Many diapausing insects undergo a nutrient storage period prior to their entry into diapause. Bumble bee queens diapause as adults in the winter preceding their spring nest initiation period. Before diapause, they sequester glycogen and lipids, which they metabolize during the overwintering period. We used RNA sequencing to examine how age and nectar diet (specifically, the concentration of sucrose in nectar) impact gene expression in the pre-overwintering bumble bee queen fat body, the "liver-like" organ in insects with broad functions related to nutrient storage and metabolism. We found that diet on its own, and in combination with age, impacts the expression of genes involved in detoxification. Age was also a strong driver of gene expression, especially at earlier ages (up to 3 days). In addition to these molecular correlates of diet and age, we also found a putative molecular signature of diapause entry or preparation in adult queens in the oldest age group (12 days) fed the most sucrose-rich diet, based on comparisons between our data set and another transcriptome data set from bumble bee queens. This transcriptomic pattern suggests that preparation for (or entry into) diapause might be in part mediated by nutritional state in bumble bee queens. Collectively, these findings show that there are molecular processes in the fat body that are responsive to sucrose levels in the diet and/or associated with age-related maturational changes. A better understanding of these processes may shed light on important aspects of bumble bee biology, such as queen responses to nutritional and other forms of stress, and the factors that regulate their entrance into diapause.

中文翻译：

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转录组分析揭示了越冬前大黄蜂皇后脂肪体内基因表达的营养和年龄相关模式。

许多具滞育性的昆虫在进入滞育之前都要经历一个养分储存期。大黄蜂蜂王在成年期开始之前的冬天成年滞育。滞育前，它们会隔离糖原和脂质，它们在越冬期间会代谢。我们使用RNA测序来检查年龄和花蜜饮食（特别是花蜜中蔗糖的浓度）如何影响越冬前大黄蜂蜂后脂肪体（与营养相关的广泛功能的昆虫中的“肝状”器官）基因表达储存和代谢。我们发现，饮食本身以及与年龄结合会影响排毒中涉及的基因的表达。年龄也是基因表达的重要驱动力，尤其是在较早的年龄（最多3天）。除了饮食和年龄的这些分子相关性外，我们还根据数据集之间的比较，发现了在最年长的年龄组（12天）中摄入最富含蔗糖的饮食的成年女王的滞育进入或滞育的推测分子特征。另一个来自大黄蜂女王的转录组数据集。这种转录组学模式表明，滞育蜂的准备（或进入滞育）可能部分由大黄蜂女王的营养状态所介导。总的来说，这些发现表明，脂肪体内存在分子过程，这些分子过程对饮食中的蔗糖水平有反应，并且/或者与年龄相关的成熟变化有关。更好地了解这些过程可能有助于了解大黄蜂生物学的重要方面，例如女王对营养和其他形式压力的反应，