Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France.
Institut de Recherche sur la Biologie de l'Insecte, UMR 7261 CNRS, University of Tours, Tours, France.
J Therm Biol. 2024 Jul;123:103930. doi: 10.1016/j.jtherbio.2024.103930. Epub 2024 Aug 5.
Thermal limits are often used as proxies to assess the vulnerability of ectotherms to environmental change. While meta-analyses point out a relatively low plasticity of heat limits and a large interspecific variability, only few studies have compared the heat tolerance of interacting species. The present study focuses on the thermal limits, and their plasticity (heat hardening), of three species co-occurring in Western Africa: two ectoparasitoid species, Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae) and Eupelmus vuilleti (Crawford) (Hymenoptera: Eupelmidae), and their common host, Callosobruchus maculatus (F.) (Coleoptera: Bruchidae). The investigation delves into the Critical Thermal Maximum (CTmax), representing the upper tolerance limit, to understand how these species may cope with extreme thermal events. The CTmax of all three species appeared similarly high, hovering around 46.5 °C, exceeding the global mean CTmax observed in insects by 3.5 °C. Short-term exposure to moderate heat stress showed no impact on CTmax, suggesting a potential lack of heat hardening in these species. Therefore, we emphasized the similarity of heat tolerance in these interacting species, potentially stemming from both evolutionary adaptations to high temperatures during development and the stable and similar microclimate experienced by the three species over the years. While the high thermal tolerance should allow these species to endure extreme temperature events, the apparent lack of plasticity raises concerns about their ability to adapt to future climate change scenarios. Overall, this research provides valuable insights into the thermal physiology of these interacting species, providing a basis for understanding their responses to climate change and potential implications for the host-parasitoid system.
热极限通常被用作评估变温动物对环境变化脆弱性的替代指标。尽管荟萃分析指出热极限的可塑性相对较低，种间变异性较大，但只有少数研究比较了相互作用物种的耐热性。本研究关注三种共同存在于西非的物种的热极限及其可塑性（热驯化）：两种外寄生性物种，Dinarmus basalis（Rondani）（膜翅目：Pteromalidae）和 Eupelmus vuilleti（Crawford）（膜翅目：Eupelmidae），以及它们的共同宿主 Callosobruchus maculatus（F.）（鞘翅目：Bruchidae）。该研究深入探讨了代表上限耐受性的临界热最大值（CTmax），以了解这些物种如何应对极端热事件。这三个物种的 CTmax 似乎都非常高，徘徊在 46.5°C 左右，比昆虫的全球平均 CTmax 高 3.5°C。短期暴露于适度热应激对 CTmax 没有影响，表明这些物种可能缺乏热驯化。因此，我们强调了这些相互作用物种耐热性的相似性，这可能源于发育过程中对高温的进化适应以及这三个物种多年来经历的稳定且相似的小气候。虽然高耐热性应该使这些物种能够耐受极端温度事件，但明显缺乏可塑性引起了对它们适应未来气候变化情景能力的担忧。总的来说，这项研究为这些相互作用物种的热生理学提供了有价值的见解，为了解它们对气候变化的反应以及对宿主-寄生系统的潜在影响提供了基础。
