If You See This Weird Cocoon Thing in Montana, Don’t Smash It

Facebook can get pretty annoying. Sometimes I want to delete the app and my account soooo badly. I feel like if social media disappeared tomorrow, perhaps the world would be a slightly better place.

For my line of work, however, it's a bit of a necessity. And despite all the targeted ads, divisive political arguments, AI slop, and doom-scrolling in the Comments, there are a few local pages I like to follow. One of them is Ask Billings.

The page is relatively drama and troll-free and is basically exactly what it sounds like. Questions about Billings. "What was this building? Where can I find ______ in Billings? Who has the best ______ in Billings?" You get the idea.

What is this strange thing?

Recently, someone posted a picture (seen above), wondering what the item in the photo is. My initial guess was some kind of dauber-type bug nest. I was close, but wrong. The thing pictured is a cocoon-like bundle of praying mantis eggs. The internet says,

Praying mantis eggs are enclosed in a protective, foamy, Styrofoam-like casing known as an ootheca (plural: oothecae). These cases are laid by the female in late summer or fall on twigs or stems to protect the developing nymphs through winter.

Don't mess with the ootheca.

You shouldn't remove the egg sacs unless you have an issue with an interesting, cute, and beneficial insect. Praying mantises (alternate plural: mantids or mantes) have a ravenous appetite for (mostly) bad bugs in your garden.

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According to the Green Bay Botanical Center, praying mantises will devour "mosquitoes, mites, moths, wasps, flies, cockroaches, and many more insects." They don't seem to discriminate, though... they'll also eat butterflies, bees, and spiders; larger mantises have been known to eat small frogs or minnows. Who knew?

Are praying mantises becoming more common in Montana?

I've lived here since 1988, and I don't recall seeing praying mantises in our yard or garden very often - if ever - until the last decade or so. We now see a few each summer here in the Billings area.

I'll typically find one in my garden plot, but sometimes we'll see one on the window screens. They're usually bright green, and I've never seen them get bigger than maybe 4 - 5 inches long.

My kids love watching them, and I like seeing them in my garden, eating spider mites, aphids, and whatever else they enjoy. They can bite humans, but it's reportedly rare, and when handled gently, you should be fine.

If you do get nipped, praying mantises are not venomous and rarely break the skin. Like the dentist says, "it's just a little pinch."