What is a brood pattern?
Experienced beekeepers frequently talk about brood pattern. But what is a brood pattern and how do you tell a good one from a bad one?
A brood pattern is nothing more than the place where the queen laid her eggs. Simply put, the brood pattern is the shape of the brood nest. The queen lays her eggs altogether in a group, and the group has a characteristic shape that we call the brood pattern. It is easiest to see when the brood are capped with wax, but an experienced beekeeper can see the pattern even when the brood are in the egg or larval stage.
The capped brood are usually in the center of the frames, and since the cluster is more or less spherical, so is the brood nest. On cold days or nights, the cluster of bees is able to keep all the brood warm since the brood pattern mimics the shape of the cluster.
When you look at one frame you are seeing a slice of the brood nest. Think of a round loaf of bread. If you cut it in parallel slices, the pieces on the outside are smallest. As you get closer to the center of the loaf, the slices get larger and larger. After the largest slice, they begin to get smaller again.
It is the same with your brood pattern. The frames on the edges will have less brood than the frames on the middle, and the very biggest will be in the center. The bees usually store a layer of pollen around the brood nest, and above the pollen–and perhaps to the side of it–they store honey. Drone brood is often found along the bottom or the sides of the worker brood.
A slice (frame) taken from the center of the nest is often described as a rainbow–a layered arc consisting of brood, pollen, and honey. The nest is not always dead center in the middle of the hive, but it may be. Photos of good brood patterns are often so perfect that the beginning beekeeper thinks something is wrong with his bees. I’ve included a photo below that shows a pattern that you’re more likely to see–good, but not picture perfect.
Another important aspect of brood pattern relates to the number of empty cells. Some empty cells are normal and may even be used to warm the brood. But the brood cells should not be random or scattered; cappings should be uniformly brown or tan and not sunken. Too many holes in the pattern may indicate an old or failing queen, or they may indicate disease, or they may indicate a colony not large enough to care for all the brood. It is for these reasons that beekeepers use the overall look of the brood pattern as a measure of colony health.
The photo below shows a foundationless frame, not completely drawn out. The brood nest is skewed toward the front of the hive, but you can see that the pattern is solid with only a few empties. Pollen is stored in the uncapped cells on the perimeter of the brood nest and honey is stored in the upper corners. At the bottom of the brood nest is a spattering of drone cells. Although this frame doesn’t have a textbook pattern, it is obviously from a thriving colony. With a little practice, you will be able to identify a good pattern when you see one.