by William C. Roberts and Otto Mackensen
U.S.D.A., Agr. Res. Adm., Bureau of Entomology and Plant Quarantine*
(*In cooperation with the Wisconsin Agricultural Experiment Station and Louisiana State University.)
V. Production of Hybrid Queens
EVERY commercial queen producer has his own system of management. Just what system will produce the best quality queens at the most economical cost is not definitely known. Having been engaged in the breeding and testing of bees for a number of years, we have naturally tried many methods. Herewith we will describe the method that we use for producing large numbers of hybrid test queens at the Kelleys Island, Ohio, mating station. We use this method because we have found that it produces the largest proportion of good queens at the most economical cost of any method that we have used.
In testing stocks we, of course, must have environmental factors of queen rearing as nearly constant as possible and must also attempt to produce queens of the highest quality. In order to measure genetic differences we must create an environment that will permit the genetic potentialities to be expressed to their fullest extent.
We begin to prepare for queen rearing in the fall. Six months before we intend to make the first graft of queen cells we requeen every colony on the island with queens from which we desire drones the following year. Let us call these queens hybrids (1 x 2), produced by crossing inbred lines 1 and 2. Into every colony we introduce a (1 x 2) hybrid queen. Since the island is isolated and every colony has a (1 x 2) hybrid queen, we will have control of the drone population the following year. We clip all queens and mark them so that they can be identified and found easily.
All colonies must have ample populations of worker bees to winter properly and build up rapidly in the spring. They must also have enough honey properly organized for wintering plus plenty of reserve for build-up in the spring.
Our colonies are in square hive bodies. Each hive body holds 12 frames of the Dadant shallow size. We winter each colony in four hive bodies. When ready for winter, the colony has a (1 x 2) hybrid queen, a good population of young bees, 70 to 80 pounds of honey, and several frames of pollen. The bottom entrance block is placed in the entrance with a 3/4-inch opening for a lower entrance. A 1-inch auger hole in the second hive body from the top gives an upper entrance near the location of the winter cluster of bees. Colonies prepared in this manner in the fall need little, if any, attention during the winter.
About March 15 we check the colonies for queens, brood, honey, and pollen. At that time most of the cluster of bees and the brood nest should be in the top hive body. If not, we organize it so that supplemental feeding of pollen cakes can proceed in an orderly fashion. We give the colonies 1- to 1-1/2-pound pollen cakes by placing them on the top bars between the frames and the reversed inner cover. We give additional pollen cakes as needed – one every week or 10 days – until the supply of natural pollen is adequate. We usually have to feed pollen cakes until about May 10, or at the beginning of apple blossoming.
When we give the third pollen cakes to the colonies, we add a drone comb to the brood nest. The colonies get an additional drone comb with the next pollen cakes. All swarm-box and finishing colonies get two to four good drone combs, and they remain part of the brood nest throughout the season.
From the 4 to 6 frames with brood on March 15 the colonies should expand their brood nests to about 20 frames with brood on May 10. As soon as the colonies have brood in two hive bodies, we interchange the upper two bodies so that the brood nest can expand rapidly. When the brood nest expands to the three hive bodies, we interchange the top and bottom bodies around the middle hive body with brood. At about that time we are ready to begin queen rearing.
In our operations we plan to make our first graft of queen cells about May 10. To insure prompt matings it is necessary to have adult drones in the hives when the first graft of queen cells is made. To have adult drones on May 10 we must have drone eggs on April 15. Thus we give our colonies drone combs about April 10 with the third round of pollen cakes.
Drone combs are very important in our operations. We inspect them every time we work the colonies. We never allow them to be shoved outside the brood nest or to be filled with honey. We have a standing rule that when we cannot find plenty of drone eggs, larvae, pupae, and adults, we stop all work and put these good dark drone combs in the middle of the brood nests so that the queens will fill them with drone eggs. One has to run low on drones only once to find out how valuable they are in queen production.
For starting queen cells we use a modification of the swarm box. To prepare a swarm box we find the queen in the colony and set the frame she is on aside. We set the top hive body on a screen division board on top of the reversed hive cover on the ground. In this hive body we have 10 frames. At least three of the frames in the center must be one-half to two-thirds filled with open honey and pollen. The other six frames should have a little honey but should not be heavy with sealed honey. We shake the bees from 8 to 10 frames of brood into this hive body to get about four pounds of bees into this body. We place the inner cover immediately on this hive body to prevent too many of the bees from flying off or crawling over the sides of the hive body. The rest of the colony with the queen we put together and place this modified swarm box on top of the hive, followed by the outer cover. We thus have a swarm box made up on top of a colony with the bees and equipment from that colony.
The bees confined in the swarm box are the nurse bees from the brood nest. They have no brood until they receive grafted queen cells. They are supplied with frames containing honey and pollen and are separated from the hive by a screen division board. The temperature of the bees in the swarm box is partly controlled by the colony below through the screen division board. Unless the colony is in the sun during excessive hot weather, we do not fear overheating the bees in the swarm box. However, these swarm boxes, as well as the other colonies used in queen rearing, should be in the shade.
In our operations we make up swarm boxes on four colonies just before noon. Immediately after lunch we give each swarm box four bars of grafted cells. For the first graft we use large larvae (about 36 to 48 hours old) and graft into dry cells. Any colony; usually a swarm-box colony, is the source of the larvae for this first graft. Each bar of cells has 20 to 23 cells. Two bars of cells to a frame and two frames of grafted cells to each swarm box give approximately 80 to 90 grafted cells to each swarm box.
We place the two frames of grafted cells in the swarm box with one frame containing honey and pollen between the frames of queen cells and the other frames of honey and pollen next to the frames of queen cells. When removing the outer cover and the inner cover to insert the frames of queen cells into the swarm box, we use very little smoke and do not worry about the few bees that fly out. These are field bees anyway and are of little value in the swarm box.
Twenty-four hours later (the next afternoon) we remove the cover from the swarm-box colony, lift the swarm box off, remove the screen division board, replace the swarm box on the top of the colony (now united by the removal of the screen), remove the two frames of queen cells, push the remaining frames together, add two empty combs to fill up the space, put the inner cover on the hive, place the screen division board on it, and finally put the outer cover over all. When the colony is closed, all we have left on the outside are two frames of queen cells that are well supplied with royal jelly and covered with bees.
After we have emptied all four swarm boxes, we shake the bees off the started queen cells and take them to the grafting house. Here we consolidate the accepted cells of the 16 bars of cells into 12 bars. Each bar has 20 to 23 queen cells. We now remove the queen larvae from these queen cells and are ready to regraft into queen cells that are well supplied with royal jelly.
We regraft with 24-hour larvae from our breeder queens and give one bar of regrafted queen cells to each finishing colony.
The finishing colony is most important in the rearing of good queens. It is a very populous, queen-right colony in which brood rearing is never restricted. To provide ample space for such a colony, at least four shallow hive bodies are necessary. We use the upper hive body for finishing queen cells and confine the queen to the lower three hive bodies by an excluder. We place the frame for queen cells in the middle of the upper hive body between frames of unsealed brood.
On the day before giving a finishing colony a bar of queen cells, we raise three to six frames of unsealed brood and move the older sealed brood to the brood nest below the excluder. The main brood nest of the queen in the finishing colony is in the hive body just below the excluder. She can expand into the lower hive bodies.
When working a finishing colony to raise young brood, we put the heavy combs of honey to the outside in the lower hive body and move up partly filled combs to the upper hive body so that the brood nest does not become crowded. The bees will keep moving the honey up if it is not sealed. It is not necessary to feed a good colony of bees to stimulate or keep brood rearing or queen rearing progressing at a high rate, provided the colony has ample food.
When a heavy honeyflow is on, we add a fifth shallow hive body, placing it on top. This helps to keep the brood nest open by giving more space outside the brood nest for nectar storage. However, it is not advisable to have frames of empty combs just above the queen cells. They should be near the outside of the super.
Seven days later we give another bar of cells to the finishing colony after young brood has been raised above the excluder.
Ten days after the queen cells are regrafted we put the cells into the nuclei at the mating yard. Our nuclei hold four shallow frames. We use a triple “nuc” box formed by dividing a super into three compartments. Each “nuc” has two auger holes one below the other, and the three nuclei in each box have similar holes on different sides of the hives.
No colonies are placed in the mating yard. Strong colonies may incite robbing with the result that nuclei may be robbed out. Our drone-producing colonies are our cell-finishing, swarm-box and reserve colonies located no closer than 250 yards from the “nuc” yard.
The breeder queens used on the island are of one inbred line artificially mated to drones of another. They are not so vigorous or such good layers as noninbred or hybrid queens, and therefore require different care than the commercial queen producer is accustomed to providing.
These breeder colonies must get help from other colonies to insure adequate numbers of young bees to keep them populous. If a breeder colony is allowed to become weak, the egg production of the queen will decline and the larvae used in grafting to produce hybrid queens will not be well supplied with royal jelly previous to grafting. Should this happen, both the quality and the quantity of the hybrid queens will be lowered.
To keep an ample population in a breeder colony, we must add young bees at frequent intervals. In our operations at Kelleys Island we use the two-queen colony system. Figure 1 shows how such a colony is made up and organized. It is not difficult to operate, and its use insures a steady addition of young bees to the breeder colony without great danger of losing the breeder queen.
We introduce the breeder queen into a newly made-up colony. When she is well established and laying satisfactorily, this colony becomes the top unit of a two-queen colony. The queen in the lower unit, or booster colony, is a good vigorous hybrid queen and furnishes young bees for strengthening the upper unit.
The procedure for establishing a two-queen colony is as follows: We move a first-class colony to a location convenient to the grafting house. This colony is in a shallow four-story hive with the brood nest in the lower three hive bodies. After the colony becomes established, in two or three days, we consolidate the queen and all her brood in the lower three hive bodies, place an excluder above and below the fourth hive body, and the two-story breeder colony on top of this booster colony. All hive bodies with brood have 1-inch auger-hole openings at the front of the hive. The entrances to the two units of this now two-queen colony are on the same side of the hive. The bees of both units mingle, but the two brood nests are separated by two queen excluders and a super for storage between the excluders. Bees from the lower brood nest go to the upper brood nest through the excluders and help keep this upper unit populous. Returning field bees, using the auger-hole entrances, tend to drift to the upper breeder unit, keeping the population ample in this unit.
During a honeyflow the bees tend to crowd honey into the brood nest of the breeder unit. Since the queen producer is grafting from this colony every few days, he can easily keep an open brood nest in the breeder nest by moving frames of honey to the lower unit as space for brood rearing or honey storage is needed. It is advisable to check the lower unit of this colony once a week to prevent overcrowding or swarming.
Since the two brood nests are separated by two excluders and the intervening super, there is no danger of the two queens coming in contact with each other. Because there is always danger of a virgin queen entering the breeder colony and killing a valuable queen, a small square of zinc excluder is placed over the anger-hole entrances of the breeder unit. Bees passing through zinc excluders lose part of their pollen loads. Thus it is advisable to watch the supply of pollen in the breeder unit and add a frame of pollen when necessary to insure proper feeding of the larvae.
The queens produced at Kelleys Island are two-way hybrids. An inbred queen of line 3 artifically mated to drones from inbred line 4 is the source of the hybrid queens (3 x 4). The beekeeper who purchases these queens has hybrid queens (3 x 4) heading his colonies. Since all drones on the island are sons of (1 x 2) hybrid queens, the worker daughters of these hybrids queens will be (1×2) x (3×4) double hybrid workers in a colony headed by a single hybrid queen. If, in addition, the opposing sex alleles in the final cross are different, the hatchability will approach 100 per cent and the brood quality will be excellent.
To provide the bee industry with the foundation stock for the production of such scientifically compounded hybrids, adapted to various purposes and various localities, is the objective of the Kelleys Island breeding project that is being conducted in cooperation with the Honey Bee Improvement Cooperative Association.
For Further Reading
Crow, James F., and William C. Roberts. 1950. Inbreeding and Homozygosis in Bees. Genetics 35: 612-621.
Hagedoorn, A. L. 1948. Animal Breeding. 337 pp. Crosby Lockwood & Son, London.
Kalmus, H., and C. A. B. Smith. 1948. Production of Pure Lines in Bees. Jour. Genetics 49: 153-158.
Lush, Jay L. 1949. Animal Breeding Plans. 438 pp. Iowa State College Press, Ames, Iowa.
Mackensen, 0. 1951. Viability and Sex Determination in the Honey Bees. Genetics (In Press).
Mackensen, 0., and W. C. Roberts. 1948. A Manual for the Artificial Insemination of Queen Bees. U. S. Bur. Ent. & Plant Quar., ET-250, 33 pp.
Malin, D. T. 1923. The Evolution of Breeds. 262 pp. Wallace Publishing Co., Des Moines, Iowa.
Polhemus, Martin S., Jay L. Lush, and Walter C. Rothenbuhler. 1950. Mating Systems in Honey Bees. Jour. Heredity 41: 151-155.
Whiting, P. W. 1940. Multiple Alleles in Sex Determination of Habrobracon. Jour. Morphology 66: 323-355.
Wright, S. 1933. Inbreeding and Homozygosis. Proc. Nat. Acad. Sci. 19: 411-420.
Reprinted from AMERICAN BEE JOURNAL
No. 11, pages 473-475, November 1951