Lesson 5 – The Honey Bee Caste System

Honey bees are in the  order Hymenoptera. This is the third largest group of insects comprising over 150,000 species. This group consists of ants, bees, wasps, and sawflies. One distinguishing characteristic about this group is they are Eusocial. Eusociality is defined by the division of labor in the superorganism divided by groups such as reproductive and non-reproductive members. This is termed a Caste structure.

Honey bee colonies have three basic members: The Queen, Drones, and Worker Bees.

The Queen

queen (2)

The Queen is a mated adult female, and is usually mother to all in the hive. She is usually easy to identify in the hive based on her large abdomen. There is typically only one Queen per hive.

Queens begin as an fertilized egg just as any other bee in the hive. The worker bees select specific larvae to become a queen (See my blog post on “Types of Queen Cells” for more information) . They feed her a diet exclusively of Royal Jelly.

It takes 16 days for a new queen to emerge from the day an egg was laid. The first thing a virgin queen does after emerging is seek out rival developing queens, and kill them by stinging them. Typically, other than supersedure queens (queens made by the hive to replace existing queens), the virgin queens will not kill their mother. It is not uncommon to find a mother and her daughter in the hive at the same time.

Her next step is to get mated. She mates in the air on what is termed a mating flight. She will mate with between 12-20 drones (male bees) in flight. She may 2 or more flights to get properly mated.

After mating, she is ready to begin her role as the Queen of the colony and the sole fertilized reproductive member, and laying up to 1,500 eggs per day (during the spring build up).

The Drone

IMAG0226Drones are male bees. They develop from unfertilized eggs. Drones are larger bees with no stinger. They do not store or gather pollen or honey. The only function of a drone is to mate with a Queen.

Chromosomes are the packaged structures located in cells containing most of our DNA. In bees, the fertilized eggs are diploid. This means they have 32 Chromosomes, or 1 complete set of 16 from the mother and the father. Drones, however, are haploid. Because they come from unfertilized eggs, they IMAG0227 (3)have only 1 full set of chromosomes. This set comes from the mother. Drones have no father. This is interesting because it means that drones multiply to that magic number series in nature: Fibonacci. The Fibonacci series is located all through nature in plant and animal growth. Mathematically it is computed by starting with 1 (or 0 in some cases) and adding the two previous numbers.

1,1,2,3,5,8,13,21,34, etc

1+1 = 2      1+2=3   2+3=5   3+5=8

IMAG0227 (2)Drones eggs begin being laid as soon as resources are available in the Spring, and they cease as Fall comes to an end. Drone cells are laid in larger cells typically around the bottom of the frame. They are easy to spot. Their  “bullet” shaped cappings protrude from the frame. Drones take the longest to emerge. From the date an egg is laid, it takes 24 days for a Drone to emerge. After emergence, it takes about 12 days +/- for them to become sexually mature.

Once sexually mature, they wait for a queen to mate in Drone Congregation Areas (DCA). DCA’s are in the same place year after year. There is little known about why, however there must be some environmental cues the Drones get to assemble in these areas. A typical mating flight is usually around 20-30 minutes before having to return to the hive to “refuel” on honey.

Only the fastest Drones get to mate with the queen. This is one advantage Africanized bees have. The drones in Africanized hives are faster and stronger than their European counterparts. This is one drawback in openly mating queens in the southern US. The Male chromosomes are critically important in the behavior characteristics of the hive. If a European Queen is mated with Africanized Sperm, the resulting progeny will exhibit many of the same traits as the Africanized colonies. For this reason, many southern beekeepers either purchase queens to increase, or artificially inseminate their queens.

Drones mate with the Queen in the air. Each mating lasts around 5 seconds. Once the seminal fluid is transferred, the endophallus is broken off, and the Drone dies.

Drones consume a lot of resources in the hive, and contribute nothing. Therefore in late fall, or in times with a dearth of pollen and nectar, the Worker bees will stop the laying of Drone eggs, and push all of the Drones out of the hive to die.

Worker Bees

IMG_1510The last caste are the Worker bees. There are typically 50,000 of them in a hive. Worker bees come from fertilized eggs that take 22 days to develop. Once they emerge, they have their own caste structure called temporal polyethism. This is defined as an age related division of labor.

HIVE BEES – AGE 1-18 (+/-)

From ages 1-5 (after emerging), they clean out , and cap cells. When a new bee emerges, the cell contents must be cleaned out before a new egg can be laid.

From ages 5-15, they are nurse bees. They tend to the brood, and attend to the queen.

From ages 12-18, they are enlisted in nectar ripening, comb building, nest homeostasis, Food exchange and handling, as well as hive odor.

FIELD BEES – AGE 18-21 +/-

The last stage is foraging for nectar, pollen, water, and propolis. This is usually the last task they will do before they die. Foraging is a hazardous duty. Foraging bees get lost, get eaten by predators, or starve. If they due manage to die of old age, it is usually about 21 days after emergence.

Bees can advance and regress up and down these tasks based upon the demand of the hive. If there is a lack of foragers, younger bees can become what is called precocious foragers which may only be a week old. On the other scale if there is a shortage of nurse bees, older bees can come and help tend to the brood nest. There is much flexibility throughout the system based upon the needs of the hive itself.

One thought on “Lesson 5 – The Honey Bee Caste System

  1. Pingback: Eusocial Insects

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