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 the nutritional composition of larval diets (i.e. 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 with 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 with those reared on other diets. This suggests that the nutritional composition of larval diets 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.