Larval nutrition impacts survival to adulthood, body size, and the allometric scaling of metabolic rate in adult honeybees

Resting metabolic rate (RMR) is a fundamental physiological measure linked to numerous aspects of organismal function, including lifespan. Although dietary restriction in insects during larval growth/development affects adult RMR, the impact of larval diet quality on adult RMR has not been studied. Using in vitro rearing to control larval diet quality, we determined the effect of dietary protein and carbohydrate on honeybee survival-to-adulthood, time-to-eclosion, body mass/size and adult RMR. High carbohydrate larval diets increased survival-to-adulthood and time-to-eclosion compared to both low carbohydrate and high protein diets. Upon emergence, bees reared on the high protein diet were smaller and lighter than those reared on other diets, whilst those raised on the high carbohydrate diet varied more in body mass. Newly emerged adult bees' reared on the high carbohydrate diet showed a significantly steeper increase in allometric scaling of RMR compared to those reared on other diets. This suggests that diet quality influences survival-to-adulthood, time-to-eclosion, and the allometric scaling of RMR. Given that agricultural intensification and increasing urbanisation have led to a decrease in both forage availability and dietary diversity for bees, our results are critical to improving understanding of the impacts of poor developmental nutrition on bee growth/development and physiology.

静息代谢率（Resting metabolic rate, RMR）是与生物体诸多机能（包括寿命）密切相关的核心生理指标。尽管昆虫幼虫期生长发育过程中的饮食限制会影响成虫的静息代谢率，但目前尚无关于幼虫期饮食质量对成虫静息代谢率影响的相关研究。本研究通过体外饲养（in vitro rearing）手段严格控制幼虫饮食质量，探究了膳食蛋白质与碳水化合物对蜜蜂羽化至成虫的存活率、羽化耗时、体质量与体型以及成虫静息代谢率的影响。研究结果显示：相较于低碳水与高蛋白饮食组，高碳水幼虫饮食可提升蜜蜂羽化至成虫的存活率并延长羽化耗时；羽化初期，高蛋白饮食组的蜜蜂体型更小、体质量更轻，而高碳水饮食组的蜜蜂体质量变异程度更高；与其他饮食组相比，高碳水饮食组培育的新羽化成虫的静息代谢率异速生长标度斜率显著更陡。本研究表明，饮食质量会显著影响蜜蜂的羽化存活率、羽化耗时以及静息代谢率的异速生长标度。鉴于农业集约化与城市化进程导致蜜蜂的蜜源可获得性与饮食多样性持续下降，本研究结果对于深化人们对发育阶段营养不良如何影响蜜蜂生长发育与生理机能的理解具有至关重要的意义。