Dahirel Maxime, Wullschleger Marie, Berry Tristan, Croci Solène, Pétillon Julien
Univ Rennes, UR1, CNRS, Ecosystèmes, Biodiversité, Évolution (ECOBIO), UMR 6553, F-35000 Rennes, France.
Department of Biology, Ghent University, B-9000 Ghent, Belgium.
Curr Zool. 2022 Mar 9;69(1):21-31. doi: 10.1093/cz/zoac016. eCollection 2023 Feb.
Dispersal and its evolution play a key role for population persistence in fragmented landscapes where habitat loss and fragmentation increase the cost of between-habitat movements. In such contexts, it is important to know how variation in dispersal and other traits is structured, and whether responses to landscape fragmentation are aligned with underlying dispersal-trait correlations, or dispersal syndromes. We, therefore, studied trait variation in , a European spider species specialist of (often patchy) salt marshes. We collected spiders in two salt-marsh landscapes differing in habitat availability. We then reared lab-born spiders for two generations in controlled conditions, and measured dispersal and its association with various key traits. population densities were lower in the more fragmented landscape. Despite this, we found no evidence of differences in dispersal, or any other trait we studied, between the two landscapes. While a dispersal syndrome was present at the among-individual level (dispersers were more fecund and faster growing, among others), there was no indication it was genetically driven: among-family differences in dispersal were not correlated with differences in other traits. Instead, we showed that the observed phenotypic covariations were mostly due to within-family correlations. We hypothesize that the dispersal syndrome is the result of asymmetric food access among siblings, leading to variation in development rates and carrying over to adult traits. Our results show we need to better understand the sources of dispersal variation and syndromes, especially when dispersal may evolve rapidly in response to environmental change.
扩散及其进化对于破碎化景观中种群的持续存在起着关键作用，在这种景观中，栖息地丧失和破碎化增加了栖息地间移动的成本。在这种情况下，了解扩散和其他性状的变异是如何构建的，以及对景观破碎化的反应是否与潜在的扩散性状相关性或扩散综合征一致，是很重要的。因此，我们研究了一种欧洲蜘蛛物种（通常是斑块状）盐沼的性状变异。我们在两种栖息地可利用性不同的盐沼景观中收集蜘蛛。然后，我们在受控条件下将实验室出生的蜘蛛饲养两代，并测量扩散及其与各种关键性状的关联。在破碎化程度更高的景观中，种群密度较低。尽管如此，我们没有发现两种景观之间在扩散或我们研究的任何其他性状上存在差异的证据。虽然在个体水平上存在扩散综合征（例如，扩散者繁殖力更强、生长更快），但没有迹象表明它是由基因驱动的：家庭间在扩散上的差异与其他性状的差异没有相关性。相反，我们表明观察到的表型协变大多是由于家庭内部的相关性。我们推测扩散综合征是兄弟姐妹间食物获取不对称的结果，导致发育速度的差异并延续到成体性状。我们的结果表明，我们需要更好地理解扩散变异和综合征的来源，特别是当扩散可能因环境变化而迅速进化时。
