Larval starvation affects metabolic physiology and behaviors of adult honeybees

Larval nutrition in many solitary insects affects adult body size, fecundity and lifespan. In honeybees, malnutrition is largely responsible for colony losses. Although carbonization by workers is applied to malnourished larvae at early stage, the elder malnourished larvae are able to develop to adults. Here, we performed the starvation on honeybee larvae at the 5^th instar stage to investigate the effects of larval nutrition on adult bees. We found newly emerged bees with the early starvation were smaller than controls, had smaller ovaries, and were less sensitive to sugar. In addition, these bees had higher glucose and trehalose titer in their hemolymph, had less protein content, and tended to reduce lipid store in the fat body. By looking at the gene expression and endocrine hormone in these treated bees, we found juvenile hormone (JH) titer was increased in the hemolymph and tyramine receptor (TYR) expression was decreased in the fat body. Overall, our study demonstrates that larval nutrition affects honeybee morphological traits and energy metabolism of adult bees, which are important for honeybee health and foraging behaviors. Our data also suggest that JH and tyramine may be involved in the metabolic regulation in the bees with the early starvation.