Understanding the invasion success of alien species includes developing knowledge on how the biological traits of their populations respond to spatial differences in environmental conditions. For invasive fishes, while the influence of latitudinal and climatic gradients on their biological traits over large spatial scales is well established, there is less certainty in how these vary over smaller scales. Here, we tested the influence of a climatic and geographic gradient on the reproductive traits and body sizes of the invasive mosquitofish Gambusia holbrooki across five climatic regions in Turkey. The results revealed that the environmental conditions across eight sites provided two gradients: a latitudinal gradient (where northern sites were cooler with less rainfall) and a coastal–inland gradient (where changes were apparent from coastal areas and into inland areas). These gradients had marked effects on the traits of both sexes. In sites in coastal and southern areas, males had significantly larger gonopodia and females had greater fecundity than in inland and warmer areas, and with both sexes having body sizes that were smaller. The spatial differences in the male traits were suggested as being driven by differences in selection pressures at the sites that related to differences in their population abundances. The results revealed that environmental conditions across a relatively small spatial scale had some strong influences on the expression of specific biological traits of these mosquitofish populations, but with further work needed to test how these influences affect their invasion success.

了解外来物种的入侵成功包括发展关于其种群的生物学特征如何响应环境条件的空间差异的知识。对于入侵鱼类，虽然纬度和气候梯度对其生物学特征在大空间尺度上的影响已经确立，但它们在较小尺度上如何变化的确定性较低。在这里，我们测试了气候和地理梯度对入侵蚊鱼 Gambusia holbrooki的生殖特征和体型的影响横跨土耳其的五个气候区。结果表明，八个地点的环境条件提供了两个梯度：纬度梯度（北部地点较冷，降雨量较少）和沿海-内陆梯度（从沿海地区到内陆地区的变化明显）。这些梯度对两性的特征都有显着影响。在沿海和南部地区，与内陆和温暖地区相比，雄性的生殖器明显更大，雌性的生殖力更强，而且两性的体型都较小。男性性状的空间差异被认为是由与其种群丰度差异相关的地点的选择压力差异驱动的。