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Emergence box vs hatching box: what’s the difference?

Sometimes I use the wrong word. Yesterday, when someone asked, “What’s a hatching box?” I felt sheepish. I should have written emergence box in my post on lovage. Here’s the question:

I planted some lovage, and I too thought the stems would make good nesting tubes. So now I must ask, what is a hatching box?

Carin

What’s a hatching emergence box?

An emergence box is used for cavity-nesting bees such as mason bees and leafcutting bees. It is simply an empty box with a lid you can open. In the center of one side is a small hole, big enough for bees to pass through.

To understand the purpose of an emergence box, you need to look at the behavior of cavity-nesting bees.

Tubes and tunnels

Cavity-nesters are the bees that nest in holes bored into wood or in empty reeds and hollow stems. The female lays her eggs, one at a time, by starting at the back of the hollow space and working toward the opening. These bees usually partition the space between each egg.

In nature, these convenient nesting spaces don’t last very long. A tree with many cavities drilled by birds or beetles will eventually rot and fall. Reeds and hollow stems, such as raspberry canes or teasel stems, collapse after a season. This constant destruction of nesting sites means wild bees are always looking for new ones.

New sites are best

If the opportunity exists, cavity-nesters will nest in the same tunnel they emerged from. But if they use the same tunnels year after year, parasites, predators, and disease organisms multiply. Eventually, the nesting environment becomes so unhealthy that the baby bees can’t survive. But natural housing rots and falls apart, so it forces the bees to find new clean homes. Nature’s way works.

In the meantime, beekeepers offer these bees sturdy homes made of drilled wood, bamboo tubes, or other materials that can survive year after year. Predictably, the parasites, predators, and pathogens thrive. In fact, because of the lack of social distancing in beekeeper-provided housing, the pest populations can explode. After a few successful years, some keepers lose all their wild bees to things like parasitic wasps, pollen mites, molds, and fungi.

Enter the emergence box

With an emergence box, you can force your bees to use new tubes instead of the old ones. It works like this:

Bees prefer nesting tubes bathed in sunlight. They don’t like to go into dark places to look for a nesting place. Most won’t do it.

An emergence box takes advantage of this preference. Simply mount your fresh new housing and put the emergence box nearby with the hole facing the sun. Then put your cocoons—or even full tubes of cocoons—in the box. As the bees emerge within the dark box, they will see the dot of sunlight and fly outside for eating and mating.

But when it comes time to start nest building, they will not want to go into the dark interior of the box to find their old nesting tube. Instead, they (usually) select the shiny new tubes you have prepared for them.

I say “usually” because occasionally you will find a bee that insists on defeating your plans and nesting inside the dark box. There’s nothing you can do for these outliers; some kids are a mess from day one.

Designing an emergence box

Wooden boxes work best, but you can also use cardboard if the box won’t get wet. I like to use an empty honey super with an entrance hole drilled in one side. Then I add a bottom board and a lid.

Place your emergence box next to your nesting tubes, the closer the better. The single hole should face south or southeast and receive unobstructed sunshine. Once all the bees have emerged, you can remove the box.

Hatching is different

Larval bees hatch from eggs, but adult bees emerge from cocoons. Because you will fill your box with cocoons, the bees coming out will be adults. For that reason, the phrase “hatching box” is technically wrong and I should have said emergence box.

Rusty
Honey Bee Suite

Sometimes I use an empty honey super as an emergence box. In this photo, the upper box isn't necessary, but I put it there so the lid wouldn't shade the opening.
Sometimes I use an empty honey super as an emergence box. In this photo, the upper box isn’t necessary, but I put it there so the lid wouldn’t shade the opening. Photos by Rusty Burlew.
Cardboard containers make great emergence boxes. Just punch a hole in the box, making sure the layer of cocoons doesn't cover the hole.
Cardboard containers make great emergence boxes. Just punch a hole in the box, making sure the layer of cocoons doesn’t cover the hole.

Comments

Lisa Robinson
Reply

Thank you. I have some condos made from drilled boards. They are Melanosmia bees, smaller than blue orchard bees and the old house was drilled with smallish short tunnels compared to the standard mason bee hole. I put it out next to the shiny new WeeBeeHouse I purchased. The bees preferred to reuse the old condo I was planning to retire. I think the width of the hole was part of the problem, or maybe they thought the too new linseed smell too strong?

Next year I will put the entire old condo into a box and see if that stops them from coming back. Hope that works!

Rusty
Reply

Lisa,

It could also be some kind of pheromone. Bees seem to prefer used housing, which is why sometimes we need to trick them into using the new stuff. I find that putting entire condos into an emergence box helps a lot, but some stubborn ones will always go into the dark box.

Marilyn
Reply

Hi Rusty,

Every year I use both drilled blocks and tubes for mason and leafcutter bees. This past spring I put the blocks in a cardboard box with a couple of pencil-sized holes and a bunch of new tubes on top of it. Guess what? The bees emerged and started going back in right away! This seemed so continuous that I never felt it was time to remove the cardboard box of blocks. This continued through the leafcutters. So now I have blocks full of bees again. Guess I’ll have to try something different next year, huh?

Rusty
Reply

Marilyn,

You can try turning the emergence box so the holes face away from the sun, but keep the new tubes facing the sun. Although the bees may emerge a few days later, it may be worth a try.

Pam
Reply

Enjoy your newsletter and this post as well! We made our first box last year and have some renters!! We will definitely follow your advice to replace the nesting medium each year. This made me wonder…when will our bees emerge? We live in southern NH close to the coast zone 6A. Also, what is the approximate date range for nesting to start? Any help or references are greatly appreciated!!

Rusty
Reply

Pam,

Emergence and nesting vary according to the species and to local conditions. The easiest way to estimate emergence this year is by the nesting behavior last year. It happens fast, so as soon as they emerge they begin to nest. If your renters appeared last year in, for example, April, expect to see some action at about that time.

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