What's the Buzz About Bee Hotels and Bug Condos?

Many native bees nest in cavities in wood, hollow stems, or below ground. Besides growing native plants to support native pollinators, providing nesting habitat is also important. However, even if well-intentioned, some attempts at helping pollinators can have direct or indirect negative effects on biodiversity when ecology is not accounted for. The management of bees is a good example of such misplaced conservation practices. A 2022 study by Benoit Geslin, Lise Ropars, Marie Zakardjian, et al. called The misplaced management of bees, identified three successive errors in the management of bees: the multiplication of honey bee hives, the installation of insect hotels, the trade of solitary bee cocoons for release into the wild. Honey bees are a loaded topic for another day, but let's look closer at how bug hotels could be hurting more than helping. 

What's the Controversy?

More and more sources have been making strong claims for or against these backyard "bee hotels". These critiques have raised valid concerns about the risks of poorly designed or poorly maintained bee hotels. So far though, we really don’t have strong evidence for or against bee hotels as a tool for insect conservation. 

One risk is these bee hotels becoming easy opportunities for parasites, predators, and disease to thrive. Another valid concern is in some cases they are observed with higher occupation by non-native bees, but whether these issues are actually worse in bee hotels than in natural nests is not well understood.

"Trap nests" have been used in research, biological monitoring, and in orchard or agricultural settings for quite some time, so they do have a purpose beyond the backyard pollinator garden. The question is do they actually help wild bees? 

To make a statement one way or the other, we would need to know whether bee hotels consistently increase or decrease populations of wild, native bees, compared to a situation where no artificial nesting structures are provided. Some research is focusing on this area, but we still need a well-designed long-term study looking at the effects in the types of environments most homeowners are placing these nesting structures in. Until then, there are some ways to maintain your bee hotel to minimize the risks. 

What You Can Do

If you have a small bee hotel from a store like the one pictured above, there is not a great way to keep it clean and refresh the nesting materials. This is why some of the DIY options like the larger bug hotel below are better for long-term use in your backyard. Some orchards use similar structures to house mason bees to aid their pollination services and fruit production. 

The idea with a structure like this is to provide a wide variety of sizes and types of nesting materials, so there is an opportunity for more types of insects to use it. You can also discard and replace the materials as needed.

Cleaning the nesting cavities should be done after bees emerge and before they return to lay eggs inside. The timing will vary depending on what type of bees or wasps are using it, and if they emerge early or late in the season. For the cavities drilled in larger sticks, you can clean the holes with a pipe cleaner or using an air compressor to blow them clean. For the hollow tubes made of bamboo or other plant stems, you can replace these with cut up plant materials you can find. Lots of plant stems can be cut up and used for this. 

More than just bees will likely use a nesting structure designed for cavity bees. This includes spiders, wasps and other insects. Remember that wasps and other things are pollinators too, and they should be just as welcome in your artificial nesting structure as native bees as long as they are native to your region and not causing drastic harm to anything or anyone in your garden. 

You may observe complex ecological interactions taking place in your bee hotel like I did. This Cuckoo Wasp pictured is a parasitoid wasp that reproduces by entering a host's nest while the host is out. There she lays her eggs. The larvae of cuckoo wasps feed on the larvae of the nest-builder, usually another wasp.

What Do We Recommend Instead?

Bee Hotels can be a cute addition to the wildflower garden, but they are not set-it and forget-it like many people are led to believe. Evidence showing bee hotels support cavity nesting bee populations is weak, so the work involved in cleaning and maintaining it may not be worth the trouble. Consider our approach instead...

There are easier but less visually appealing options for providing nesting habitat for bees and insects in your yard or garden, and they support all kinds of wildlife beyond bees. The simplest is to leave natural and messy parts of your yard intact. If you have stumps or logs present, leave them there. Drill some holes into the stump to encourage insects to use them, or just wait for other critters to create the cavities.

After your flower stems have died and dried up, leave them alone for several years to hollow out and provide nesting opportunities. Next year's new foliage will grow to hide them anyways, but if you don't like the appearance cut some and leave 6-10 inches of the dead stems. 

You can also offer nesting habitat with leaf mulch, and leave some areas with sunny, bare soil for ground-nesting bees.

Leaving wild spaces and replicating them in the habitat we create with wildflower gardens is much more proven means of helping pollinators, it will cost you less and require little to no maintenance.