Data from: How ants acclimate: impact of climatic conditions on the cuticular hydrocarbon profile

1. Organisms from temperate zones are exposed to seasonal changes and must be able to cope with a wide range of climatic conditions. Especially ectotherms, including insects, are at risk to desiccate under dry and warm conditions, the more so given the changing climate. 2. To adjust to current conditions, organisms acclimate through changes in physiology, morphology and/or behaviour. Insects protect themselves against desiccation through a layer of cuticular hydrocarbons (CHC) on their body surface. Hence, acclimation may also affect the CHC profile, changing their waterproofing capacity under different climatic conditions. 3. Here, we investigated the acclimation response of two Temnothorax ant species to different climatic conditions. We analysed CHC profiles of queens, nurses and foragers that were acclimated to different humidity x temperature regimes, and tested the beneficial acclimation hypothesis by measuring survival of workers under desiccation-heat stress. 4. Both ants possessed a species-specific CHC profile. Nevertheless, they showed similar acclimation responses concerning changes of certain CHC classes, and finally similar survival rates under desiccation-heat stress. Warm-acclimated individuals generally showed longer n-alkanes, fewer dimethyl alkanes, and more (workers) or less (queens) monomethyl alkanes. In contrast, dry conditions resulted in more n-alkanes and fewer mono- and dimethyl alkanes, but these acclimatory changes were only observed in workers and not in queens. Warm- and dry-acclimated workers survived desiccation-heat stress better, but we found no species differences. 5. Our results indicate that both ant species can plastically adjust their cuticular hydrocarbon profile, allowing them to acclimate to different climatic conditions. Although their CHC composition differs in a species-specific manner, they showed similar chemical adjustments and concomitant changes in survival rate. Hence, chemical plasticity may be critical to determine a species’ climatic range and its survival under changing climatic conditions.

1. 温带生物会经历季节更替，必须能够应对多样的气候条件。其中，包括昆虫在内的变温动物（ectotherms）在干燥温暖的环境下面临脱水风险，而气候变化进一步加剧了这一威胁。2. 为适应当前环境，生物可通过生理、形态或行为层面的改变实现驯化（acclimation）。昆虫依靠体表的表皮碳氢化合物（cuticular hydrocarbons, CHC）层抵御脱水。因此，驯化过程也可能影响CHC图谱，进而改变其在不同气候条件下的防水性能。3. 本研究针对两种扁胸切叶蚁属（Temnothorax）蚂蚁对不同气候条件的驯化响应展开探究。我们分析了经不同湿度-温度调控方案驯化后的蚁后、保育工蚁、觅食蚁的CHC图谱，并通过测定工蚁在干燥热胁迫下的存活率，验证了有益驯化假说（beneficial acclimation hypothesis）。4. 两种蚂蚁均具有物种特异性的CHC图谱。尽管如此，二者在部分CHC类别的变化上呈现出相似的驯化响应，最终在干燥热胁迫下的存活率也较为接近。经温暖环境驯化的个体通常拥有更长的正构烷烃（n-alkanes）、更少的二甲基烷烃（dimethyl alkanes），且工蚁体内的单甲基烷烃（monomethyl alkanes）含量升高、蚁后体内则降低。与之相反，干燥环境会使个体体内正构烷烃含量升高、单甲基烷烃与二甲基烷烃含量降低，但这类驯化性变化仅在工蚁中被观测到，蚁后并未出现此类改变。经温暖与干燥环境驯化的工蚁在干燥热胁迫下的存活率更高，但未发现物种间的显著差异。5. 研究结果表明，两种扁胸切叶蚁均能通过表型可塑性调整其表皮碳氢化合物图谱，从而适应不同的气候条件。尽管二者的CHC组成具有物种特异性，但它们的化学调控模式与存活率的伴随变化均较为相似。因此，化学可塑性或许是决定物种气候分布范围及其在气候变化下存活能力的关键因素。