Tag Archives: native

Mason bee hotel construction

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I built a hotel for mason bees, leafcutting bees, and hole-nesting parasitic wasps and thought I’d post pics in case anybody is looking for tips on how to make one. Overall dimensions are 12″ (W) x 25″ (H) x 11″ (D) and situated facing southeast so that it catches some good morning sun (the bees like that). I gave it three levels so that I can fuss with one level without disrupting all the tenants (bees hate that), plus used dado joints give the whole structure some stability when fully loaded. The hotel is elevated to 4 feet on a 4 x 4″ post so that I can easily take photographs without stooping.

Mason bee hotel

I also have a piece of galvanized hardware cloth that can be attached (pic below), after all the holes are filled, to keep woodpeckers away. The wire is held by six neodymium magnets glued into small insets on each side. I’ll probably redo it with larger-hole chicken wire, and make it project farther away from the surface. The back of the hotel is a slab of 2×10. To attach the hotel to a post I used a small piece of wood that is first attached to the post, then attached to bottom of the house via four screws (shown below). Everything is just scrap wood from some dismantled cedar planters. Below are some pics:

  • Wire cloth protects bee larvae from woodpeckers
    Screen for birds
  • Back of mason bee house
    Back of hotel
  • Mounting plate for mason bee house
    Attachment plate
  • Drilling holes for mason bee inserts
    7″ logs with 6″ holes
  • 7" logs for mason bee house
    Logs with holes

Hole diameters

There are hundreds of different bee (Megachilidae) and wasp species that nest in holes, and all have slightly different preferences for wood type, hole diameter, and depth, so I’ve offered them a variety of accommodations in reeds, logs, and milled lumber, all cut into 7-inch lengths. The reeds are from Phragmites, and each section is cut so that the end has a node, leaving approximately 6 1/2 inches of usable tube. Logs and blocks are drilled with variable sizes of bits. The large log on bottom right also has a mix of 7/16-in and 1/8-in holes, some of which are already filled up (with mixture of nectar, mud, pebbles). Directly above the large log are two smaller ones that show how you can insert 6-in paper tubes into holes. At the end of the season you can easy pull those tubes out and transfer them to a protected location or refrigerator to overwinter. The other advantage of these disposable paper tubes is that you can easily unwind them to collect, study, and clean the pupae. The other paper tube is just a drinking straw I found on Amazon. These tubes will probably not be used this summer but I have them there just in case (the tubes are used by Spring mason bees and my house went up a bit too late this spring to attract any, I think). Finally, I have a few large-bore holes up in the attic space just in case that might appeal to a larger bee or wasp, though I probably won’t get a taker.

At the end of the season I’m going to gather up all the wood and reeds and place them in a protected location until next year. I’ll probably end up building a hatching box. After emergence ends I’ll either clean out the wood for reuse or throw it out. You need to do one or the other or risk causing diseases, mites, and parasitoids to build up in your bee house. To give you a visual on one risk, here’s a photo of a mason bee loaded up with phoretic mites. See also the Maclvor and Packer 2015 article, below.

Design tips

  1. For larger hole sizes you want, ideally, 6 inches of depth. Shorter (4″) tunnels would be OK but can result in a male-biased brood sex ratios. If you want to encourage population growth, encouraging females is important.
  2. To keep everything dry on something this tall you need a generous roof overhang. Mine extends 5 inches beyond the front of the shelf, plus the wood sections and reeds are set back from that by another inch or so. If you have a shorter house you can have a smaller roof.
  3. Burning the front of the wood allows bees to more easily find their holes, plus the darker surface causes the wood to heat up faster in the morning sun.
  4. Don’t use treated lumber or fresh cedar. Kills the larvae, apparently, or at least that’s the recommendation on the internet.
  5. Pine is fine but I think harder wood is preferable because the drilled holes are smoother.

My goals for building this house are mainly for edutainment (please join my iNaturalist project if you’re interested) but a bonus would be better pollination of my kiwi vine and strawberries. But that’s not a guaranteed because many solitary bees are oligolectic (collect pollen from only certain species of plants), and I’m not sure which species specialize on Actinidia and Frageria. I’m looking forward to next year when I can put out the blocks for (larger) spring mason bees, which I think are good for early strawberry pollination.

UPDATE: New blocks for 2019

Here’s a photograph of the fresh nesting accommodations I installed in the above hotel. Blocks have a variety of hole diameters to accommodate a variety of bee and wasp species: 3/16″, 5/16″, 5/8″, and 12mm. Hipster add-on apartment is for smaller Hymenopterans and is made from a Saint Benjamin Brewing Little White Lies IPA (design by Kathryn Moran) can packed with 5 1/2″ sections of swamp milkweed and wild begamot.

Three-level bee and wasp hotel

Further reading

Instragramming invasive species in Hawai’i

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During my recent trip to Hawai’i I got to wondering how conservation organizations use Instagram to educate the public about invasive species. A quick search pulled up several groups that seem involved, at least occasionally, and I’ll list here just in case you want to follow them (# followers in parentheses):

hawaii-invasive-species-instagramPart of my reason for wasting time on the above was because when I posted a photograph of an introduced frog, I wasn’t sure if anyone on Instagram might care. Potentially, there might be a group or two that might want to be mentioned, in the off chance that a species hadn’t been noticed at that particular location. Not being a native (I was a baby when I lived there), I had no idea which groups to tag, though, so all I did was add some hashtags for the species name as well as #invasive #introduced #nonnative … with the hope that somebody might find it useful someday (unlikely). But the process got me wondering how groups use Instagram to get the word out on how to control invasives. Here are some thoughts on how to do it, with apologies to the groups who are already doing it:

  1. To build buzz about your organization and its goals, repost images of others that show the species you are trying to control. People love to have their images reposted or their accounts mentioned. You can find these images by following people (duh), or by searching Google for Instagram photos with particular keywords (e.g., site:instagram.com coqui kauai). The routine is just this: ask them if it would be OK to be reposted/featured … and then give them credit by including Instagram handle (i.e., don’t just give the photographer’s name).
  2. If you don’t want to feature other people’s images, at least patrol other people’s posts that relate to invasive species, endemics, restoration, etc. For example, if somebody posts an adorable photograph of a small frog and says, “Love this little guy; going to send to my uncle on Kauai for his birthday!” … you can urge them not to do that. Or, when somebody posts about clearing invasives from property, you can say thanks (and perhaps invite them to a volunteer day if you’re group is local). And it’s not just people making posts about invasives … many companies are active in promoting pono and have thousands of active followers (@southmauispearfishing, e.g., has *dozens* of posts about invasive roi and what to do about them). The more you interact by favoriting and commenting, the more people on a particular island will see your organization’s work as important and worth supporting.
  3. If your organization has volunteer work days, add an “Instagram name” column to your sign-in sheet. Then mention each person when you post photos from the event (you should do that!). People love to be publicly thanked. Example. Another example.
  4. In your bio and in your posts, remind folks to tag their own images with #invasive #hawaii (or whatever) and species name so that the posts can help educate their followers. Example. Example. You can also dream up custom hashtags such as #hawaiiinvasive if you want (that’s from @kauaiisc, by the way).
  5. When you make presentations about invasives at local schools, show your Instragram handle at start and end. Young adults increasingly don’t care about your web site, your twitter feed, or your phone number but you might get them to follow on Instagram.
  6. Award prizes to people reporting or posting certain kinds of images. People love contests. For example, send some swag to person who posts best selfie with gold dust day gecko (example).
  7. If you have a Facebook page, add a tab for your Instagram feed. It’s easy. You should also automatically add your Instagram posts to your timeline.
  8. If you include a phone number in your bio for reporting a particular species, include an area code in case clueless tourists see call to action. Repeat this number in posts, too … because somebody might not bother to visit your actual home page.
  9. Check Instagram regularly to see whether anyone has posted an image of a species of special concern. For example, you can run a search for “site:instagram.com snake hawaii” to patrol for snake sightings (the search results are mainly Hawaiian shirts with snakes). There used to be several ways to automate such Instagram searches and receive emails … but Instagram blocked them.
  10. If your organization doesn’t have an Instagram account, fix that.