Data from: The geometric framework for nutrition reveals interactions between protein and carbohydrate during larval growth in honey bees

In holometabolous insects, larval nutrition affects adult body size, a life history trait with a profound influence on performance and fitness. Individual nutritional components of larval diets are often complex and may interact with one another, necessitating the use of a geometric framework for elucidating nutritional effects. In the honey bee, Apis mellifera, nurse bees provision food to developing larvae, directly moderating growth rates and caste development. However, the eusocial nature of honey bees makes nutritional studies challenging, because diet components cannot be systematically manipulated in the hive. Using in vitro rearing, we investigated the roles and interactions between carbohydrate and protein content on larval survival, growth, and development in A. mellifera. We applied a geometric framework to determine how these two nutritional components interact across nine artificial diets. Honey bees successfully completed larval development under a wide range of protein and carbohydrate contents, with the medium protein (∼5%) diet having the highest survival. Protein and carbohydrate both had significant and non-linear effects on growth rate, with the highest growth rates observed on a medium-protein, low-carbohydrate diet. Diet composition did not have a statistically significant effect on development time. These results confirm previous findings that protein and carbohydrate content affect the growth of A. mellifera larvae. However, this study identified an interaction between carbohydrate and protein content that indicates a low-protein, high-carb diet has a negative effect on larval growth and survival. These results imply that worker recruitment in the hive would decline under low protein conditions, even when nectar abundance or honey stores are sufficient.

在全变态昆虫（holometabolous insects）中，幼虫营养会影响成虫体型——这是一类对个体表现与适合度（fitness）具有深远影响的生活史性状（life history trait）。幼虫日粮的单个营养组分往往结构复杂，且彼此间可能存在交互作用，因此需借助营养几何框架（geometric framework）来阐明营养效应的作用机制。在西方蜜蜂（Apis mellifera）种群中，保育蜂（nurse bees）会为发育中的幼虫提供食物，直接调控幼虫的生长速率与级型发育（caste development）。然而，西方蜜蜂的真社会性（eusocial nature）特性使得营养研究极具挑战性：在蜂箱内部无法对日粮组分开展系统性操控。本研究借助离体饲养（in vitro rearing）技术，探究了西方蜜蜂日粮中碳水化合物（carbohydrate）与蛋白质（protein）含量对幼虫存活、生长及发育的调控作用及其交互效应。我们采用营养几何框架，分析了9种人工日粮下这两种营养组分的交互作用模式。西方蜜蜂可在较宽的蛋白质与碳水化合物含量范围内顺利完成幼虫发育阶段，其中蛋白质含量约5%的中等蛋白日粮组幼虫存活率最高。蛋白质与碳水化合物均对幼虫生长速率具有显著的非线性（non-linear）效应，其中中等蛋白、低碳水化合物日粮组的生长速率达到峰值。日粮组分对幼虫发育时长无统计学显著（statistically significant）影响。本研究结果证实了此前的相关结论：蛋白质与碳水化合物含量会影响西方蜜蜂幼虫的生长发育。但本研究同时揭示了二者的交互作用：低蛋白、高碳水化合物日粮会对幼虫生长与存活产生负面影响。该结果意味着，即便花蜜储量充足或蜂蜜储备丰富，蜂群内的工蜂招募（worker recruitment）量也会在蛋白质供应不足的情况下出现下降。