Saturday, July 24, 2010

Crambid Moths at My Door

Moths in the family Crambidae are usually tiny. Their long, projecting mouth parts give the appearance of a snout, so members of the family are sometimes called "snout moths." While resting, they roll their wings around their body so that their bodies appear angular. This makes them inconspicuous when they rest on stems or leaves. The Crambid moths in this post came to the back door the last time I left the porchlight on for them.

The two photos above are both of the same moth, which I think is a Bluegrass Webworm Moth (Parapediasia teterrella). The smoothly curving subterminal line and toothed post median line are distinctive. These moths are found in grasses; you may flush them (or their close relatives) as you walk through a grassy field or lawn. According to BugGuide, the larvae feed mainly on bluegrass and tall fescue.

The next moth is a Lucerne Moth (Nomophila nearctica). This is a common species that I have posted here before. This individual is more darkly marked than the one I found at Davidson Mill Pond Park.

The next moth is a Changeable Grass-veneer (Fissicrambus mutabilis). These moths are found in lawns and other grassy places; their larvae feed on grasses. Above you can get a close look at the mouthparts (palps) that form its snout.

This is the same moth perched on the side of an empty film container that I use for collecting specimens. I refrigerate any that I capture and then release them once I have photographed them. This angle gives a better view of the key markings, the post median and subterminal lines. The photo also shows a characteristic posture of grass-veneer moths; often they sit with their heads angled down and the tips of their wings angled up. I am not sure if this provides better camouflage or if it helps the moth take flight faster.

I think that this last moth may also be a Changeable Grass-veneer, though it lacks evidence of a subterminal line. The other related species do not fit quite as well.