Wednesday, July 2, 2014

Squash Vine Borer Moth

In my vegetable garden, I have a large clump of Butterfly Weed that brings in a wonderful collection of nectar consuming insects.  I had my face tucked in close to the bright orange blooms when a wasp-like insect nearly grazed the tip of my nose.

I pulled my face back a bit and watched the little flier spiral its way into a landing on one of the flower clusters.  At rest, this insect certainly displayed some hymenopteran qualities, but it was certainly no wasp.

Closer examination shows it to be a moth, a Squash Vine Borer Moth to be exact.  This is one of the few day flying moths.  It is also a wasp mimic, meaning that the physical appearance of the moth has a resemblance to a wasp.  This mimicry affords the moth some protection from predators that would avoid tangling with a stinging wasp.

A search of the flowers revealed several of the moths mixed in with the crowd of truly stinging insects.

The hind wings are clear, which emphasizes the dark forewings.  When outstretched, the wings resemble the raised forewings of an angry wasp.  The hind legs bear large tufts of dark reddish-orange hairs.  When in flight, the moth carries the legs below the body and it looks very much like a wasp carrying a caterpillar.

The antennae with their curled tips even look like the antennae of male polistes wasps.  This is a very interesting moth in terms of both form and behavior.  The name Squash Vine Borer says all that most people need to know about this moth.  The larvae live their lives inside the stems of squash vines and their relatives, ultimately bringing death to the plants.  Because of this, most people’s interest in the moth doesn’t stray far from how it can be eliminated.

There’s a good reason why so many of these moths were visiting this particular patch of Butterfly Weed.  There are some nice summer squash vines growing just a few feet away.  I may lose a vine or two to the moths, but it’s not really a hardship.  I’ll trade a couple of vines for the experience of watching the adult moths.  Besides, I love to eat fresh squash and start a few new plants every couple of weeks right into summer.  The adult moths are only around for a short time, so they won’t infest my later plantings.  I’ve never had them lay eggs on all of my vines and there has never been a summer when I couldn’t go out at any time and pick some fresh squash.

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