American Beekeeping Journal – August, 1985, pg 564-567
by G. W. HAYES, JR.
Dadant & Sons, Inc.
A few years ago while associated with OSU/ATI, I was able to start research on a question that has always sparked interest for beekeepers. I have not been able to finish the preliminary study as yet, but thought that I would share the first thought provoking data that was gathered with the readers of the American Bee Journal. This paper will be presented at the upcoming XXXth International Beekeeping Congress in Nagoya, Japan.
When you mention the words queen excluder at a gathering of beekeepers you have just set the stage for a minimum of 60 minutes of discussion. Every beekeeper has their own opinion of the use or nonuse of queen excluders: when to install them or not, whether a queen excluder not only excludes the queen from the honey supers, but perhaps the honey itself from the honey supers.
As far as can be determined, no one has published data on a controlled experiment to attempt to answer the Queen Excluder/Honey Excluder question. On a small scale I have attempted to begin this research with some interesting preliminary findings.
On the last week of March 1983 16 palletized colonies that had just arrived from overwintering in Florida were moved into one of the selected outyards maintained at ATI. All colonies at this time consisted of four hives per pallet in two deep brood chambers, standard bottom entrances and migratory tops.
In order to test the hypothesis that a queen excluder is also a honey excluder, changes were made to some of the colonies. Of the 16 colonies, six were designated control colonies and were to retain the standard bottom entrance, no queen excluder was to be installed, and they would be supered as necessary. Five colonies were designated to retain the standard bottom entrance, but were to be fitted with a standard wire queen excluder above the second deep and supered as necessary. Five colonies were finally designated to have their bottom entrance closed completely, a drone escape provided, a standard queen excluder was to be fitted above the second deep with an entrance spacer above the queen excluder, then supered as necessary. (See Diagram A)
All colonies were equalized as best as possible for brood. Excluders and upper entrances were installed.
The colonies were now left for approximately three weeks to adjust to their new surroundings and to allow the brood used in equalization to emerge before the first brood chamber measurements were taken. The object of taking measurements for approximate square inches of brood visible (open and capped) was to determine in later measurements if the placement or location of entrances and queen excluders affected brood rearing and finally forager population as it correlated to honey stored.
Measurements of the amount of brood were done by utilizing a clear sheet of plastic marked off in one inch square grids. The sheet was laid on one side, then the other, of a brood frame and the appropriate grids were simply counted. This was done three times during the course of the experiment at approximately the beginning, middle and end of the season.
On May 13, 1983 the first brood measurements yielded an average of approximately 170 sq. in. of brood for the Control colonies, approximately 156 sq. in. of brood were measured in the Bottom Entrance/Queen Excluder colonies, and approximately 143 sq. in. of brood for the Upper Entrance/Queen Excluder colonies. Brood was mainly confined to the middle frames of the first or second brood chamber. At this time a 6-5/8 super with drawn comb was arbitrarily added to all colonies to start the season.
Colonies were checked every two weeks if possible in anticipation of the beginning nectar flow and supered as necessary.
The next brood measurement took place on July 7, 1983 in the midst of our white clover bloom. Foragers were bringing in significant quantities of nectar at this time. Brood measurements for the Control colonies now averaged approximately 738 sq. in., for the Bottom Entrance/Queen Excluder colonies the average was now approximately 434 sq. in. and approximately 806 sq. in. for the Upper Entrance/Queen Excluder colonies.
A trend was beginning to take shape with this second brood measurement. In the Bottom Entrance/Queen Excluder colonies the field force seemed to be reluctant to travel through the queen excluder to deposit their nectar load in the honey super. Instead the incoming field force was depositing a majority of their nectar in any available open cell in the two brood chambers. This, in turn, limited the amount of area available to the queen to lay with a resultant loss of population. The brood chambers were “honey bound.” This condition was not found in either the control colonies or The Upper Entrance/Queen Excluder colonies. In fact the Upper Entrance/Queen Excluder colonies had an edge in the amount of brood because of a reverse condition. The brood chambers had good supplies of pollen, but only a very thin band of honey or nectar. The incoming foragers seemed to be reluctant to travel through the excluder with a full load of nectar into the brood chamber, choosing instead to place it directly into the honey supers. Only a minimum amount was brought below, apparently only enough for brood rearing and little surplus.
At this time skunk predation was first noticed. It was most apparent in colonies with bottom entrances, the upper entrance colonies were virtually ignored. As most beekeepers who have had skunk problems know, the small furry animals make nocturnal visits to the hives. The skunk stations itself in front of the hive and scratches vigorously at the entrance with its front paws. The bees respond to the disturbance at the entrance by marching out of the hive. The skunk simply eats them as they appear, being little bothered by stings. The upper entrances made the skunks normal feeding pattern (such as at standard hives) almost impossible because of the entrance height problem posed to the skunk.
On Sept. 3, 1983 the last brood chamber measurement was taken. The Control colonies contained an average of approximately 724 sq. in. of brood, the Bottom Entrance/Queen Excluder contained approximately 386 sq. in. of brood and the Upper Entrance/Queen Excluder colonies approximately 796 sq. in. As can be seen, all of the colonies dropped somewhat in the amount of brood. These drops were not very significant except in the Bottom Entrance/Queen Excluder colonies. At this time skunks had killed outright one Bottom Entrance/Queen Excluder colony and two were very weak. The Control colonies were also being fed upon at night by skunks, but were not as damaged as the Bottom Entrance/Queen Excluder colonies. I am assuming that because of more brood rearing area in the Control Colonies and the resultant larger populations, that the feeding by the skunks was not as debilitating as on the Bottom Entrance/Queen Excluder colonies, the latter having smaller populations as a result of “honey boundness” and less brood rearing area.
On September 6, 1983 the honey supers were removed and weighed for each colony. The approximate amount of honey was determined by subtracting the weight of an empty super with drawn comb from the weight of a super removed from each colony. The average honey stored in the honey supers is as follows. Control colonies 49.0 pounds per colony, Upper Entrance/Queen Excluder colonies 47.4 pounds per colony and Bottom Entrance/Queen Excluder colonies 14.2 pounds per colony.
These figures were derived by adding all poundages of approximate net honey stored per colony type and then dividing by the number of colonies of that type; irrespective of the fact that some colonies stored no surplus because of certain unforeseen variables, (skunks, queen disappearance). This next group of averages represents the average weights of honey stored per colony type with the colonies not storing a surplus (the 0’s) not used in the calculation at all. Control Colonies averaged 58.8 pounds of honey per colony, the Upper Entrance/Queen Excluder colonies averaged 59.25 pounds per colony of stored honey and the Bottom Entrance/Queen Excluder colonies 35.5 pounds of stored honey per colony. (See Table 1)
These results are quite dramatic in this experiment. It appears from this limited test that queen excluders may well indeed also be honey excluders. From this data the use of queen excluders should be highly coordinated with an appropriate upper entrance. This may well help to maintain the queen in a designated brood area away from honey supers and perhaps maximize the amount of usable, extractable honey.
UPPER ENTRANCE COLONIES
As this experiment was proceeding I could tell that the upper entrance colonies were doing well. So, as a side note I would like to expand on the upper entrance theme based on observations made in the Queen Excluder experiment.
I am sure that many beekeepers have noticed that if an upper entrance auger hole is left open in summer or if there is a crack or gap between supers or perhaps a warped top, that a high percentage of bees prefer this entrance/exit. It was found that a large percentage of all colonies in the wild like to maintain an entrance above the brood chamber. One reason is because the very important brood chamber temperature can be maintained more efficiently than when exposed directly to drafts, breezes etc. from bottom openings. The slatted rack has often been proposed as a remedy to this problem in years past. But by just relocating the entrance to its more natural position, the expense and time needed to make, install and remove the slatted rack is eliminated. In fact it is now my personal opinion that the only reason that we have hives with bottom entrances and a little front porch on the bottom board is because the early designers of bee equipment had front porches and doors on the first floor of their houses so “by-George the bees will too!” If one has ever taken out a brood frame from the bottom brood chamber and closely looked at the brood pattern, it will be seen that this pattern is many times shifted towards the back of the hive and away from the entrance. In the Upper Entrance/Queen Excluder colonies this was not found at all. In these colonies it appeared that the sole restraint to the queen’s egg laying was her ability to lay only so many eggs per day.
Another observation was that on very warm humid days the number of bees hanging outside at the entrance was much less noticeable than that of the bottom entrance colonies. Because of the upper entrance, the brood chamber was being ventilated by natural convection. The warm moist air was rising up and out of the entrance in a natural cycle as outside air entered.
As noted, there was a skunk problem that affected the results in the Queen Excluder experiment. The Upper Entrance colonies were left alone by the skunks, while the Bottom Entrance hives were fed on, heavily at times.
I tried to mow this yard on a regular basis to control weed height as it affected the flight of the foragers. Weed height was not a problem with the Upper Entrance colonies as was the case with the Bottom Entrance colonies. Any beekeeper who has outyards and has ever had to mow or clip the weeds away from bottom hive entrances knows this is a problem area. Many trips to the outyards, and stings on the hands may be eliminated with the upper entrance.
I was much impressed with the advantages of the Upper Entrance colonies as observed in the Queen Excluder experiment. We as beekeepers are constantly barraged with information about how beneficial ventilation and moisture removal is in over-wintered colonies. The Upper Entrance is always suggested as a method to accomplish this in winter and in very warm humid conditions during the summer. There have been many, many articles and whole sections of books written on the upper entrance theme. The Rev. Langstroth’s original book devoted a whole section to the benefits of the upper entrance and some of the most well known researchers in apiculture have also noted the benefits of the upper entrance. Perhaps we as beekeepers should be more flexible, and look more closely at the Upper Entrance as a more efficient year-round option.
Morse, R. A. 1983. Queen Excluders, Gleanings in Bee Culture.
Root A. I. 1980. ABC/XYZ of Bee Culture page 235, 683.
Townley, E. 1843. A practical treatise on humanity to honey bees. NY. Printed by William S. Darr.
Jaycox, E. R. 1977. Journal Bees and Honey.
Savin. 1970. Vol. 23 Velikost Cesna.
Gojmerac, W. L. 1980. Bees, Beekeeping, Honey and Pollination p. 92.
Free, J. B. and Williams, I. H. 1976. Applied Animal Ethology p. 141-154.