Abstract

Bumble bees are important pollinators in natural environments and agricultural farmlands, and they are in particular adapted to harsh environments like high mountain habitats. In these environments, animals are exposed to low temperature and face the risk of desiccation. The Eastern Himalayas are one of the recognized biodiversity hotspots worldwide. The area covers subtropical rainforest with warm temperature and high precipitation as well as high mountain ranges with peaks reaching up to 7,000 m, shaping a diverse floral and faunal community at the different elevational zones. To identify possible adaptation strategies, we investigated the cuticular hydrocarbon profiles of four bumble bee species occurring at different elevational ranges in Arunachal Pradesh, the northeastern most state in India. At 17 locations along an elevational gradient, we collected workers of two species from lower elevations (B. albopleuralis and B. breviceps; ~ 100 m − 3,000 m asl) and two species from higher elevations (B. prshewalskyi and B. mirus; ~ 2,800 m − 4,500 m asl). The CHC profiles of all four species showed a significant degree of variation in the composition of hydrocarbons, indicating species specificity. We also found clear correlation with elevation. The weighted mean chain length of the hydrocarbons significantly differed between the low and high elevation species, and the proportion of saturated hydrocarbons in CHC profiles significantly increased with the elevational range of the bumble bee species. Our results indicate that bumble bees living at high elevations reduce the risk of water loss by adapting their CHC composition on their cuticle, a phenomenon that has also been found in other insects like ants and fruit flies.

中文翻译：

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喜马拉雅熊蜂（膜翅目：Bombus Latreille）的表皮碳氢化合物剖面具有物种特异性并显示出海拔变化

摘要

熊蜂是自然环境和农田中重要的传粉者，它们特别适应高山栖息地等恶劣环境。在这些环境中，动物暴露在低温下并面临干燥的风险。喜马拉雅山脉东部是世界公认的生物多样性热点地区之一。区内既有气温温暖、降水量多的亚热带雨林，也有海拔7000米的高山，不同海拔地区形成了多样化的动植物群落。为了确定可能的适应策略，我们研究了印度最东北部的阿鲁纳恰尔邦不同海拔范围内四种熊蜂的表皮碳氢化合物分布。在沿海拔梯度的 17 个地点，我们收集了来自较低海拔地区的两种工蚁（B. albopleuralis和B. breviceps； ~ 100 m − 3,000 m asl）和来自较高海拔地区的两种工蚁（B. prshewalskyi和B. mirus；~ 2,800 m – 4,500 m（标准高度））。所有四个物种的 CHC 谱显示碳氢化合物的组成存在显着程度的变化，表明物种特异性。我们还发现与海拔的明显相关性。低海拔物种和高海拔物种的烃类加权平均链长存在显着差异，并且CHC剖面中饱和烃的比例随着熊蜂物种海拔范围的增加而显着增加。我们的研究结果表明，生活在高海拔地区的熊蜂通过调整其角质层上的 CHC 成分来降低水分流失的风险，这种现象在蚂蚁和果蝇等其他昆虫中也发现了。