Why are some cells darker than others?

When the comb is brand new, it is white to light yellow. When the bees make new comb we call it "drawing out the comb." Here is a freshly drawn comb.

The comb starts to get darker as it ages. Depending on what is stored in the comb, it will get darker faster. Honey comb doesn't get very dark because honey and nectar are almost clear and cannot color the comb very much. Cells in comb that are used for baby bees (eggs, larvae, and pupae), however, get very dark. That is because that honeybees, like moths, spin a cocoon when they pupate. This cocoon is made of silk strands that come from the mouth of the larva inside. You can't see the cocoon very well because of that wax cap the worker bees put over the cell when the larva when it starts to pupate. Even when you cut open a cell, it is very hard to see the cocoon because it is so thin and sticks to the wall of the cell like wallpaper. The cocoon is darker than the wax, and it makes the wax cells look darker. Once a bee has emerged from a cell, the cell can be re-used for a new larva, so the next larva will spin its cocoon inside the old cocoon of the last larva. The cocoon layers build up like a stack of paper until the cells look very dark indeed. Here is a cross-sectioned (sliced open) cell with an egg. See all the layers at the bottom? Those are old cocoons built up over years.

The pollen also colors the comb. Pollen is usually yellow, but can be brown, red, orange, white, and even purple.  These colors all get mixed up when the pollen is stored in the cells to make bee bread. The wax gets stained or colored by all the pollen and starts to look dark.


New comb photo from UNL extension.

What's in the cells?

The cells are the holes in the honeycomb. They are all-purpose cubbyholes for the bees. Kind of like your desks at school, they use them to organize all their stuff. What kind of stuff do bees have to organize? Lots of stuff!

These are the baby bees. Each baby bee gets its very own cell. They start out as tiny eggs laid by the queen in the bottom of each cell. After they hatch, they are worm-like creatures called larvae. The nurse bees feed them royal jelly, the shiny white liquid around the larvae in this photo. They get bigger and bigger until they pupate, or turn into a pupa inside the cell. The pupa stage is hard to see because as soon as a larva is ready to pupate the worker bees cover up its cell with a cap. Like this:

The cap on the cell is made of wax like the rest of the comb. It protects the pupa from damage. The pupa doesn't eat, so the nurse bees don't need to keep feeding it. Inside the capped cell, the pupa develops into an adult bee.

Here is a newly emerged honeybee. She has just chewed through the cap on her cell and is poking her head out for the first time. She is still very soft and cannot sting or fly for about 24 hours.

Two other things that bees keep in the cells are nectar and pollen. This is their food. The nectar (shiny watery liquid in the above photo) is made into honey. The pollen (yellow powdery stuff in above photo) is made into nutrient-rich food for the bees called "bee bread." Bee bread is just pollen that has been processed by friendly microbes, kind of like the bread that we eat. Our bread uses yeast (a microbe) to rise and taste good.

When the nectar is made into honey, it will have a lot less water in it. The bees cover the honey cells with a wax cap like they do for the pupating honeybee larvae. The cap looks different, though.

So that's what the bees keep in the cells- eggs, larvae, pupae, pollen, bee bread, nectar, and honey! Everything that the beehive needs is stored in the cells.

Bee larvae, emerging bee, pollen and nectar photo by Flickr user Max xx. Capped brood photo by Flickr user KrisFricke. Capped honey photo by Flickr user willsfca.

What is that white thing?

We saw something extraordinary and amazing when we watched the beehive. We saw the bees carrying away something white and gooey. It looked a little bit like this.

They ripped it up into small pieces and several bees carried around these bits of white goo all over the hive as if on a mission. The piece of white goo was a bit of a dead bee larva or pupa. Here you can see what they look like when they are alive.

See the small white worms curled up in the bottom of the cells? Those are the larvae. When they get big enough to turn into pupae, the worker bees cover up the cell with a lid made of wax called a cap. That is what those cells are that have a brown cover on them.

You all learned that bees have different jobs in the hive. In addition to foragers that go out to collect nectar and pollen and nurses that feed the larvae, there are "undertaker" bees. Undertaker bees take away the dead and sick bees. Normally, they will take the dead or sick bee away and drop them outside the hive, but our bees couldn't fly out, so our undertaker bees had to keep carrying around the dead bee.

Undertaker bees are very important to the health of the honeybee hive. They are like the doctors of the hive. They observe the bees carefully, and when they sense a bee is sick or dying, they immediately take action to protect the rest of the hive by removing the bee. Scientists who study bees are very interested in finding out how these bees know when another bee is sick and how they decide it is time to remove the sick bee. Some kinds of honeybees, like those from Africa, are really good at removing sick or dead bees. We call these bees "hygienic" because that means they are good at keeping things clean. Other bees, like our European bees, aren't as good at undertaking. If we could find a way to teach our bees to be more hygienic, perhaps we could help solve some of the health problems our honeybees are having right now.

Photo of honeybee removing dead pupa by Kathy Keatley Garvey of the UC Master Gardener Program. Bee larvae photo by Flickr user dreamexplorer.

How do they choose the queen?

Last time we talked about what the queen bee spends most of her life doing: laying eggs. But what about before? How does she get to be the queen? Is there an elaborate ceremony there the other bees all bow and place a crown on her head?

Sorry, no.

The queen is picked at birth. When the former queen dies, the worker bees select an egg (or a itty bitty larva less than 3 days old) to feed and raise as the next queen. For its entire life, the tiny larva is fed with royal jelly. This royal jelly is a special milk made by the workers. It has lots of nutrients, so the larva grows big. She grows much bigger than a normal worker larva, and the workers build an addition onto her cell to make room. After she gets big enough to metamorphose (go from a larva to an adult bee), she becomes a pupa. The pupa is the stage of her life in which her body converts from a gooey white worm into an adult bee. After a little while, she is ready to emerge as the new queen.

In the normal life of the hive, sometimes the beehive gets too crowded. There are so many bees that they run out of room. It is time for the hive to swarm. Swarming is when the queen flies away with about half of the bees in the hive to find a new nest. The bees that are left behind when the hive swarms have to raise a new queen to take over the egg-laying in their hive. In this case, the old queen has already laid an egg in a special cell called a queen cup. The new queen will develop in the queen cup, fed constantly on royal jelly until she is big enough to be the new queen.


(Queen bee coronation illustration from flickr user art.crazed. Scanned from "The Bee," written and illustrated by Iliane Roels, Grosset & Dunlap, 1969. Queen larvae and queen pupae pictures by Wikimedia user Waugsberg.)