Queen bees and worker bees develop from fertilized eggs, and drone bees develop from nonfertilized eggs. Queens develop from eggs laid in downward facing queen cell cups similar to the one on the side of a top bar hive comb (photo by Melissa Bridgman). A New York Times piece, https://www.nytimes.com/2017/08/31/science/honeybees-queens.html?, describes recently published research from PLOS Genetics identifying a newly-identified mechanism involved in the development of queen bees. It has long been known that queen bee development is associated with diet. Worker bees feed developing queen bees and worker bees a different diet even though they both develop from the same fertilized eggs. The larvae of both queens and workers are fed an enriched food, royal jelly, in the first day of larval development. Worker larvae are then fed secretions workers produce from “bee bread,” a food consisting of fermenting pollen and honey. Queen larvae, however, continue to receive royal jelly through their larval development and throughout their life.
The new research finds that caste development, the differentiation of queens, which have a complete reproductive system, from workers, that are sterile, uses plant-based small molecules called microRNA. The study’s co-author, Dr. Chen-Yu Zhang explains, “The royal jelly and plant microRNA work together to affect caste formation.” It now appears that the plant-based molecules suppress the workers’ ovary development. This research expands our understanding of queen bee caste differentiation. It also reflects the interdependence of plants and honey bees. Flowering plants and bees have been co-evolving for the past 100 million years. Plants and bees share microRNA, a plant substance that affects bee development and a bee substance that is important in the development of certain flowers. Dr. Zhang explains that microRNA from bees can make flowers larger and more colorful. The authors relate that these microRNA molecules affect species in different kingdoms, such as plants and insects or plants and humans. Other experts reacting to the report expect that microRNA will emerge as a major area of research in human medicine.--Richard