Larval Development
Navigation Menu
|
Development of Honey Bee Eggs
Within the Queen and after laying
|
|---|
"The early Life of a Honey Bee Egg"
tiny white egg (looking like
a miniature grain of rice) standing on end in a cell of
comb. Eggs
are not much longer than a typewritten dash ("-") (1/16 inch) and weigh nearly
nothing (0.12-.22mg) which means an egg doesn't weigh much more than
a
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 bee cannot become a true queen. Since
laying workers cannot fertili ze 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. e . 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 exc eed the smaller colony's ability to provide space
for all the eggs. In that case it is common for a queen to place two to
several eggs per cell. But, in this case, all eggs are fertile and the colony
is in no danger of collapse. In this case, abundant egg s 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 l arvae 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,
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 il l 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 pouc h - 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 adul t, 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 leg s 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 esti mates 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 estim ate 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 ñ not exactly a leisure life.
Nurse bees can control the e gg flow 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. The re'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 biologi cal 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.
| This page is either empty or part complete |
|---|
| The page itself either acts as a marker |
|---|
| Or as a link terminator |
|---|
| Or it has Navigation Menu links (see above left) |
|---|
| It is likely to be completed within a few
days, but there may be reasons that delay completion. |
|---|
| In some cases this page is a reminder for my future development of the website. |
|---|
| If the missing information covered under this
subject is of importance to you... please use the email button in the
strap at page bottom to request early completion. |
|---|
Originated... 21 Aug 2002, Revised... dd month 2002