experienced during different invasion pathways. Broadly, identifying the behavioural mechanisms that predict an individual’s ‘invasiveness’ may be difficult to tease apart between species because each invasion is characterised by different abiotic and biotic interactions that likely require different suites of behaviours. Future studies are needed to elucidate whether, in fact, personality variation between the sexes can mediate the occurrence of sex-biased invasions.

中文翻译：

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两种入侵鱼类的性别依赖性人格

入侵生物学中的一个关键挑战是确定允许某些物种在成功入侵新环境中反复获得成功的特征。入侵通常可能是由单性别过分驱动的，而两性之间的行为机制差异可能是潜在的基于性别的入侵。在这里，我们采用一种动物性格方法研究了两个反复成功的同类入侵物种，即西部蚊子（Gambusia affinis）和东部蚊子（Gambusia holbrooki）的行为。。在每个物种中，我们调查了男性和女性是否具有共同的人格特质（即行为类型和行为综合症），目的是确定可能的行为机制，以帮助解释为什么蚊子入侵通常以偏向性别的创始人群体为特征。我们发现性别依赖性人格，尽管物种之间的性别差异也不同。男性G. affinis比女性G. affinis大胆，社交少，但是我们发现在holbrooki的性别之间没有行为类型的差异。我们还发现，在中男女双方的勇气和探索之间的相关性一致G.慈，但这种相关性较弱G. holbrooki。最后，探索也与男性G. affinis的社交能力相关，但与女性无关。我们的研究结果表明，由于在不同入侵途径中所经历的适应，行为倾向可能在物种之间和性别之间有所不同。从广义上讲，识别预测个体“入侵”的行为机制可能很难在物种之间进行区分，因为每次入侵的特征是不同的非生物和生物相互作用，可能需要不同的行为方式。需要进一步的研究来阐明，事实上，两性之间的性格差异是否可以介导性别偏见的侵袭的发生。