Chill-tolerant Gryllus crickets maintain ion balance at low temperatures
Chill-tolerant Gryllus crickets maintain ion balance at low temperatures
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DOI：
10.1016/j.jinsphys.2015.03.015
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发表时间：
2015-06-01
影响因子：
2.2
通讯作者：
Sinclair, Brent J.
中科院分区：
文献类型：
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作者：
Alvarado, Litza E. Coello;MacMillan, Heath A.;Sinclair, Brent J.
昆虫的耐寒性具有表型可塑性和进化不稳定性，但这种变异的机制尚不确定。寒冷易感昆虫在寒冷中失去离子和水分平衡，这有助于伤害和最终死亡的发展。因此，我们假设更耐寒的昆虫在低温下能更好地维持离子和水的平衡。采用快速冷硬化（RCH）和冷驯化（Glyllus veletis）两种方法提高了雄性灰蚜的耐寒性，并将其与耐冷亲缘种灰蚜进行了比较。冷驯化和RCH降低了柠条的临界热最小值（CTmin）和冷昏迷恢复时间（CCR），但冷驯化提高了0 ~ 0℃的存活率，RCH没有提高；鹅毛苣苔的耐寒性始终高于鹅毛苣苔（CCR和CTmin均低于鹅毛苣苔）。在低温环境下，血淋巴水和Ne迁移到温暖驯化的宾夕法尼亚沼虾肠道，导致血淋巴[K+]升高，肌肉K+平衡电位降低。相比之下，冷驯化的宾夕法尼亚田鼠在冷暴露过程中离子和水分平衡的损失较小，而这种再分配在冷暴露的鹅毛田鼠中根本没有发生。离子和水分平衡的丧失在RCH和暖驯化的宾夕法尼亚大戟之间相似，这表明与0℃下存活率的提高相比，CCR和CTmin的降低存在不同的机制。我们得出结论，抗寒能力的增强与低温下离子和水分平衡的维持改善有关，这与表型可塑性和进化的抗寒性是一致的。(C) 2015 Elsevier Ltd.版权所有。
Insect cold tolerance is both phenotypically-plastic and evolutionarily labile, but the mechanisms underlying this variation are uncertain. Chill-susceptible insects lose ion and water homeostasis in the cold, which contributes to the development of injuries and eventually death. We thus hypothesized that more cold-tolerant insects will better maintain ion and water balance at low temperatures. We used rapid cold-hardening (RCH) and cold acclimation to improve cold tolerance of male Gryllus pennsylvanicus, and also compared this species to its cold-tolerant relative (Glyllus veletis). Cold acclimation and RCH decreased the critical thermal minimum (CTmin) and chill coma recovery time (CCR) in G. pennsylvanicus, but while cold acclimation improved survival of 0 0 degrees C, RCH did not; G. veletis was consistently more cold-tolerant (and had lower CCR and CTmin) than G. pennsylvanicus. During cold exposure, hemolymph water and Ne migrated to the gut of warm-acclimated G. pennsylvanicus, which increased hemolymph [K+] and decreased muscle K+ equilibrium potentials. By contrast, cold-acclimated G. pennsylvanicus suffered a smaller loss of ion and water homeostasis during cold exposure, and this redistribution did not occur at all in cold-exposed G. veletis. The loss of ion and water balance was similar between RCH and warm-acclimated G. pennsylvanicus, suggesting that different mechanisms underlie decreased CCR and CTmin compared to increased survival at 0 degrees C. We conclude that increased tolerance of chilling is associated with improved maintenance of ion and water homeostasis in the cold, and that this is consistent for both phenotypic plasticity and evolved cold tolerance. (C) 2015 Elsevier Ltd. All rights reserved.