If anyone wants to see what I do with my nesting tunnels during the winter, I wrote a post with tips and photographs of the occupants (mason bees, wasps, Houdini flies). When possible, I included links to what they'll look like as adults. Post also has information on how to make your own insect hotel and where to buy them.

First reported in New York in 2011, kleptoparasitic Houdini flies from Europe have now been sighted in Washington (state), which probably means they are in multiple states. Please submit observations if you see them lurking around your premises. This is a photograph of an adult at my hotel in Pennsylvania (2019).

I have a Twitter thread if you'd like to learn more.

@clearwing_moth opened up a section of bamboo from a mason bee house and found two larvae inside. If you have any thoughts on what they might be, please check out her observation.

In case you missed it ... @cgritz in Maypearl, TX, has something rather strange going on at her bee/wasp hotel. On several photographs of Euodynerus megaera she's noticed exuviae in nearby holes. Please check out her photographs and leave a comment if you can provide any details.

In setting up this project I am hoping to foster some communication among iNaturalist users who have insect hotels. Observations might primarily document the most popular target guests, mason bees and their kin, but will also bring some deserved attention to solitary wasps that love holes just as much. More broadly, carefully observing insect houses for all guests (inquilines, parasitoids, etc.) can demonstrate hidden diversity in even highly urbanized settings. Thanks in advance for joining or for submitting observations. And please make yourself a hotel if you don't already have one. They make great gifts, too!