Woodard S Hollis, Duennes Michelle A, Watrous Kristal M, Jha Shalene
Department of Entomology, University of California, Riverside, Riverside, CA, USA.
Department of Biology, Saint Vincent College, Latrobe, PA, USA.
Conserv Physiol. 2019 Aug 15;7(1):coz048. doi: 10.1093/conphys/coz048. eCollection 2019.
Many insects sequester nutrients during developmentally programmed periods, which they metabolize during subsequent life history stages. During these periods, failure to store adequate nutrients can have persistent effects on fitness. Here, we examined a critical but under-studied nutrient storage period in queen bumble bees: the first days of adult life, which are followed by a diapause period typically coinciding with winter. We experimentally manipulated availability of pollen (the primary dietary source of lipids and protein) and the sugar concentration of artificial nectar (the primary source of carbohydrates) for laboratory-reared queens during this period and examined three nutritional phenomena: (i) diet impacts on nutritional status, (ii) the timescale upon which nutrient sequestration occurs and (iii) the fitness consequences of nutrient sequestration, specifically related to survival across the life cycle. We found evidence that pollen and nectar starvation negatively impact lipid storage, whereas nectar sugar concentration impacts stored carbohydrates. The majority of nutrients were stored during the first ~ 3 days of adult life. Nutrients derived from pollen during this period appear to be more critical for surviving earlier life stages, whereas nutrients sequestered from nectar become more important for surviving the diapause and post-diapause periods. Negative impacts of a poor diet during early life persisted in our experiment, even when pollen and a relatively high (50%) nectar sugar concentration were provided post-diapause. Based on these findings, we posit that the nutritional environment during the early adult life of queens has both immediate and persistent impacts on fitness. These findings underscore the importance of examining effects of stage-specific nutritional limitations on physiology and life history traits in this social insect group. Moreover, the findings may shed light on how declining food resources are contributing to the decline of wild bumble bee populations.
许多昆虫在发育程序设定的时期内储存营养物质，并在随后的生命史阶段进行代谢。在这些时期，未能储存足够的营养物质可能会对适应性产生持久影响。在这里，我们研究了蜂王熊蜂一个关键但研究不足的营养储存期：成年后的头几天，随后是通常与冬季重合的滞育期。在此期间，我们通过实验操纵了实验室饲养的蜂王的花粉（脂质和蛋白质的主要饮食来源）供应和人工花蜜（碳水化合物的主要来源）的糖浓度，并研究了三种营养现象：（i）饮食对营养状况的影响，（ii）营养物质储存发生的时间尺度，以及（iii）营养物质储存的适应性后果，特别是与整个生命周期的生存相关的后果。我们发现有证据表明，花粉和花蜜饥饿会对脂质储存产生负面影响，而花蜜糖浓度会影响储存的碳水化合物。大多数营养物质是在成年后的头约3天内储存的。在此期间从花粉中获取的营养物质似乎对生命早期阶段的生存更为关键，而从花蜜中储存的营养物质对滞育期和滞育后期的生存变得更为重要。即使在滞育后提供花粉和相对较高（50%）的花蜜糖浓度，早期生活中不良饮食的负面影响在我们的实验中仍然存在。基于这些发现，我们认为蜂王成年早期的营养环境对适应性既有即时影响也有持久影响。这些发现强调了研究特定阶段营养限制对这种社会性昆虫群体的生理和生活史特征的影响的重要性。此外，这些发现可能有助于揭示食物资源减少如何导致野生熊蜂种群数量下降。
