How do you know it’s a moth?

Chickweed Geometer Moth, Hillman State Park, August 2011 (photo by Dianne Machesney)

24 August 2011:

Most moths are nocturnal but Dianne Machesney found this Chickweed Geometer Moth during the day at Hillman State Park.

How can you tell it’s a moth?

First clue: Is it flying?  Moths fly at night(*), butterflies fly during the day.

Second clue: How does it hold its wings when resting?  Moths open their wings flat (as above) or fold them tightly flat over their backs. Butterflies hold their wings upright, clapped shut above their bodies(**). Click here to see an illustration of these postures.

Third and Best Clue: Look at its antennae.  Moths have fuzzy antennae with many tiny branches.  Butterflies have smooth antennae with little knobs at the end.

Of course there are exceptions.  The Chickweed Geometer moth flies during the day (* erf!).  However, the males have very fuzzy antennae.  You can tell this moth is a boy.

For more information on the differences between moths and butterflies, see a summary at Live Science or this detailed discussion at Wikipedia.

(photo by Dianne Machesney)

(**) p.s. Skippers are butterflies but their resting posture is halfway between that of a typical moth or butterfly.

5 thoughts on “How do you know it’s a moth?

  1. We’ve observed a moth over the past two summers that we first thought was a hummingbird, but it’s indeed a moth! I was able to determine that it’s some type of hawk or sphynx moth, but can’t narrow it down.
    Do you know anything about which species are in our area?

  2. I have a picture of an insect that looks like a moth. How do I identify it? It looks like it has camouflage that would make it blend in well against a tree.
    Thank you for your help.

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