Nutrition affects longevity and gene expression in honey bee (Apis mellifera) workers

Abstract

Nutrition is a major factor affecting animal health, resistance to disease, and survival. In honey bees (Apis mellifera), nectar or honey (carbohydrates) is the energy source, while pollen, which is the sole dietary source of protein, is essential for both larval and adult development. Royal jelly (RJ), a secretion from workers with high protein content, plays a critical role in which queens are fed throughout their lives, is responsible for switching the worker phenotype into the queen one. The role of RJ in extending the lifespan of caged workers is not clear. In this study, we determined longevity of caged workers fed with different diets (carbohydrate only, pollen, and pollen+ RJ) and also expression of six genes in these bees. We found that workers fed with pollen and royal jelly together (P+ RJ+) showed the best survival, followed by workers fed with pollen only (P + RJ−), and workers fed with neither pollen nor RJ (P− RJ−) had the shortest life. Pollen only (P + RJ−) and royal jelly together (P+ RJ+) significantly affected four of the six genes studied. While pollen and royal jelly together (P+ RJ+) only affected the vitellogenin gene compared to pollen only (P+ RJ−). These results demonstrate that pollen and RJ extended worker longevity, suggesting that they may improve the nutritional conditions of bees or contain health and longevity-promoting factors. Further analysis of the lifespan-extending genes may broaden our understanding of gene network involved in the regulation of longevity.