Homes for the winter

Cecropia moth cocoon

Here’s some of those photos I’ve had sitting around for a while, waiting for an opportunity to post about them. This first one I’ve had since January! I came across this interesting structure while out with Blackburnian during the Colour-coding Chickadees walk. I had no idea what it was at the time. It was already open when I came across it, and there was nothing in it. It resembled a cocoon, but I didn’t really know. Lots else to post about, so I never got around to looking it up.

Then in mid-February, Jennifer over at A Passion for Nature posted a cocoon she’d been seeing on some of her walks, and a couple days later she posted a follow-up about the cocoon’s occupant. Turns out, it’s the cocoon of a Cecropia Moth, one of the North American silk moths, a group of beautiful, giant moths whose caterpillars spin “silk” which they use to create their cocoons. Jennifer directs her readers to a rather amazing site that documents the life cycle of the moth from egg to adult (and now I’ll direct you there, too!). The site indicates that the moths overwinter as pupae, so the fact that this cocoon is split open likely suggests that it’s either last year’s case, or somebody/thing got to it before I did this winter.

Bagworm moth case, Psyche casta

This second one is also a moth, and I’ve also had it on hand since January. I knew right away what this one was when I saw it, from having browsed through the Moth Photographers Group website while identifying a few moths last fall. Of course, I couldn’t remember exactly which it was, just that I’d seen it on the pages, so I had to go back and scan through their many (very useful) pages all over again.

The case, which superficially reminds me of those made by caddisfly larvae, is made by a moth belonging to the group of “bagworm moths”. This one’s probably Psyche casta; the different species have different case styles, but I would assume some of them to be subtle. Like the caddisfly, the moth larvae tote this bundle of sticks around with them until it’s time to pupate, at which time they affix it to a solid surface for the winter. I found three of these all sitting in the window frames of my parents’ house. Two were between the panes of glass, but this third one was on the interior frame, which made it easier to photograph, but also meant it was exposed to spiderwebs, dust, pet hair, etc.

Wikipedia indicates that many bagworm moth females have vestigial wings, and sometimes never leave their cases, mating with males even while still inside. They die after mating, either having laid the eggs inside the case, or without having laid the eggs (so the larvae mature and emerge from the female’s body). The eggs are very hardy, and a bird that finds the case and eats it will pass the eggs through its digestive system intact, aiding in the spread of “new blood” from one area to another.

Praying mantis egg case

And this final case isn’t a moth or butterfly cocoon, but instead was created by a Praying Mantis. They started appearing late last fall, and I think I found five in total, four of them laid on the research station’s exterior walls. I didn’t know what this was at first, either, but I think one of the volunteers at the station pointed it out and identified it for me. They were still there, all of them, when I was back for the start of the spring season. When they were first laid they were a little gooey to touch; now they’re all quite hard.

I read somewhere that they’re always laid on the south side of the object they’re affixed to, which is actually true of the four on the station building. The one pictured here, however, found at the base of a metal signpost, was on the north side. I guess that one didn’t get the memo. Mantids are fairly common at the spit, which is pretty neat, since I never saw many growing up. Despite their slightly startling, ferocious appearance, they’re pretty tame to pick up and handle, not inclined to bite, which makes them great for showing to kids. Just like hatching a cocoon, you can bring these cases inside and set them up in a terrarium to hatch – or, if you don’t want to risk damaging the wild ones, you could order your own Praying Mantis Encounter from Discovery Channel’s store, and treat the kids (or yourself) to a neat experience watching them grow. Only available to the US, unfortunately, or I’d order one! :)