Counting Bees

Yesterday I failed to answer the question "How many bees are in there?" about our observation hive. Today I bring you an answer. At least, the best answer I can give you without putting on a bee suit.

5,460 bees in the observation hive!

"That's very specific," you say. You wonder, "How did she get that number?" Well, I am going to answer that question too. I read a scientific paper to figure this out. A scientific paper is an essay that scientists write to tell each other about their experiments.

The paper I read is by Michael Burgett and Intawat Burikam, and was published in 1985.

In this paper, the authors describe an experiment to find out how many bees can live on a standard frame (one of those wooden rectangles with a honey comb in it). They took one frame at a time and two people looked at the frame to estimate what percent of the frame was covered with bees. For example, if only half of the frame had bees on it, they called it 50% covered. If all of the frame was covered by a layer of bees, the frame was 100% covered. Then they took the frames and killed all of the bees with gas (sad!). They killed the bees so that they could weigh them more easily. Don't worry- there were a lot more bees still in the hives. They used our method of weighing the bees to figure out how many there were. So they could use their percent covering estimates and pair them with a number of bees to estimate how many bees on average could fit on the frame (with the help of some secondary school math).

For the size frame that we use, they estimated that 1,820 bees was the largest number of bees that you could fit on a frame. There were 3 frames in our observation hives. If all our frames were 100% covered, that would mean that:

1,820 * 3 = 5,460 bees in the observation hive!

5,460 bees in the observation hive!

That's a lot. To give you an idea how many, the number of people in Philipsburg is about 5,480. So that means you had almost the entire population of Philipsburg (in bees!) on your desk.

How many bees are in there?

Several of you asked about how many bees there were in the observation hive. Boy, my first question and I'm going to failboat it. I have no idea. A lot. A whole lot of bees.

If we wanted to know the answer to that, how could we find out? (Remember when we talked about "finding things out" as a definition of science?) Think about it...

Ok, here are some ideas I came up with:

1) Count them one by one. This would be really hard because the bees move around so much. Maybe instead of counting them while they are moving, you could take a photo and count them in the photo. This would take a long time. Maybe I could write a computer program to count bees in the photo for me. But then what about the bees that are hiding in the cells (the holes in the honey comb)? I don't think this is the best method.

2) Weigh them. First, weigh groups of bees, maybe 10 to 20 bees at a time in a cup. Subtract the weight of the cup and then divide by how many bees you weighed to figure out about how much a single bee weighs. Then take all the bees out of the hive, shake them into a bucket or something and weigh all the bees, subtracting the weight of the bucket. Divide this weight of all the bees by the weight of a single bee to figure out how many bees there are.

Let's do the math!
Say I grab 10 bees in a net and put them in a jar and the jar full of bees weighs 50.3g (grams). I let the bees go, then weigh the empty jar (with its lid) and it weighs 49.3g.

50.3g - 49.3g = 1 g
Means that the 10 bees (without the jar) weigh 1 g. That means that each bee weighs 0.1 g (1g / 10 bees = 0.1g) or one tenth of a gram.

Next step- get all the bees out of the beehive and into a bucket. I'd need a bee-suit to keep me from getting stung. and a smoker to make smoke. Smoke makes the bees think that there's a fire, so they start drinking nectar and honey and mostly ignore beekeepers. I'd take my hive tool too. It's a little pry-bar for separating the boxes and frames of the hive. Bees like to seal everything up with "bee glue," so beekeepers need to have a hive tool to pry things apart in the hive.

I'd open up the cover and pull the frames out one at a time, shaking the bees off into a bucket with a lid. Bees would be flying around everywhere every time I shook a new frame or opened the bucket. It would be really hard to get all of the bees off of the frame because they cling to the frames really well. Once I shook all the bees I could into the bucket, I'd have to go weigh the bucket. Let's say the bucket full of bees weighed 1,627 g. After I dump all the bees back into the hive, I weigh the bucket (maybe I should have done this before I put the bees in, eh?), and it weighs around 907 g. Then I subtract the weight of the bucket from the weight of the bees+bucket to get 720 g for the weight of all the bees in the observation hive. Since we measured the weight of one bee to be 0.1 g, we divide 720 g by 0.1 g to get 7,200 bees! I told you it was a lot of bees!

What's that you say? I didn't actually do the experiment? I can't say that I have 7,200 bees when I never weighed a single bee? Ok, well then I'll get the bee-suit out and you can help me.

Oh- you don't want to do all that work to get that number? You don't want to even have to go outside? Boy, you guys are lazy! Then again, maybe you have a point. When I shake all the bees out of the hive, I will probably end up hurting a lot of them. A bunch of them will fly away and never make it in the bucket anyhow. And I would never want to lose the queen bee! Next time, I'll reveal a simpler and easier way to estimate the number of bees in my observation hive.