Delicate Cycnia Moth

Here's someone I forgot to mention when talking about the insects of milkweeds and dogbanes; it's the Delicate Cycnia Moth (aka Dogbane Tiger Moth). It appears that "cycnia" is pronounced like SICK-knee-uh. If that's something you're not going to remember, there's always the Dogbane Tiger Moth name available to you.

Though I don't see these guys a lot in the day, I'll sometimes see them. In flight you might be fooled into thinking they're the far more common Cabbage White butterfly, but if they sit still for you, you should be able to tell the difference. The Delicate Cycnia lacks the little black smudge marks on the wings, and has a slightly yellowish color on the wing edges.

As one of their names suggests, as caterpillars these moths eat dogbanes and sometimes milkweeds. This makes them poisonous, or at least foul-tasting. This provides them protection from bats, who would normally love to snack on a moth.

Their relationship with bats has been studied quite a bit. These are one of the moths that can emit an ultrasonic noise when they detect bats are targeting them with the bats' echolocation. Usually this will trigger the bat to look elsewhere for a meal. There are 2 main theories about what's going on:

  1. Interference: It's possible that the moth noise interferes with the bats' echolocation capabilities, and the bat knows it's not going to be able to locate this moth.
  2. Aposematism: It's possible that bats recognize from the ultrasonic signal that this moth is poisonous, and they decide not to eat it.

It's also possible that both interference and aposematism are at work here, with the moth simultaneously communicating that it's poisonous while also making it harder for a bat to find it.

August 20, 2021 at Duke Farms
Photo 157559113, (c) jpviolette, some rights reserved (CC BY-NC)



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