Monday September 18, 2017 Q&A

What determines which honeybees will be worker bees?


1 The males: those with small abdomens can father only worker bees

2 Their food, which causes some parts of their body to atrophy

3 The queen bee decides which will be the worker bees

Correct answer: their food, as a diet of honey and pollen causes some parts of their body to atrophy.

The caste that a particular honeybee will belong to – queen bee or worker bee – is determined not by dynasty, or merit, or even genetics. All honeybees have the same DNA; their rank is determined mainly by their diet. In the first three days of life, all bee larvae feed on royal jelly – a substance rich in protein and lipids. Then only those born in large honeycomb cells continue to feed on royal jelly, while the others subsist on a more rudimentary diet of honey and pollen in a mixture called “beebread.” And this makes a big difference: the former grow into large, fertile queens, while the latter become small, sterile workers.

Scientists have been studying royal jelly, which is produced by juvenile worker bees, for several years to identify which of its compounds boosts the growth of the young queens. In 2011, a team of Japanese scientists discovered a microbiological process that could have something to do with it. A protein called royalactin appears to play a major role in the development of queens’ bodies and ovaries by activating the signaling pathway of a specific gene.

However, a team of Chinese researchers recently found another process that can explain the caste differentiation. Their work, published in the August issue of PLOS Genetics, shows that the honey-pollen mixture that young worker bees feed on contains a molecule with an epigenetic effect on honeybees. This molecule, a microRNA found in the plants from which the pollen is taken, causes parts of bees’ bodies to atrophy, making them sterile and shortening their lifespan.

These two studies show the pivotal role that a bee’s diet plays on its caste, as well as the evolutionary link between plants and animals. The same microRNA that stunts worker bees’ development plays a role in the formation of certain flowers – those with more of the molecule become larger and more colorful. That attracts bees, thereby helping the plant spread its seeds. The scientists believe this is an area for further research that could possibly provide some insight into the mysterious death of hordes of bees in the past decade.

Do queen bees really live happier lives than their worker counterparts? Not necessarily. Their fertile bodies mean they lay some 200 eggs a day, confined to their beehives for their entire lives. And since they cannot feed themselves, they are dependent on their worker bees for nourishment. If the workers believe the queen has failed at her reproductive duties, they will stop supplying her with royal jelly and select a new queen – leaving the former queen to starve to death, abandoned by her colony.

Fore more informations:

Article in PLOS genetics (august 2017)

Article in Nature (may 2011)