There is a huge wave of enthusiasm for bee hotels and that’s totally understandable – we all want to help native bees that are facing incredible challenges. A landscape with lots of pollinator-friendly flowers is an important forage buffet, but a landscape that also provide areas for pollinators to nest, shelter and overwinter – now that is a pollinator garden. In my parlance, that’s a Pollinator Victory Garden (if it’s pesticide-free and follows the PVG fundamentals).
But, is a bee hotel the best approach for supporting native bees?
Keep in mind that approximately 70% of the native bee species in North America are ground-nesters. For these ground-nesting bees, a bee hotel is of no use. Most of these bee species need a bare patch of soil in a sunny area, with soil that is workable – not too much sand or too much clay. Encourage and protect the areas in your landscape where you see ground-nesting bees already, and consider creating new areas to support even more of these bees.
The other 30% of our native bees in North America are cavity-nesters and they seek out a wide range of cavities, depending on the species of bee. Pithy plant stems, old beetle burrows in dead or dying trees, decaying logs, abandoned mouse holes, gaps in stone walls, brush piles and even gaps at the base of native bunch grasses, are all potential nesting habitats for cavity-nesting bees. Certain bee species will gravitate to particular habitat – and they all matter. Encourage these natural habitats in your landscape, and avoid disturbing them.
So what about bee hotels? Spoiler alert – I recommend focusing on natural habitat first. Consider a bee hotel as a supplement to, not a replacement for, natural habitat. Even many small urban landscapes can provide some degree of natural habitat, but keeping a dead tree or a brush pile may not be a reality for every landscape.
It may be that Mother Nature really does know best. It’s not yet clear whether cavity-nesting native bees will use, or have a net benefit from, bee hotels. A 3-year research study on bee hotels in Toronto puts it this way: “Campaigns to ‘save the bees’ often promote these devices (bee hotels) despite the absence of data indicating they have a positive effect.”
The Toronto researchers found that native wasps were significantly more abundant in bee hotels than native bees. In this study, native wasps occupied 75% of the 600 bee hotels observed. Native wasps have lots of ecological value, but their study suggests that “bee hotels” may actually be more “wasp hotels.” For the cavity-nesting bees that did show up in this study, nonnative bees were more prevalent than native bees.
Another concern is that parasitism on bees is higher in bee hotels than in natural cavities. The congestion of a bee hotel makes for an easier target for predators.
My conclusion – we may be putting the emPHAsis on the wrong SYLlaable given the current obsession with bee hotels. We don’t yet have enough research to guide us. I believe that the first priority should be on encouraging and protecting natural bee habitat in our landscapes for both cavity-nesting and ground-nesting bees. If you’d like to give a bee hotel a try, do it as a second step, and understand the potential limitations. Do some research on the best practices for building or buying bee hotels (they are not all the same) and learn how to manage them. Michigan State University has an excellent bulletin on making and managing bee hotels and the Xerces Society has a great fact sheet on nests for native bees.
Spread the buzz! Pick up a copy of my new book, The Pollinator Victory Garden: Win the War on Pollinator Decline with Ecological Gardening.
From Kim Eierman at EcoBeneficial!