Beware the Wasp Moth

I saw this insect on a Swamp Milkweed plant today and thought at first it was a beetle.

No, it doesn’t have the hard outer elytra covering its wings that beetles have.  So maybe it’s a wasp.  Those sort of look like wasp wings.

But look at that hairy body, hairy legs, and long antennae.  And the clincher to figuring out that it’s a moth is that long proboscis it is using to probe the milkweed flowers.  Aha — it’s a wasp moth.

And apparently it has clear wings, as you can see it hovering in front of the milkweed flower that was blowing furiously in the wind.  This was quite a challenge to get the insect in focus while it was waving around in the wind.

Search clear wing wasp moth on Google and you’ll find that this is the dreaded squash vine borer, (Melittia cucurbitae) a major pest of the squash, pumpkin, and cucumber plants.  It is a member of the Sesiidae family of clearwing moths, many of which have this same wasp or hornet coloration, a mimickry which apparently protects them well enough to be active in the daytime.   The adult is harmless enough except that it bores a hole in the base of a squash (or cucumber plant), lays an egg there, and the larva then proceeds to eat out the interior of the vine, usually killing the plant.  This behavior is also typical of other species of clearwing moths.  Preventative measures include wrapping duct tape or nylon stockings around the base of each vine or killing the larvae within the stem by poking the stem with a sharp object, like a stiff wire.   I’m glad I don’t grow pumpkins for a living.

Rather handsome insect.  Too bad it’s a pest.

6 thoughts on “Beware the Wasp Moth

  1. Pingback: Gardening woes | Back Yard Biology

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  3. Found one of these in our school butterfly garden and was trying to identify it. I too thought it was a wasp at first but guessed that it was a moth after looking at my pictures. Thanks for the great pictures and interesting background!

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