As a non-native species invades a new region, individuals at the range front are often characterised by differences in their traits and behaviours versus individuals in the established ‘core’ area. Here, differences in life history traits of invading pumpkinseed Lepomis gibbosus were assessed across a fine spatial scale in the Sarıçay Stream, Turkey, with seven locations sampled between their core area and the invasion front. Following genetic analyses that suggested the pumpkinseed all originated from the same founding population, life history trait analyses revealed pronounced differences between the sites at the core and front that were independent of environmental factors. Pumpkinseed in sites towards the invasion front were of relatively low abundance and displayed relatively high reproductive investment, with heavier gonads, higher fecundity and smaller eggs. They also had faster growth rates than pumpkinseed in sites towards the core of the invasion. The traits displayed by pumpkinseed at sites in the mid-range were intermediate between the extremes displayed by fish at core and frontal sites. These results suggested high plasticity in life history traits of these pumpkinseed across this fine-scale invasion gradient and was considered to be most likely due to responses to low intra-specific competition at the invasion front that had shifted selective pressures towards higher investment in somatic growth and reproduction.

当非本地物种入侵一个新区域时，处于前沿的个体通常以其特征和行为与已建立的“核心”区域中的个体的差异为特征。在这里，入侵南瓜籽Lepomis gibbosus的生活史特征的差异在土耳其Sarıçay溪流的精细空间范围内进行了评估，并在其核心区域和入侵前沿之间采样了七个位置。遗传分析表明南瓜籽都起源于同一创始种群，生活史特征分析表明，核心和前沿部位之间存在明显的差异，而与环境因素无关。入侵前部的南瓜子丰度较低，生殖投资较高，性腺较重，繁殖力较高，卵较小。与入侵地区核心地区的南瓜籽相比，它们的生长速度也更快。南瓜籽在中距离部位显示的特征介于鱼类在核心和额叶部位表现出的极端之间。