The arrival of September at our latitude marks the time when windows closed all summer can be opened to admit cool night air. As I opened the window on our guest room, I was startled to see a wad of cotton-like material tumble from the upper window frame (above, placed on the concrete driveway for imaging).
My initial anxiety was that some sort of insulation was coming loose, but the original location of the material (photo below) ruled out that possibility.
My attention was now drawn to the contents of the mass, which to my initial dismay revealed an insect pupa and a number of living larvae:
After searching several combinations of key words in Google Images, I found one entry that matched my experience. The brief explanation there was that the mass was the creation of a solitary bee.
Now I did feel bad, because my wife and I are great fans of solitary bees. But armed with that clue, it didn't take long to track down the answer:
Anthidium manicatum, commonly called the European wool carder bee, is a species of bee in the family Megachilidae, the leaf-cutter bees or mason bees.I don't know whether the larvae in the photo are bee-related or parasites.
They get the name 'carder' from their behaviour of scraping hair from leaves such as lamb's ears (Stachys byzantina)... They scrape the hairs from the leaves and carry them back to their nests bundled beneath their bodies. There it is used as a lining for their nest cavities. Females tend to build their nests at high locations.
Reposted from 2016 because this week I was wandering through the "gardening" section of our local Target store and found this:
The shelf tag erroneously said "butterfly house." The label on the product was slightly less inaccurate with "insect house." It is in fact a structure designed for solitary bees. There are online instructions for making these as a DIY project, but this one was nicely made and inexpensive. I'll hang it from a shepherd's crook near ground level in our garden and hope to see some of the tubes getting filled as the summer progresses.
Here is a photo of an equivalent bee-condo viewed in cross-section:
This one was made by drilling holes in a wood block (presumably with a removable flap so the curious home scientist could inspect the process and the season progressed).
If I remember, I'll try to post followup photos in the summer and autumn.
Updated May 2018 to show the bee "condo" installed in our back garden -
Helpful hint: A "shepherd's hook" (used for hanging flower baskets, bird feeders etc), when purchased from a home decor or gardening store can be somewhat pricey. I went instead to our local farm supply store and picked up the "pigtail" post shown in the photo (used on farms for stringing electric fences around fields) for about $2. An added advantage is the little S-shaped part at the bottom which grips the post for stepping it into the ground and digs into the ground to provide 2-point stability for the post.
Well, back to the drawing board. After a week of drenching rains, the "bee condo" was in multiple pieces. I don't think I can blame raccoons, because there was no honey or larvae in it yet. Wind might have banged it around a bit, judging from the current position, but I rather suspect this was assembled using water-soluble glue.
It was cheap. You get what you pay for.
Fortunately I have several rolls of duct tape in the garage.