Therry L, Nilsson-Örtman V, Bonte D, Stoks R
Laboratory of Aquatic Ecology, Evolution and Conservation, KU Leuven, Leuven, Belgium.
Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.
J Evol Biol. 2014 Jan;27(1):141-52. doi: 10.1111/jeb.12281. Epub 2013 Dec 7.
Although a growing number of studies have documented the evolution of adult dispersal-related traits at the range edge of poleward-expanding species, we know little about evolutionary changes in immune function or traits expressed by nondispersing larvae. We investigated differentiation in larval (growth and development) and adult traits (immune function and flight-related traits) between replicated core and edge populations of the poleward-moving damselfly Coenagrion scitulum. These traits were measured on individuals reared in a common garden experiment at two different food levels, as allocation trade-offs may be easier to detect under energy shortage. Edge individuals had a faster larval life history (growth and development rates), a higher adult immune function and a nearly significant higher relative flight muscle mass. Most of the differentiation between core and edge populations remained and edge populations had a higher relative flight muscle mass when corrected for latitude-specific thermal regimes, and hence could likely be attributed to the range expansion process per se. We here for the first time document a higher immune function in individuals at the expansion front of a poleward-expanding species and documented the rarely investigated evolution of faster life histories during range expansion. The rapid multivariate evolution in these ecological relevant traits between edge and core populations is expected to translate into changed ecological interactions and therefore has the potential to generate novel eco-evolutionary dynamics at the expansion front.
尽管越来越多的研究记录了在向极地扩展的物种的分布范围边缘与成年扩散相关的性状的演变，但我们对免疫功能或非扩散幼虫所表现出的性状的进化变化知之甚少。我们调查了向北移动的豆娘细纹腹鳃蟌的核心和边缘种群在幼虫（生长和发育）及成年性状（免疫功能和飞行相关性状）方面的差异。这些性状是在一个共同花园实验中，在两种不同食物水平下对个体进行测量的，因为在能量短缺的情况下，分配权衡可能更容易被检测到。边缘种群的个体具有更快的幼虫生活史（生长和发育速率）、更高的成年免疫功能以及相对飞行肌肉质量几乎显著更高。在考虑了特定纬度的热状况后，核心和边缘种群之间的大部分差异仍然存在，并且边缘种群具有更高的相对飞行肌肉质量，因此这很可能归因于范围扩展过程本身。我们首次记录了在向极地扩展的物种的扩展前沿个体具有更高的免疫功能，并记录了在范围扩展期间很少被研究的更快生活史的进化。边缘和核心种群之间这些与生态相关的性状的快速多变量进化预计会转化为改变的生态相互作用，因此有可能在扩展前沿产生新的生态进化动态。
