Differences in the morphology, physiology and gene expression of honey bee queens and workers reared in vitro versus in situ

Abstract

The effect of larval nutrition on female fertility in honey bees is a focus for both scientific studies and for practical applications in beekeeping. In general, morphological traits are standards for classifying queens and workers and for evaluating their quality. In recent years, in vitro rearing techniques have been improved and used in many studies; they can produce queen-like and worker-like bees. Here, we questioned whether queens and workers reared in vitro are the same as queens and workers reared in a natural hive environment. We reared workers and queens both in vitro and naturally in beehives to test how these different environments affect metabolic physiology and candidate genes in newly emerged queens and workers. We found that sugar (glucose and trehalose) levels differed between queens and workers in both in vitro and in-hive-reared bees. The in vitro-reared bees had significantly higher levels of lipids in the abdomen. Moreover, hive reared queens had almost 20 times higher levels of vitellogenin than in vitro-reared queens, despite similar morphologies. In addition, hive-reared bees had significantly higher levels of expression of mrjp1. In conclusion, in vitro rearing produces queens and workers that differ from those reared in the hive environment at physiological and gene expression levels. This article has an associated First Person interview with the first author of the paper.

Keywords

• Honey bee queen quality
• Geometric morphometrics
• Carbohydrate metabolism
• Ovariole number
• Caste development