The early Life of a Honey Bee Egg

A tiny white egg (looking like a miniature grain of rice) standing on end in a cell of the comb. Eggs are not much longer than a typewritten dash ("-") (1/16 inch) and weigh almost nothing (0.12-0.22mg). Although they are easily seen, some beekeepers struggle to see them, probably because their eyesight is worse than they will admit.

Larvae and capped brood, but no eggs?

The larval stage lasts about 5.5 days.

Too many eggs - in fact, multiple eggs per cell?

It could be laying workers. This is not good news. Worker bees can't mate nor store sperm. They're also missing genital structures and some behavior patterns. In essence, an adult worker honey bee cannot become a true queen. Since laying workers cannot fertilize eggs, any eggs produced become drones. Fertilized eggs (32 chromosomes) become either queens or workers, while unfertilized eggs (16 chromosomes) only become drones (males). Laying workers will generally develop within 23-30 days or so. The colony will be weak and its hive members old. It's probably not worth saving - but it will have eggs all over the brood nest area. In this case, abundant eggs per cell are not good.

There are other times when a colony with a perfectly good queen can have multiple eggs within single cells. If, at any time, the beekeeper introduces a strong, productive queen into a small, but biologically balanced colony, the queen's egg output may exceed the smaller colony's ability to provide space for all the eggs. In that case, it is common for a queen to place two or more eggs per cell. But, in this case, all eggs are fertile and the colony is in no danger of collapse. In this case, abundant eggs per cell are good (or at least okay).

What happens to extra eggs within single cells? They are probably eaten by nurse bees, though not necessarily very quickly. It may take several hours even to a couple of days for nurse bees to remove either dead or misplaced eggs. In fact, when grafting larvae for queen production, I've frequently seen two eggs, and later two larvae, occupying the same cell. I've wondered, given the tremendous growth rate of larvae, if occasionally one larvae eats the other or is it always the nurse bees?

Biology and behavior

The egg is a hardy developmental stage of the bee's growth. It is attached to the bottom of the cell with a glue-like substance secreted by the queen. It always has the small end down. It's an iridescent white with an ever-so-gentle curve to it. The egg is positioned with the to be larva's head-end up. After about three days, the egg gradually leans over until it lays on its side on the cell base. The egg's outer membranous covering (the chorion) slowly dissolves as the larva emerges. It's a slow, quiet process. Nurse bees soon begin to place hypopharyngeal gland secretions (brood food) around and under the larva which has a voracious appetite. Beekeepers frequently say that an egg hatches when referring to a larva emerging. As such, the bee egg does not "hatch", though the word transfers the concept. However, due to the membrane dissolution, rather than cracking as in a birds egg, it is called "eclosure" rather than "hatching". Though the egg normally develops within three days, it's reported development range is 2 - 6 days. Temperature appears to play a role in the duration of the egg's development. Eggs can commonly withstand room temperature for several hours without the ill effects shown by larvae and pupae held under the same conditions.

Haploid (drone) verses diploid (female) eggs.

The egg is filled with cytoplasm, a nucleus, and a yolk. The nucleus is near the big end of the egg and plays a major role in the development of a future bee. A newly fertilized honey bee queen will have nearly seven million sperm stored in a special pouch - the spermatheca. Sperm can be stored there, apparently in somewhat of a suspended animated state, for several years. Adult female worker bees can't do all this, hence a major difference between the anatomy and physiology of workers and queens. The adult, fertile queen has a muscular valve and pump which are used to withdraw a small amount of sperm from the spermatheca, pump it down the duct to an opening in the vagina where a vaginal valvefold forces the egg's micropyle (an opening in the larger end of the egg) against the opening of the vaginal sperm duct. The connection made, one or more sperm is passed into the egg. The newly fertilized egg becomes diploid (a full chromosomal content) and develops into a female. Shut down the entire sperm-releasing mechanism and the egg remains sperm-free, resulting in a haploid egg (one half of the chromosomal number). The unfertilized egg becomes a drone. A queen can seemingly tell a worker cell from a drone cell by measuring the cell diameter with her front legs and will deposit the appropriate egg. However, mistakes are occasionally made. Nurse bees, ever alert to errors, clean up the mistake by eating the errant egg.

The egg output of a good queen

This simple question is still not answered conclusively, though many respectable estimates have been made. The most accepted estimate is 3000 eggs per day during the height of the egg-producing season. This is about twice the weight of the queen and is about 1,500,000 eggs for her entire career (a little less than three years). This estimate is dependent on many factors - temperature, food availability (including pollen), and inherited characteristics.

Ironically, our view of the queen as a regal monarch is not a good one. The queen literally has food stuffed in one end while eggs are pushed from her other end - probably about one egg per minute - not exactly a leisure life. Nurse bees can control the egg laying rate by controlling the food input. Slow the food input and the egg rate drops. Other house bees are responsible for preparing cells for receiving eggs. Incoming nectar and pollen may also affect the egg flow by directly affecting the nurse bees that care for the developing brood. So the queen systematically (if she is a good one by our beekeeper standards) searches for prepared cells. Upon finding one, she puts the appropriate egg (drone or female) egg in the appropriate-sized cell. If she's not fed well, or if clean and polished cells are not ready, she decreases egg laying proportionally, but apparently it was not her decision to do so. If the queen can't produce enough eggs when pushed to do so, she will be superseded by the same nurse bees. There's not much of a retirement plan for queen bees. There's no cause to make honey bee eggs any more or less important than they should be. However, due to their small size and their quiet existence, I don't know if they always get their due regards. Even in this article, I skimmed over the amazing biological complexity and changes that occur within eggs after fertilization. Though biologically interesting, I'm not sure it's beekeepingly useful. However, as a beekeeper, eggs give me useful information concerning the presence (or absence) of a queen, an in dication of her performance, the overall health of the colony, and an estimate of the colony's immediate future. Even though they are small, they can tell you a lot - if you can see them.

Originally written by Dave Cushman. Edited by Roger Patterson.

Page created 21/08/2002

Page updated 01/12/2022