By GORDON D. WALLEREntomologist, Science and Education Administration, Carl Hayden Center for Bee Research, Tucson, Ariz. 85719.
BEEKEEPING IN THE UNITED STATES
AGRICULTURE HANDBOOK NUMBER 335
Revised October 1980
Pages 24 - 29
A honey bee begins life as an egg. Bee eggs develop in the ovarioles or small tubes that make up the two ovaries of a queen. The egg is nourished and grows as it moves down this tube. When it is fully formed, it reaches the end of the ovariole, then moves through the oviducts into the vagina. The sex of the new bee is normally determined as the egg passes through the vagina. A lifetime supply of sperm (5 million to 6 million) is stored by each queen in the spermatheca, a little globular sac attached to the vagina. The queen controls the release of sperm with the so-called sperm pump. If an egg is fertilized, it will develop into a female bee, but if not fertilized, a male bee will result. The result is that male bees have only one set of chromosomes (haploid) acquired from the queen.
The queen bee attaches each egg to the base of an empty cell in combs that have been cleaned by workers. The honey bee egg is a smooth, white, sausage-shaped object about 1.5 ml in length. During the first day, the egg nucleus divides-if the egg is unfertilized; or if the egg is fertilized, the fusion nucleus or zygote divides. It is not until the third day that the embryo form (with head and body segments) can be seen within the egg. The head is present at the larger unattached end and the back (dorsum) is on the in-curved (concave) side.
The first sign of hatching occurs when an egg is 72 to 84 hours old. Muscular contractions by the embryo cause a gentle, weaving motion that apparently results in a tiny hole being torn in the outer membrane (chorion). Fluid from within the egg soon emerges and covers the external surface. The embryo with its "tail" attached to the base of the cell continues to move about until its head also touches the base and an arch is formed. In this "croquet wicket" stage, the chorion evidently is dissolved. The larva then eases itself over against the bottom of the cell into the familiar C-shaped position (fig. 1).
Honey bee larvae are fed a nutritious substance called royal jelly secreted by the brood-food glands (hypopharyngeal glands) of young workers. During the first 24 hours, worker larvae are fed lavish amounts of royal jelly by older nurse bees. During the second 24 hours, they get very little additional food and thereafter are cared for by nurse bees of all ages. Pollen and honey are present in the food of older worker larvae.
Honey bees use two systems of feeding larvae. Young larvae are fed amounts excessive to their needs and older larvae are provided small quantities of food as needed. It has been estimated that 110,000 visits are made to a single bee during its egg and larval stages, 3,500 of these during the last 24 hours.
A female larva fed continuously on lavish amounts of royal jelly and provided a large, peanut-shaped cell will become a queen. Another larva given a mixture of honey and pollen during the latter half of its larval life and kept in a worker cell becomes a worker. The process that produces the complete expression of sexual characteristics in a queen has not been determined; however, it is considered to be caused by differences in both the quality and the quantity of the larval food provided.
Drone larvae grow larger than either workers or queens and, therefore, require more food. Food given to young drone larvae is nearly devoid of pollen and is milky-white, while that given to old drone larvae is a yellow-brown color and contains considerable pollen. The food given older drone larvae also is higher in pollen content than that given older worker larvae. Thus, both qualitative and quantitative differences distinguish the larval food given queen, worker, and drone.
The developing honey bee larva is a helpless creature whose principal function is eating. Both the malpighian tubules (analogous to human kidneys) and midgut are shut off from the intestine until a larva is nearly mature. In this way, body wastes are stored internally and the food surrounding each larva is protected from fecal contamination. The feces are expelled and pushed down to the bottom of the cell about the time the cocoon is made and after the larva has finished eating.
All castes of honey bees molt about every 24 hours during the first 4 days of larval life. When the ecdysis or molting occurs, the skin splits over the head and slips off the posterior end of the larva. This process normally takes less than 30 minutes. Each new larval stage (instar) is at first only slightly larger than the previous one, but it grows rapidly. The fifth larval instar gains about 40 percent of the total mature larval weight during days 8 and 9 (table 1).
BEEKEEPING IN THE UNITED STATES
AGRICULTURE HANDBOOK NUMBER 335
Revised October 1980
Pages 24 - 29
A honey bee begins life as an egg. Bee eggs develop in the ovarioles or small tubes that make up the two ovaries of a queen. The egg is nourished and grows as it moves down this tube. When it is fully formed, it reaches the end of the ovariole, then moves through the oviducts into the vagina. The sex of the new bee is normally determined as the egg passes through the vagina. A lifetime supply of sperm (5 million to 6 million) is stored by each queen in the spermatheca, a little globular sac attached to the vagina. The queen controls the release of sperm with the so-called sperm pump. If an egg is fertilized, it will develop into a female bee, but if not fertilized, a male bee will result. The result is that male bees have only one set of chromosomes (haploid) acquired from the queen.
The queen bee attaches each egg to the base of an empty cell in combs that have been cleaned by workers. The honey bee egg is a smooth, white, sausage-shaped object about 1.5 ml in length. During the first day, the egg nucleus divides-if the egg is unfertilized; or if the egg is fertilized, the fusion nucleus or zygote divides. It is not until the third day that the embryo form (with head and body segments) can be seen within the egg. The head is present at the larger unattached end and the back (dorsum) is on the in-curved (concave) side.
The first sign of hatching occurs when an egg is 72 to 84 hours old. Muscular contractions by the embryo cause a gentle, weaving motion that apparently results in a tiny hole being torn in the outer membrane (chorion). Fluid from within the egg soon emerges and covers the external surface. The embryo with its "tail" attached to the base of the cell continues to move about until its head also touches the base and an arch is formed. In this "croquet wicket" stage, the chorion evidently is dissolved. The larva then eases itself over against the bottom of the cell into the familiar C-shaped position (fig. 1).
Honey bee larvae are fed a nutritious substance called royal jelly secreted by the brood-food glands (hypopharyngeal glands) of young workers. During the first 24 hours, worker larvae are fed lavish amounts of royal jelly by older nurse bees. During the second 24 hours, they get very little additional food and thereafter are cared for by nurse bees of all ages. Pollen and honey are present in the food of older worker larvae.
Honey bees use two systems of feeding larvae. Young larvae are fed amounts excessive to their needs and older larvae are provided small quantities of food as needed. It has been estimated that 110,000 visits are made to a single bee during its egg and larval stages, 3,500 of these during the last 24 hours.
A female larva fed continuously on lavish amounts of royal jelly and provided a large, peanut-shaped cell will become a queen. Another larva given a mixture of honey and pollen during the latter half of its larval life and kept in a worker cell becomes a worker. The process that produces the complete expression of sexual characteristics in a queen has not been determined; however, it is considered to be caused by differences in both the quality and the quantity of the larval food provided.
Drone larvae grow larger than either workers or queens and, therefore, require more food. Food given to young drone larvae is nearly devoid of pollen and is milky-white, while that given to old drone larvae is a yellow-brown color and contains considerable pollen. The food given older drone larvae also is higher in pollen content than that given older worker larvae. Thus, both qualitative and quantitative differences distinguish the larval food given queen, worker, and drone.
The developing honey bee larva is a helpless creature whose principal function is eating. Both the malpighian tubules (analogous to human kidneys) and midgut are shut off from the intestine until a larva is nearly mature. In this way, body wastes are stored internally and the food surrounding each larva is protected from fecal contamination. The feces are expelled and pushed down to the bottom of the cell about the time the cocoon is made and after the larva has finished eating.
All castes of honey bees molt about every 24 hours during the first 4 days of larval life. When the ecdysis or molting occurs, the skin splits over the head and slips off the posterior end of the larva. This process normally takes less than 30 minutes. Each new larval stage (instar) is at first only slightly larger than the previous one, but it grows rapidly. The fifth larval instar gains about 40 percent of the total mature larval weight during days 8 and 9 (table 1).
Table 1. - Moults of the honey bee |