Lefort Marie-Caroline, Brown Samuel, Boyer Stéphane, Worner Susan, Armstrong Karen
Bio-Protection Research Centre, Lincoln University , Lincoln, Christchurch , New Zealand.
Bio-Protection Research Centre, Lincoln University , Lincoln, Christchurch , New Zealand ; Department of Ecology, Faculty of Agricultural and Life Sciences, Lincoln University , Lincoln , New Zealand.
PeerJ. 2014 Nov 25;2:e676. doi: 10.7717/peerj.676. eCollection 2014.
In the field of invasion ecology, the determination of a species' environmental tolerance, is a key parameter in the prediction of its potential distribution, particularly in the context of global warming. In poikilothermic species such as insects, temperature is often considered the most important abiotic factor that affects numerous life-history and fitness traits through its effect on metabolic rate. Therefore the response of an insect to challenging temperatures may provide key information as to its climatic and therefore spatial distribution. Variation in the phosphoglucose-6-isomerase (PGI) metabolic enzyme-system has been proposed in some insects to underlie their relative fitness, and is recognised as a key enzyme in their thermal adaptation. However, in this context it has not been considered as a potential mechanism contributing to a species invasive cability. The present study aimed to compare the thermal tolerance of an invasive scarabaeid beetle, Costelytra zealandica (White) with that of the closely related, and in part sympatrically occurring, congeneric non-invasive species C. brunneum (Broun), and to consider whether any correlation with particular PGI genotypes was apparent. Third instar larvae of each species were exposed to one of three different temperatures (10, 15 and 20 °C) over six weeks and their fitness (survival and growth rate) measured and PGI phenotyping performed via cellulose acetate electrophoresis. No consistent relationship between PGI genotypes and fitness was detected, suggesting that PGI may not be contributing to the invasion success and pest status of C. zealandica.
在入侵生态学领域，确定一个物种的环境耐受性是预测其潜在分布的关键参数，特别是在全球变暖的背景下。在昆虫等变温动物中，温度通常被认为是最重要的非生物因素，它通过影响代谢率来影响众多生活史和适合度特征。因此，昆虫对挑战性温度的反应可能提供有关其气候及空间分布的关键信息。在一些昆虫中，已提出磷酸葡萄糖 -6-异构酶（PGI）代谢酶系统的变异是其相对适合度的基础，并且被认为是它们热适应的关键酶。然而，在这种情况下，它尚未被视为有助于物种入侵能力的潜在机制。本研究旨在比较入侵性金龟子科甲虫新西兰肋翅鳃金龟（Costelytra zealandica (White)）与亲缘关系密切且部分同域分布的同属非入侵物种布鲁氏肋翅鳃金龟（C. brunneum (Broun)）的耐热性，并考虑是否存在与特定PGI基因型的明显相关性。每个物种的三龄幼虫在六周内暴露于三种不同温度（10、15和20°C）之一，测量它们的适合度（存活率和生长率），并通过醋酸纤维素电泳进行PGI表型分析。未检测到PGI基因型与适合度之间的一致关系，这表明PGI可能对新西兰肋翅鳃金龟的入侵成功和害虫地位没有贡献。
