Department of Biology, Aarhus University, 8000 Aarhus C, Denmark.
Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg E, Denmark.
Proc Biol Sci. 2023 Sep 13;290(2006):20230985. doi: 10.1098/rspb.2023.0985. Epub 2023 Sep 6.
Metabolic compensation has been proposed as a mean for ectotherms to cope with colder climates. For example, under the metabolic cold adaptation and the metabolic homeostasis hypotheses (MCA and MHH), it has been formulated that cold-adapted ectotherms should display both higher (MCA) and more thermally sensitive (MHH) metabolic rates (MRs) at lower temperatures. However, whether such compensation can truly be associated with distribution, and whether it interplays with cold tolerance to predict species' climatic niches, remains largely unclear despite broad ecological implications thereof. Here, we teased apart the relationship between MRs, cold tolerance and distribution, to test the MCA/MHH among 13 European ant species. We report clear metabolic compensation effects, consistent with the MCA and MHH, where MR parameters strongly correlated with latitude and climatic factors across species' distributions. The combination of both cold tolerance and MRs further upheld the best predictions of species' environmental temperatures and limits of northernmost distribution. To our knowledge, this is the first study showing that the association of metabolic data with cold tolerance supports better predictive models of species' climate and distribution in social insects than models including cold tolerance alone. These results also highlight that adaptation to higher latitudes in ants involved adjustments of both cold tolerance and MRs, to allow this extremely successful group of insects to thrive under colder climates.
代谢补偿被认为是变温动物适应寒冷气候的一种手段。例如，在代谢冷适应和代谢内稳假说（MCA 和 MHH）中，人们认为，适应寒冷的变温动物在较低温度下应该表现出更高的（MCA）和更热敏的（MHH）代谢率（MR）。然而，尽管代谢补偿具有广泛的生态意义，但它是否真的与分布有关，以及它是否与耐寒性相互作用来预测物种的气候小生境，在很大程度上仍不清楚。在这里，我们分离了 MR、耐寒性和分布之间的关系，以测试 13 种欧洲蚂蚁物种中的 MCA/MHH。我们报告了明显的代谢补偿效应，与 MCA 和 MHH 一致，其中 MR 参数与物种分布范围内的纬度和气候因素强烈相关。耐寒性和 MRs 的结合进一步支持了物种环境温度和最北分布极限的最佳预测。据我们所知，这是第一项表明代谢数据与耐寒性的关联支持比仅包括耐寒性的模型更好地预测社会性昆虫的气候和分布的研究。这些结果还强调，蚂蚁对更高纬度的适应涉及到耐寒性和 MRs 的调整，以使这个极其成功的昆虫群体在更寒冷的气候中茁壮成长。
