Common Buckeye

I got a pretty good picture of this Common Buckeye last September.

Depending on the year, I see these butterflies somewhere between "wow I haven't seen a Common Buckeye in a while" and "huh there's another Common Buckeye". I think I see them the most on sunny, grassy trails. Because they seem to like this habitat, I sometimes find myself inadvertently herding them up the trail; as I get closer, they fly further up the trail to get away from me. (This can happen with other butterflies and birds too.)

These butterflies have very prominent eyespots, including 1 very large pair on the top of their wings. It's not completely understood why they have eyespots. Generally they make a butterfly more conspicuous, which potentially makes it easier for predators to find them. Some theories:

  1. The classic explanation is that a predator sees the eyespots and mistakenly believes they're seeing the face of a much larger animal, causing the predator to break off its attack.
  2. The same article also discussing the idea that maybe predators actually attack the eyespots themselves. While not ideal, an attack on a wing is probably going to be more survivable than an attack on the head, thorax, or abdomen.
  3. This article suggests that the eyespots are due to aposematism, more like the bright orange or red coloring of many insects that tell a predator that they're poisonous. While the Common Buckeye isn't considered especially poisonous, insects aren't above displays consistent with being poisonous to ward off attacks.
  4. This cartoon has a novel explanation. Perhaps eyespots allow a butterfly to appear to be listening to a boring friend while actually engaging in more enjoyable activities (though admittedly I've never photographed a butterfly playing with dinosaur toys).

September 8, 2022 at Fairview Farm
Photo 248393747, (c) jpviolette, some rights reserved (CC BY-NC)


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