Upright hollow stems: much better than toxic mason bee houses

Inside: Many solitary bees living close together provide a leg up to all the predators, pests, and pathogens that plague cavity-nesting bees. Upright hollow stems provide a healthy alternative to crowded conditions.

We all think, “It won’t happen to me. I’m careful, so my mason bees won’t have any health problems.” Trouble is, nature is an opportunist. If an organism sees a chance to thrive on the back of another, it will.

The rise of mason bees

In the last twenty years, orchard mason bees have exploded as household pets. They are often impulse buys, purchased after seeing a cute birdhouse-like mason bee condo in the aisle of a favorite store.

No doubt, mason bees and their close relatives the leafcutting bees are pollinating superstars. They are fast and diligent, pollinating many flowers and crops. And if you keep them in an easy-to-see location, they are mesmerizing to watch—much easier to view than honey bees inside a hive. Even better, they hesitate to sting and rarely confront a passive bee-watcher.

Unfortunately, lots of mason beekeepers have a “set it and forget it” mindset, a philosophy that seldom works long-term. Eventually, untended bees will die or move away.

Congested quarters can be deadly

As with many other creatures, large groups of mason bees become bait for organisms that can take advantage of them. The number of threats to cavity-nesting bees like mason bees and leafcutting bees is enormous. The list includes multiple types of mites, wasps, birds, fungi, molds, and pathogens.

These threats occur naturally in the environment, appearing pretty much everywhere. But as the pandemic reminded us, when individuals live and work close together, diseases spread like wildfire, fast and furious. Parasites and predators also delight in finding a cache of closely spaced victims and will pounce on the goldmine of nutrition the bees provide.

Even though many of the solitary bees are gregarious by nature—often living close to one another—they don’t live as tightly packed as they do in a bee condo. They naturally spread further apart, making each one safer from the things that might attack. A bit of social distancing goes a long, long way toward solitary bee survival.

Unlike honey bees, solitary bees need space

After seeing honey bees and social wasps living in massive colonies, we might assume dense living is normal for bees. But unlike solitary mason bees, social insects like honey bees live in colonies with multiple defenses against invaders.

Just as a herd of elk, a school of fish, or a flock of birds have crowd-sourced safeguards, so do colonies of insects. Often their defenses involve the sacrifice of some for the good of the group. But solitary bees are more like rabbits or moles or woodpeckers: their defense mechanisms don’t involve others. Even though solitary bees may live near members of their own species, in most cases they must defend themselves.

Like anything worthwhile, mason bees require effort

Unfortunately, there is more to raising mason bees than hanging a bee house on a post and walking away. Those cute miniature houses can actually be death traps, luring young solitary mothers to nest in a pit that attracts diseases and predators. It’s hard to imagine anything more ingeniously designed to fail.

Not only do dense bee settlements attract disease, mold, and fungus, but those woodpeckers, parasitic wasps, and mites also admire them. Sadly, most things that go wrong with mason bees go wrong right in their own home.

Yes, you can successfully raise mason bees in condos, bee houses, and drilled blocks, but it takes lots of effort. In addition, the various steps need to be addressed on time before the attackers win. It’s easy to forget a step or be late, or you may not enjoy it enough to keep going.

Remember all those people who got pets during the pandemic, and then turned them into a shelter after a year or two? It’s the same with mason bees: all the fussy, repetitive work could cause you to question your decision.

The progression of mason bee problems

The progression of mason bee problems usually follows a predictable pattern. When someone gets their first mason bee house, everything goes well for the first year, or sometimes even two years. If you’re lucky, your purchased mason bees didn’t come with many pathogens, so the first round of bees emerges, mates, and fills those new tubes with pollen and eggs.

But somewhere in their travels, the bees pick up pollen mites. So by the second year, there may be some bee losses caused by mites, and you may even find bees covered with thick layers of pollen mites. If the beekeeper doesn’t clean or change the nesting tubes in time, the bees lay next year’s bees in the contaminated holes. When that happens, beekeepers often say, “Oh well. They’ll be fine.” But they won’t; infestations rapidly get worse.

Also, after the first season, the local fauna has had time to discover the location of your bee community. Often by the third year, parasitic wasps hang around in great clouds. The worst of these, like Monodontomerous, are smaller than a fruit fly. But don’t be fooled: they are treacherous. They will lay their eggs inside the bee pupae. Then, when the wasp babies hatch into larvae, they will eat the developing bee from the inside out.

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Upright hollow stems: an alternative to bee condos

Growing plants with hollow stems is a healthy alternative to manmade bee housing. These are the types of nests cavity-nesting bees would choose if they were living in the wild. Several characteristics make upright hollow stems the very best bee housing.

First, the stems are spread further apart. In each bunch, a few may be close. But for most, there will be inches between each one. Also, the bunches themselves may be spread across inches, feet, or even yards.

The greater separation between nesting tubes makes it more difficult for diseases to spread and it makes it harder for birds and wasps to find them. In addition, birds can’t stand in one place and eat for hours. Instead, they must keep hunting, poking, and finding places to alight. The entire process is more difficult and time-consuming.

Another advantage is that the stems naturally fall over and begin to decompose after a couple of years, perfect timing for raising healthy bees. The latest generation of bees can still emerge from the toppled stems, but the current adults will not nest in them, so it’s a natural, no-effort cycle that keeps pathogen levels low.

Nature has this all worked out, yet we humans think we can do things better. But sometimes, that just ain’t so. The biggest drawback to using upright stems is the amount of long-term planning it requires.

How to grow upright hollow stems for your bees

Year One

• You must choose the right plants for your area, so you may need to consult your extension agent or local garden club for advice. You need plants that have either hollow or pithy stems. Some examples include lovage, elderberry, blackberry, teasel, drumstick allium, mountain mint, goldenrod, sunflowers, joe-pye weed, and swamp milkweed.

• At the end of the first growing season, cut the stems back to roughly 12 to 18 inches high. Using a sharp tool, try to make cuts smooth and straight for an attractive, non-threatening nest entrance.

Year Two

• During spring of the second year, cavity-nesting bees will use your upright hollow stems to build their nests. Leave these standing all year. Some species may produce brood late in the summer of the same year, but most, including your mason bees, won’t emerge until the following year.

• Also during the second year, you can start more plants for the next season, especially if you’re using annuals. Remember to cut the hollow stems back to 12 to 18 inches in the fall.

• In the late fall or early winter, some stems will remain standing but some may bend over or fall to the ground. Some people like to leave everything natural, not disturbing the stems at all; others prefer to cut the stems at ground level and store them in a cool, dry place just as you would bamboo tubes or paper straws.
  
  Either way is fine, but if you collect the stems, be sure to put them in an emergence box in the spring so the bees do not reuse the old stems. (Note: if you live in an area with wet winters, collecting the stems is better.)

Year Three

• In spring of the third year, bees in your first planting of hollow stems will emerge and many of them will nest in the stems from your second-year planting. Now you’re on a roll. You just have to keep going and you should have plenty of healthy bees to pollinate your orchard and garden crops.

Healthy bees are worth the effort

I hope you give this rotation a try. It sounds like a lot of work, but done properly, it can eliminate harvesting and bleaching cocoons, which is boring, time-consuming, and not natural at all.

Rusty
Honey Bee Suite

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