An issue you may have encountered as a beekeeper is the presence of laying worker bees. A worker bee can only lay drones, and therefore she cannot maintain a healthy and productive colony dynamic. Read this week’s blog to learn more about how the issue of laying workers results, how to identify the presence of laying workers and what management steps a beekeeper can take to correct the issue.

How to Identify and Manage the Issue of Laying Workers

After a colony loses its queen, and if it is unable to raise a new queen due to limited resources available (i.e. no eggs or larvae less than three days old), there is a possibility that worker bees will start to lay unfertilized eggs. Given that a laying worker bee can only lay unfertilized (male/drone) eggs the population dynamic of the colony will start to shift from worker bees to an abnormally high drone population, which is not sustainable long-term given that worker bees carry out essential colony tasks.

When a queen is present within a colony her pheromones suppress the development of ovaries in worker bees, which makes her the only reproductive female of the colony¹. Once a colony is queenless, the concentration of existing queen pheromones will gradually decrease and eventually the ovaries of worker bees have the potential to mature¹. In order for the eggs in the ovaries of workers to mature worker bees must be fed royal jelly¹. Although capable of laying eggs, workers lack the capability and anatomy to mate, which means they can only lay unfertilized eggs^1,2.

Over the past few decades there has been some research conducted on the physiology of laying workers, and how this group of bees differs from queens and non-laying workers. Researchers have found that there is greater variation in the size of eggs laid by worker bees compared to queens, with a coefficient of variance for egg length being 3.5 times higher in laying workers³. On average, it was found that eggs from queens were longer (1.620 mm), but narrower (0.368 mm) than eggs from laying workers (1.579 mm and 0.378 mm)³. In one study the development of the hypopharyngeal gland (HPG) and hemolymph vitellogenin titers was examined in laying workers to assess if their physiology was more similar to nurse bees or forger bees⁴. The researchers discovered that laying workers have physiology more similar to nurse bees compared to forger bees indicating that workers are more likely to have ovaries mature in a queenless colony earlier on in their lifespan⁴.

Generally, a colony will be queenless for approximately 21 days before a laying worker exists within the colony¹. There are a few key indicators of laying workers. To start, laying workers often lay multiple eggs per cell, and they are usually on the sides of the cell rather than the bottom of the cell². This is the result of workers having a shorter abdomen compared to a queen who can properly lay eggs at the base of the cell². Other key indicators of laying workers include a spotty brood pattern and an abnormally high percentage of drones and drone brood compared to workers².

Multiple eggs laid on sides of brood cells is a key sign of laying worker bees (© S. Camazine²).

It is difficult to locate and remove a laying worker as she is similar in appearance to other workers, and there can be many laying worker per colony, therefore, the management of this issue is not straightforward². The requeening of a colony that has laying workers is not usually successful². Frequently the colony will reject the introduced queen or queen cell if a laying worker is present^1,2.

Unfortunately, disassembling a colony is the best way to address the issue of a laying worker. If the colony shows no signs of disease, all the bees from the colony should be shaken onto the ground in the apiary, remove their hive, and the bees will drift to other colonies². There are some other suggested approaches to managing the issue, but they are not guaranteed to be successful.

The best way to prevent a laying worker is to recognize when a colony has become queenless as soon as possible, and either ensure the colony has the proper resources to raise their own queen or provide the colony with a new queen. Beekeepers should inspect colonies regularly which will help them to identify multiple queen problems early on.

References

1. Sammataro, D., and Avitabile, A. 2021. A beekeeper’s handbook: fifth edition. Cornell University Press.
2. Pernal, S. F., and Clay, H., 2013. Honey bee diseases and pests, 3rd Edition. Canadian Association Professional Apiarists, Beaverlodge, AB, Canada 68 pp.
3. Woyke, J., 1994. Comparison of the size of eggs from Apis mellifera L queens and laying workers. Apidologie, 25(2), pp.179-187.
4. Nakaoka, T., Takeuchi, H. and Kubo, T., 2008. Laying workers in queenless honeybee (Apis mellifera L.) colonies have physiological states similar to that of nurse bees but opposite that of foragers. Journal of Insect Physiology, 54(5), pp.806-812.