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.