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Here are two different butterfly individuals of different species in northern Taiwan whose wings had ragged edges.

The whitish one was pretty lethargic and just wanted to stay in the grass and be left alone. The dark one with four purple spots (two per wing) on the other hand was flying from leaf to leaf, and even tried to land on my green cellphone case. He also seemed to just want to rest, rather than look for flowers.

So my first suspicion is that these (like me) were nearing the end of their life and just wanted to take it easy.

In both cases I noticed that the back edges of their wings were ragged. I'd never seen that before. Do butterfly wings normally wear out like this? Could it be camouflage (straight abrupt edges might be easier to discern when resting) or perhaps a fungal infection of the wings?


Individual #1 April 7, 2024 in northern Taiwan:

old? butterfly in northern Taiwan, April 7, 2024

old? butterfly in northern Taiwan, April 7, 2024


Individual #2 April 21, 2024 in northern Taiwan:

old? butterfly in northern Taiwan, April 21, 2024

old? butterfly in northern Taiwan, April 21, 2024

old? butterfly in northern Taiwan, April 21, 2024

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In both these cases, the butterflies are old (relatively speaking) and worn. Usually, adult butterlies only live during a specific season (which usually can last weeks to months) or with several generations during a season. It is then common to see this kind of apperance on individuals at the end of the seasin, when they are close to the end of their normal life span. They are often ragged, have lost most of their wing scales, can have pieces of their wings missing (from e.g. attempted bird attacks), and they often have quite faded colours compared to newly hatched specimens. That the wing veins are sticking out (as in your pictures) is also normal. In general, most butterflies can fly quite well with surprisingly large portions of their wings missing.

A "ragged" apperance can sometimes also be found as part of camouflage or mimicry, but this is not the case here. However, some quite normal examples (i.e. not the most extremt examples) of this can be seen in these pictures. Here you can see relatively jagged edges and wing appendages, but still a somewhat more "clean" apparence than in your pictures.

Polygonia c-album from wikipedia Polygonia c-album (pic from wikipedia), showing example of ragged camouflage

Thecla betulae from the Swedish species information centre, artdatabanken.se Thecla betulae (pic from the Swedish species information centre), with example of mimicry/diversion (false antenna, indicating location of the head).

As a sidenote, I think the latter of your butterlies is Hypolimnas bolina, which is relatively common in south east asia.

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    $\begingroup$ Oh wow, thanks for the beautiful examples of ragged camouflage! Also, thanks for Hypolimnas bolina, yes it certainly looks like a match for the male. So now I need to go back there and start looking for a female - I'd love to have photos of both. $\endgroup$
    – uhoh
    May 2 at 15:05

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