Queen Excluder

As the name suggests, a queen excluder’s primary purpose is to exclude the queen from entering or exiting a part of the hive. This could be used for breeding or separating the queen from the supers(where the honey is stored).

Some use the term ‘honey excluder” to refer to the queen excluder. It’s not a popular option with most commercial operations, even though they come in most beginning beekeeping kits.

It’s important to know that not all ‘bee equipment’ should be used; the queen excluder, for many purposes, falls into this category.

“The queen excluder is probably the most misunderstood and abused piece of bee equipment in use.”
Dewey M. Caron(Honey Bee Biology: page 243)

So, it mainly depends on your management practice. If you are running two deeps or three medium brood chambers throughout the year, a queen excluder is not needed. However, if you are running a single brood management system (like we are), queen excluders are required when honey supers are on.

In most cases, if you are not sure what they are used for, you should probably not be using them. They are primarily used in breeding operations and single brood management systems. It’s important to note that both queens and drones will not be able to pass through the queen excluder. If they do pass through, your queen excluder has a crack in it, or the metal is bent. So be careful with prying them off with your hive tool.

Like most of our articles, we try to look at not opinion or preference but look at the data and science if it’s available and make educated decisions based on that data. Using a queen excluder is no different. The problem is, that there is not much research that has been done on the effects of queen excluders, but we did find two research articles that touched on the use of queen excluders.

One study was done in December 2013 titled “Queen excluders enhance honey production in African honey bees, Apis mellifera, by limiting brood rearing during peak nectar flow“.

It had this to say:

“The average amount of honey obtained from the control group
colonies was significantly lower than from colonies with queen excluders…”

This research project had a small sample size of 12 colonies, half had queen excluders, and the other half did not. The results showed significantly lower brood and significantly higher honey yields for the colonies that had queen excluders, and for the colonies that did not have a queen excluder, the reverse was true. Higher brood populations and lower honey production.

Now, this study was conducted on A. m. scutellata (African Honey Bee) instead of the more popular A. m. ligustica (Italian Honey Bee) – but they are both part of the same species Apis Mellifera, so a comparison is appropriate. The brood production, though, is much different for both species, and the A.m. scutellata has about 50% more brood than A.m lugustica.

I thought the final results were interesting as the article mentions: “The negative and weak correlation detected between the brood population and honey yield at honey harvest indicates that the existence of a large
brood population at peak honey flow has no positive effect on the
honey yields of the colonies. This result is consistent with the findings
of Szabo and Lefkovitch (1989), who reported an absence of a significant correlation between honey production and brood populations reared
late during a peak honey flow period. Moreover, Nolan (1925) stated
that the quantity of nectar gathered by a colony depends not only on
the total number of bees in the colony during a honey flow but also
on the relative number of nectar foragers.”

I believe this to be true no matter what the subspecies of Apis Mellifera. Larger Honey bee populations do not mean greater honey yields. This is why a single brood management system can yield high honey loads. As this test showed approximately 25% greater honey yields with lower brood populations using a queen excluder.

The article’s final thought was compelling:

“Based on the findings of this study, it is evident that the use of
queen excluders may improve the honey yields of colonies that show
strong and continuous brood-rearing tendencies, and this indicate that
the amount of honey that can be saved from larval consumption due
to reducing brood-rearing activities during peak honey flow periods is
significant. Therefore, the partial limiting of queen’s egg laying using
queen excluders for short periods (during peak honey flow) would
improve the honey yields of honey bee colonies by maintaining a
balance in resource allocation between brood rearing and honey storage.
However, if the queen excluder is inserted before the colonies have
attained a sufficient work force, it may affect the honey yield; similarly,
if the insertion is delayed to near the end of the honey flow, it is
unlikely to contribute the honey yield of the colony. Careful determination
of the appropriate timing for inserting queen excluders, based on the
brood populations and the flowering patterns in a given area, is of
paramount importance.”

So balance is needed, and good management practice is required if you are using a queen excluder.

The only other article I could find that did some research on the subject was from Bee Informed Partnership titled “Beekeeping Equipment: Excluders!“.

In 2014 they published an article that did a small test using queen excluders on 40 hives and expressed a correlation to swarming for a hive that had a queen excluder on them the whole time.

Of course, in reading the article, it seems as though the writer, who prefers using queen excluders, was frazzled when the queen started laying in the supers, and then quickly put the queen excluders back on. The results of a correlation to higher swarming tendencies with hives that did not have queen excluders seem to be due to delayed management practices. But, logically, one may conclude that swarming could be higher when excluders are added. This is why a beekeeper would need to adjust their management practice to accommodate a queen excluder.

As a final thought of queen excluders, it is important to understand that they have a limited timetable and are not kept on throughout the whole year. Only during breeding practices – with understood biological consequences, and only when supers are on for the purpose of gathering excess resources from a honey flow – recommended only when running single brood chambers.

Whether you use one or not is not the point of this article, but rather to provide some information for the management of your honey bees. As with any piece of bee equipment, understanding the when, why, and how is vital for success.

Happy beekeeping.