Jar, I'm not convinced that the green butterflies on the foliage are the same species as the yellow one in your other photograph. As Panda already pointed out there are some differences between the two, of which the wing form is the most prominent. The trailing edges of the yellow butterfly's wings are waning gibbous, like the moon is between full moon and third quarter. The green one has wing edges in the shape of a crescent.
Did you take the picture of the yellow butterfly yourself, or is it a stock picture?
Also, in the picture of the green butterfly most of the ambient light is reflected from the white trellis, so the explanation for the green colour having to do with the foliage seems a bit farfetched to me. Perhaps the butterflies' wings are yellow on top and green underneath?
"Ignorance more frequently begets confidence than does knowledge: it is those who know little, not those who know much, who so positively assert that this or that problem will never be solved by science." - Charles Darwin.
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