Department of Zoology & Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa.
Department of Zoology & Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, Pretoria, South Africa.
J Insect Physiol. 2018 May-Jun;107:302-308. doi: 10.1016/j.jinsphys.2017.12.008. Epub 2017 Dec 26.
Pollen, the main protein source for honey bees, is mixed with regurgitated nectar or honey during collection and then stored as 'bee bread' before its consumption, mainly by young nurse workers. It has been suggested that storage of pollen improves its nutritional value and digestibility, but there is little evidence for such changes. We fed two fresh pollen types of different protein content (aloe and sunflower), and two stored pollen types (sunflower and a mixed pollen), to young caged worker bees. We measured daily consumption of pollen and sucrose solution, and survival after 14 days. At day 14 we recorded ovarian activation and extraction efficiency, by counting empty pollen grains in the rectal contents. Extraction efficiency is a measure of pollen digestibility. Contrary to our predictions, bees did not consume more fresh sunflower pollen than fresh aloe pollen to compensate for the lower protein content of sunflower pollen. In addition, they did not consume less sucrose solution when fed stored pollen diets that are already enriched in sugar. Consumption of stored sunflower pollen resulted in a low protein to carbohydrate (P:C) intake. Survival and ovarian activation were higher on diets giving higher P:C intakes. Extraction efficiency was high (up to 99%) for all pollen diets, and comparison of fresh and stored sunflower pollen showed that storage did not make it easier to digest. Changes to pollen during storage do not confer obvious benefits to honey bees.
花粉是蜜蜂的主要蛋白质来源，在采集过程中与反刍的花蜜或蜂蜜混合，然后作为“蜂粮”储存，主要由年轻的护理工蜂食用。有人认为，花粉的储存可以提高其营养价值和消化率，但几乎没有证据表明会发生这种变化。我们给年轻的笼养工蜂喂食了两种不同蛋白质含量的新鲜花粉（芦荟和向日葵）和两种储存花粉（向日葵和混合花粉）。我们测量了它们每天消耗花粉和蔗糖溶液的情况，以及 14 天后的存活率。在第 14 天，我们通过计数直肠内容物中排空的花粉粒来记录卵巢激活和提取效率。提取效率是衡量花粉消化率的一个指标。与我们的预测相反，蜜蜂并没有为了弥补向日葵花粉蛋白质含量较低而更多地消耗新鲜向日葵花粉，也没有在喂食已经富含糖分的储存花粉饮食时消耗更少的蔗糖溶液。食用储存的向日葵花粉导致低蛋白与碳水化合物（P:C）的摄入。给予更高 P:C 摄入量的饮食会提高存活率和卵巢激活率。对于所有花粉饮食，提取效率都很高（高达 99%），并且新鲜和储存的向日葵花粉的比较表明，储存并没有使花粉更容易消化。花粉在储存过程中的变化并没有给蜜蜂带来明显的好处。
