Western Tiger Swallowtail

Subject: Furry Western Tiger Swallowtail
Location: Red Car Property, Silver Lake (Los Angeles)
March 9, 2015 12:28 am
Hi Daniel,
As you may have heard, we’re having a butterfly bonanza in Silver Lake this year. Today’s question is more about function than ID. Why do the Western Tiger Swallowtails have so much fur? It would seem not so aerodynamic . Photo attached was taken on the Red Car Property March 5, 2015. It was supper furry, as was the one I the week before in my backyard:
Both seemed to be sunning themselves in the morning sun on very warm days on broad leafed, non-native plants (wild geranium & nasturtium).
Signature: Diane E

Western Tiger Swallowtail
Western Tiger Swallowtail

Good Morning Diane,
The physical feature of “fur” on butterflies is not confined to Swallowtails, but since Swallowtails are so large, it is more easily noticed.  Alas, we don’t know why this trait has developed, nor do we know what purpose it serves.  We will post your image and hope one of our readers is able to enlighten us.

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