I had one of those “Hey! I know that!” moments earlier this week when, hiking through the woods on my snowshoes, I paused to check out a little bagworm case on the trunk of a young Trembling Aspen. It was complete coincidence – it’s not as if I don’t see lots of bagworm cases around, so why I stopped for that one, I don’t know – but in glancing the other way, at the aspen beside it, something else caught my eye. And I recognized it immediately. And was immediately excited for the recognition. (Naturally I didn’t have my camera, the one day in weeks I left it at the house, so I had to mark the tree and come back the next day with my macro lens).
Do you recognize it? I briefly mentioned something like it before here, when I posted my book review of Eiseman & Charney’s excellent work, Tracks & Sign of Insects. It reminded me of one of the photos on the cover of the book, and which I also posted a scan of the relevant page from inside.
Turns out it’s not quite the same thing. The one on the cover of the book is the cocoon of a spongillafly, a type of neuropteran (looks like a mini caddisfly) associated with freshwater sponges. But the spongillafly cocoons have a white inner cocoon that, even after they hatch and leave, remains behind. My lacy cocoon had no inner cocoon. Even besides that, the spongillafly outer cocoon is built in nearly hexagonal loops. In the one I found, the loops were more rectangular.
This was a key feature. Reading a bit more of the text, the authors say, “The bumelia webworm moth … spins a delicate, golden cocoon with a very coarse, rectangular mesh … Wockia asperipunctella, only recently discovered in Ontario, makes a similar cocoon on aspen and willow.”
Rectangular mesh – check! Found on aspen – check! Located in Ontario – check! Seems like a pretty good match to me!
Just to be sure, I posted it to BugGuide.net, and Charley Eiseman, one of the authors of the book who happens to frequently patrol BG generously helping out with IDs, agreed with me that this was the likely builder.
I haven’t ever seen the adult moth of Wockia asperipunctella, but it’s a micro, and unless the micros are particularly flashy or notable for some reason, I haven’t paid much attention to them. I’m still working on solidifying my macro identification. The species will be included in our field guide, though. Here’s one of the plate images we’ll be using. It has no official common name anywhere that I could find, but asperipunctella roughly translates to “shaggy-spotted” (and you can see why – the black spots have raised scales), so that’s what I named it: Shaggy-spotted Wockia. I had to resist really hard calling it a Wookie.
14 thoughts on “Lacy cocoon”
Awesome find! I followed the conversation on BugGuide as it was unfolding as well. When you first posted it there I dug out my copy of Charlie Eiseman’s book, too.
Wondering where on earth “they” came up with a name like Wockia (Woookie, indeed).
BugGuide’s a great resource, eh, Sara? Many neat discoveries and some fabulously knowledgable people!
There are some strange names out there. I think most have at least some basis in either Latin/Greek or are a tribute to a person.
What a fabulous post! I’ll be on the lookout for these tiny things at Hill-Stead. What a good eye you have, let alone memory. I aspire to it. Thank you as ever for the wonderful information and the enjoyable content.
Thanks, Diane! Good luck searching! I don’t know how far the species ranges, but even if you don’t notice this particular one, you might find other lattice cocoons.
Wow, you did good to even spot it, it’s so small!
Complete chance, Karen! Stopped at the right spot, looking at the right angle to see it in profile. I’m sure if I’d looked at it straight on I would’ve missed it. I was amazed at how tiny and delicate it was, too.
A correction: you called the spongillafly a dipteran here, but it’s a neuropteran. There are some nice photos of adults and larvae on BugGuide: http://bugguide.net/node/view/40303/bgimage
Great to see my book being used to solve these little mysteries!
Thank you, Charley! You know, I wrote that in to the post intending to go back and double-check it before I published it, but completely forgot (obviously). They look like mini caddisflies. The BugGuide page notes that they come to lights; I wonder if I’ve ever seen some and written them off as caddisflies?
I love your book! I have only a handful that get pulled off the shelf on a regular basis, and it’s one of them.
Nice find. I am hoping to come across the spongillafly cocoon since seeing them in Eiseman’s book. Amazing architecture!
Ted at Beetle in the Bush has also posted on some signs of insects – http://beetlesinthebush.wordpress.com/2011/01/13/diversity-in-tiger-beetle-larval-burrows/
They’re pretty impressive, Adrian.
Thanks for the link to Ted’s post. I’m way behind on my blog reading and have dozens to catch up on, so I hadn’t seen that yet. I’ll be paying attention for burrows of our Six-spotted come summer, I think…
An insecto-architectural marvel.
Indeed, Mthew! All the more so for its durability.
I thought you’d get a kick out of this, given your wookie comment: http://species.wikimedia.org/wiki/Wockia_chewbacca