Monday, September 8, 2014

Sleepy orange butterfly color variation is confusing‏

When you are trying to learn how to identify the butterflies, variation among one species can be very confusing.  For the sulphur butterflies, all those yellow and orange ones, this difficulty is magnified if a single species varies in color.

Books report a seasonal variation in the color of the sleepy orange butterfly, found from southern PA to FL, from bright yellow-orange in summer to a dull winter form.

Here on our VA farm even in summer we have considerable variation between the classic bright form and a much duller color form.  Since this is a butterfly that flies low to the ground and often alights on ground vegetation, this color difference may have some significance in terms of camouflage and in breeding/attracting a mate.  Perhaps the brighter form is more successful in mating but gets eaten more often by predators?

For example here are butterflies photographed between Sept. 1-3.  Compare the bright form on green grass and the dull form against a mottled leaf.

By the way plant Cassias/sennas as a food plant for this beautiful insect.  So is it coincidental that a yellow butterfly feeds on a yellow flowered plant?

Bill Dunson

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