Range expansion, habitat use and choosiness in a butterfly under climate change: marginality and tolerance of oviposition site selection

Poleward range shifts under climate change involve the colonization of new sites and hence the foundation of new populations at the expanding edge. We studied oviposition site selection in a butterfly under range expansion (Lycaena dispar), a key process for the establishment of new populations. We described and compared the microhabitats used by the species for egg laying with those available across the study sites both in edge and in core populations. We carried out an ecological niche factor analysis (ENFA) to estimate (1) the variety of microhabitats used by the butterfly for egg laying (tolerance) and (2) the extent to which these selected microhabitats deviated from those available (marginality). Microhabitat availability was similar in edge and core populations. Ambient temperature recorded at the site level above the vegetation was on average lower at core populations. In contrast with what is often assumed, edge populations did not have narrower microhabitat use compared to cor...气候变化下物种分布范围向极地偏移的过程，涉及对新生境的定殖，进而在扩张前沿建立新种群。本研究以处于分布范围扩张过程中的荨麻灰蝶（Lycaena dispar）为研究对象，探讨其产卵位点选择行为——这是新种群建立的关键过程。我们描述并比较了该物种产卵时所利用的微生境，以及研究样地内前沿种群与核心种群周边可获取的微生境。我们采用生态位因子分析（ENFA），旨在估算两项指标：一是该灰蝶产卵所利用的微生境多样性（即耐受宽度）；二是所选微生境与可利用微生境之间的偏离程度（即边际性）。前沿种群与核心种群的可利用微生境丰度相似。在植被上方的样地尺度下测得的环境温度，核心种群区域的平均温度更低。与普遍认知相悖的是，前沿种群的微生境利用宽度并未比核心种群更窄……