Counting the dead bees

You stroll past your hive for a quick peek and are dismayed to find five dead bees on the landing board. What does that mean? Is your hive in trouble? What should you do?

I can’t stress this enough: five dead bees is nothing. Nothing. The only difference between those five and a thousand of their sisters, is they happened to fall on the landing board. You aren’t worried about the other thousand because they fell somewhere else, a place where you can’t see them or count them.

I’ve read many estimates for the number of bees that die daily during foraging season, but depending on the size of the colony and local conditions, the real number is probably between 800 to 1200. For the sake of argument, I’m going to say 1000, which I think is a reasonable number.

The average lifespan of a worker bee

The first thing to consider is the average lifespan of an adult worker bee. For a healthy worker when all is going well, that lifespan is somewhere around 4 to 6 weeks. The period begins when the bee emerges from her brood cell and ends when she dies of old age or misadventure.

Old age is self explanatory and is often expressed by worn wings and hairless bodies. Misadventure can be due to anything, such as tangling with a spider web, getting blown away by the wind or smashed by a car, or getting diced by a lawn mower. As we humans say, stuff happens.

It turns out that four to six weeks is the number commonly cited for the average adult lifespan of most bees. That includes your mason bees, leafcutters, sweat bees, and miners. Basically, that’s how long bees working in the field live. The native bees emerge from their nests in spring and spend the next four to six weeks building a nest and laying eggs. They continue building until they die, and their offspring remain in the nest until the following year.

So in regard to an individual’s lifespan, honey bees are not unique. What is unique about honey bees is their ability to raise “winter bees” also know as diutinus or long-lasting bees. These bees are the ones that live inside the nest, survive the winter, and kickstart the colony the following spring. But that is another subject.

The egg-laying machine

The second thing to consider in a normal colony is the egg-laying ability of the queen. This number also varies, and I’ve read estimates that range from 1000 to 3000 eggs per day. To raise this many eggs, the colony needs a large force of healthy workers. Even so, we’re talking about a lot of eggs. Let’s take an average estimate of 2000 eggs per day during peak season.

Now, not all the eggs will grow into viable adults. Some will die at each stage of development. Let’s be conservative and say 80% reach adulthood. That’s .8 x 2000 or 1600 newly-hatched bees per day. If 1000 adults die during that one-day period, you still have a net gain of 600 bees. At the end of a month you have 600 x 30 or 18,000 more bees than you started with, even with losing 1000 per day. If 90% reach adulthood, you get 24,000 extra bees by the end of a month, which equals a good size swarm.

Yes, these are estimates based on averages, but they paint a picture. If you didn’t have all those bees dying each and every day, things would soon be out of control. If you took 90% of 2000 x 30 without deleting the dead ones, you’d have 54,000 additional bees at the end of a month—another whole colony. At the end of six months, you would have seven full-sized colonies. But it doesn’t work that way.

My point in reviewing the numbers is to illustrate that the daily loss of bees is much greater that we realize. The fact that we don’t see the dead, coupled with enormous amounts of brood rearing, lulls us into thinking that bees don’t die. In fact, nothing could be further from the truth.

Rusty
Honey Bee Suite