What's That Bug? does not endorse extermination

Mourning Cloak Butterfly
Hi WTB,
I just wanted to share with you and all of us “bug-sleuths” my recent discovery. About a two months ago I began seeing thousands of little black turds on my back porch under my chinese elm tree. At first I was very concerned thinking that I may have an infested tree. I suspected the turds were non mammalian or avian due to the shape of the extrusion. They were not round, but slightly squared and short in length. My suspicions were proven correct when among the turds one morning were a dried up caterpillar, too emaciated to get a good identification. The identification came about a week later when the caterpillars in my tree were on the move. I spotted ten or so caterpillars that were spiny, charcoal grey with red markings that were slightly diamond shape along the back (see the picture).

They had apparently dropped from the tree and were making their way up the walls of my house in order to find a place to chrysalize. Once they found their chosen place, they attached themselves and spun a light grey chrysalis. One thing I noticed was that part of the caterpillar actually became discarded in the process. I could not tell if the head or the tail of the caterpillar lost out. Nonetheless, nature took its course, and one morning, I had the wonderful opportunity to photograph one of the butterflies just born, drying its wings in the sun. While it is not a strikingly colorful specimen, it is nonetheless a wonderful part of my backyard environment. Enjoy.
Bob K
Sunny San Diego, CA

Hi Bob,
What a wonderful account of Mourning Cloak metamorphosis. During each stage of metamorphosis, the individual loses its exoskeleton, hence the discarded chrysalis skin in the background of your butterfly image. Mourning Cloaks are native to California, and before the introduction of the Chinese Elm, a favorite host tree, they fed on riparian willows that grow near stream beds and rivers. This is a wide ranging species that is found throughout North America and Europe in the Northern hemisphere.

What's That Bug? does not endorse extermination

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