Condition, dispersal, and population connectivity of two butterfly species in agricultural landscapes

由于物种灭绝和人口数量的减少，地球的生物多样性目前正在下降。近年来，几项研究记录了昆虫的大量减少，特别是在农业景观中。这种损失可能会通过减少生物多样性提供的商品和服务而对生态系统和人类社会产生反馈。虽然昆虫大规模减少的证据正在迅速增加，但其根本原因仍有争议，但到目前为止还没有很好地理解。土地利用集约化一再被认为是一个主要驱动因素，最近的研究表明，昆虫的减少与景观尺度上的农业有关。这意味着栖息地面积和连通性以及扩散和资源可用性的重要作用，到目前为止可能被低估了。利用两种具有不同扩散能力的蝴蝶(Coenonympha PamPhilus，Pieris rapae)，我在这里重点研究农业景观中潜在的昆虫衰退的两个重要方面，即(1)限制扩散的影响和(2)缺乏成年食物(花蜜)资源的影响。两者密切相关，因为花蜜主要是在蝴蝶体内传播的燃料，而传播能力将影响在支离破碎的景观中获得此类资源的可能性。将比较不同土地利用强度和栖息地网络的复制的传统和(高度分散的)现代农业景观的模式。我将使用一种高度集成的方法，结合野外采集、形态和生理分析、普通花园实验、地理信息系统分析和精细景观基因组学。后者使得即使在小的空间尺度上也能够以前所未有的严谨性研究扩散。我将研究(1)蝴蝶条件，(2)飞行形态，(3)飞行能力和倾向，(4)种群遗传结构，(5)代谢途径的变化。不同方法的结合将大大增强我们对农业景观蝴蝶式下降的理解。

The Earth’s biodiversity is currently declining through species extinctions and reductions in population abundances. In recent years, several studies documented massive insect declines, in particular in agricultural landscapes. Such losses will likely feedback on ecosystems and human societies alike, through a reduction in the goods and services biodiversity provides. While the evidence for large-scale insect declines is rapidly increasing, the underlying causes are debated but hitherto not well understood. Land-use intensification has been repeatedly suggested to be a major driver, and recent studies show that insect declines are associated with agriculture at the landscape scale. This implies an important and hitherto probably underestimated role of habitat area and connectivity, and thus dispersal and resource availability. Using two butterfly species with contrasting dispersal ability (Coenonympha pamphilus, Pieris rapae), I here focus on two important aspects potentially underlying insect declines in agricultural landscapes, namely the impact of (1) constraints on dispersal and (2) a lack of adult food (nectar) resources. Both are intimately associated, as nectar largely fuels dispersal in butterflies, while dispersal ability will affect the likelihood of reaching such resources in fragmented landscapes. Patterns will be compared among replicated traditional and (highly fragmented) modern agricultural landscapes, differing in land use intensity and habitat networks. I will use a highly integrated approach combining field collections, morphological and physiological analyses, common garden experiments, GIS analyses, and fine-scale landscape genomics. The latter enables investigating dispersal even at small spatial scales with unprecedented rigour. I will investigate (1) butterfly condition, (2) flight morphology, (3) flight capacity and propensity, (4) population genetic structure, and (5) variation in metabolic pathways. The integration of different approaches will considerably enhance our understanding of butterfly declines in agricultural landscapes.