Zhao Fei, Hoffmann Ary A, Xing Kun, Ma Chun-Sen
Shanxi Key Laboratory of Integrated Pest Management in Agriculture, Institute of Plant Protection, Shanxi Academy of Agricultural Sciences, 81 Longcheng Street, CN-030031 Taiyuan, PR China; Climate Change Biology Research Group, State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, 2 Yuanmingyuan West Road, CN-100193 Beijing, PR China.
Pest and Disease Vector Group, School of BioSciences, Bio21 Institute, The University of Melbourne, 30 Flemington Road, Melbourne, Vic. 3010, Australia.
J Insect Physiol. 2017 May;99:1-7. doi: 10.1016/j.jinsphys.2017.03.003. Epub 2017 Mar 8.
Heat responses can vary ontogenetically in many insects with complex life cycles, reflecting differences in thermal environments they experience. Such variation has rarely been considered in insects that develop incrementally and experience common microclimates across stages. To test if there is a low level of ontogenetic variation for heat responses in one such species, the English grain aphid Sitobion avenae, basal tolerance [upper lethal temperature (ULT) and maximum critical temperature (CT)], hardening capacity (CT) and hardening costs (adult longevity and fecundity) were measured across five stages (1st, 2nd, 3rd and 4th-instar nymphs and newly moulted adults). We found large tolerance differences among stages of this global pest species, and a tendency for the stage with lower heat tolerance to show a stronger hardening response. There were also substantial reproductive costs of hardening responses, with the level of stress experienced, and not the proximity of the exposed stage to the reproductive adult stage, influencing the magnitude of this cost. Hence hardening in this aphid may counter inherently low tolerance levels of some life stages but at a cost to adult longevity and fecundity. Our findings highlight the significance of ontogenetic variation in predicting responses of a species to climate change, even in species without a complex life cycle.
在许多具有复杂生命周期的昆虫中，热反应可能会在个体发育过程中有所不同，这反映了它们所经历的热环境的差异。在渐进发育且各阶段经历共同小气候的昆虫中，这种变化很少被考虑。为了测试在这样一个物种——英国谷物蚜虫麦长管蚜（Sitobion avenae）中热反应的个体发育变化水平是否较低，我们在五个阶段（一龄、二龄、三龄和四龄若虫以及新羽化的成虫）测量了基础耐受性[上限致死温度（ULT）和最高临界温度（CT）]、硬化能力（CT）和硬化成本（成虫寿命和繁殖力）。我们发现这种全球害虫物种的不同阶段之间存在很大的耐受性差异，并且耐热性较低的阶段往往表现出更强的硬化反应。硬化反应也存在大量的繁殖成本，所经历的压力水平而非暴露阶段与生殖成虫阶段的接近程度影响了这种成本的大小。因此，这种蚜虫的硬化可能会抵消某些生命阶段固有的低耐受性水平，但会以成虫寿命和繁殖力为代价。我们的研究结果强调了个体发育变化在预测一个物种对气候变化的反应中的重要性，即使是在没有复杂生命周期的物种中。
