Biological invasions and continued salinization of freshwater are two global issues with largely serious ecological consequences. Increasing salinity in freshwater systems, as an environmental stressor, may negatively affect normal life activities in fish. It has been documented that salinity limits the invasive success of alien species by mediating physiological and life-history performances, however, there are few studies on how salinity affects its invasive process via altered behaviors. Using wild-caught invasive western mosquitofish (Gambusia affinis) as animal model, in this study, we asked whether gradual increasing salinity affects behaviors (personality and mate choice decision here), life-history traits, as well as the correlation between them by exposing G. affinis to three levels salinity (freshwater, 10 and 20‰). Results showed that, with increased salinity, male tended to be shyer, less active, less sociable, and reduced desire to mate, and female tended to be shyer, less active and lost preferences for the larger male. Furthermore, across salinity treatments, male exhibited reduced body fat content and rising reproduction allocation, however, pregnant female revealed diametrically opposed trends. In addition, the correlation between life-history traits and behaviors was only identified in pregnant female. It seems that either salinity or life-history traits directly affects mosquitofish behaviors. In summary, our results partially emphasize the harmful consequences of salinity on both life-history traits and behavioral performances. These findings provide a novel perspective on how salinity potentially affect fish fitness via altering personalities, mate choice decisions, as well as body condition, and hence supports the idea that salinity could affect the spread of invasive mosquitofish.

生物入侵和淡水持续盐碱化是两个具有严重生态后果的全球性问题。作为环境压力源，淡水系统中盐度的增加可能会对鱼类的正常生命活动产生负面影响。据记载，盐度通过调节生理和生活史表现来限制外来物种的入侵成功，然而，关于盐度如何通过改变行为影响其入侵过程的研究很少。在这项研究中，我们以野生捕获的入侵性西方蚊鱼 ( Gambusia affinis ) 作为动物模型，通过暴露来询问逐渐增加的盐度是否会影响行为（此处的个性和配偶选择决定）、生活史特征以及它们之间的相关性。G. affinis三级盐度（淡水，10和20‰）。结果表明，随着盐度的增加，雄性往往更害羞、不那么活跃、不善于交际，并减少了交配的欲望，而雌性往往更害羞、不那么活跃，并且对更大的雄性失去了偏好。此外，在盐度处理中，男性表现出体脂含量降低和生殖分配增加，然而，怀孕女性表现出截然相反的趋势。此外，仅在怀孕女性中发现了生活史特征与行为之间的相关性。似乎盐度或生活史特征直接影响蚊鱼的行为。总之，我们的结果部分强调了盐度对生活史特征和行为表现的有害影响。