Royal jelly: one of several factors involved in queen development

The main environmental determinants of caste development in bees arise from larval nutrition: royal jelly stimulates the differentiation of larvae into queens, whereas bee bread leads to the development of worker bees. However, these determinants have not yet been fully characterized.

The authors of the article report that plant RNAs, in particular miRNAs, which are more concentrated in pollen and bee bread than in royal jelly, delay development and reduce the body and ovarian size of larvae, thereby preventing differentiation into queens and inducing the development of worker bees. Mechanistic studies reveal that amTOR, a gene that stimulates caste differentiation, is a direct target of miR162a. Interestingly, the same effect is also observed in non-social drosophilid flies. When such plant RNAs and miRNAs are administered to Drosophila larvae, they cause an extension of larval development time, a reduction in insect weight and length, as well as decreased ovarian size and fertility. This study identifies a previously uncharacterized function of plant miRNAs that fine-tunes caste development in bees, offering hypotheses to better understand the interaction and co-evolution between the animal and plant kingdoms.