Friday, April 20, 2012

Ugly caterpillar = beautiful butterfly

One of the earliest woody plants to bloom in the east is the downy serviceberry, Amelanchier arborea. The  still bare treelets are festooned with spindly white blossoms in March, providing jots of color to woods that have yet to green. By now, the leaves are expanding, as above, and the leaves are blanketed in soft whitish pubescence. The hairs of the petioles are long and silky - sericeous, in botanicospeak.

I recently was able to spend some time afield with photographer Marcia Rubin, who works amazing magic with a Panasonic, and found that she also has sharp eyes. She drew my attention to a strange linear lump on a serviceberry in a woodland understory, and I was delighted to see what she had found.

It was a caterpillar, and not a rare one judging by all of the adult butterflies one sees flying about, all of which went through this stage. Nonetheless, it was a "life" caterpillar for me, and I was excited to finally turn my lens to one.

This is the larva of the red-spotted purple, Limenitis arthemis, and it is a masterful mimic of a bird dropping. I noticed that this one, when it apparently sensed that it had been noticed, froze tight. If one wasn't hip to the ways of bird-dropping mimic caterpillars, it'd be hard to recognize it for what it was. And by nearly any reckoning, a red-spotted purple caterpillar in repose is a very unpalatable looking lump.

Looking like a bird dropping is not such a bad thing. For most of the legions of caterpillars that are munching their way through our woodlands, birds are Public Enemy #1. But what bird wants to eat its own feces? Apparently, not many. So, by the always miraculous fits and spurts of Darwinian evolution, the red-spotted purple caterpillar and a few others in these parts have become like tubular bags of gooey feces. Another great example of a feces-pillar is the closely related viceroy, Limenitis archippus. Although the adults of this species little resemble those of the red-spotted purple, their caterpillars are remarkably similar. I blogged about a viceroy caterpillar, HERE.

Gross as this caterpillar may appear, I found it quite pleasing and took many photos. Caterpillars are an endless source of fascination on multiple fronts, and wonderful photographic subjects. Red-spotted purple caterpillars are reported to consume members of the rose family, apparently especially cherry (Prunus species). Like their close relative the viceroy, they'll also eat members of the poplar family (Salicaceae). But I did not know the cats ate serviceberry (which is in the rose family), so this knowledge may help me to find more of these interesting caterpillars in the future.

In a seeming paradox, that "ugly" caterpillar eventually morphs into one of our showiest butterflies. I photographed this mating pair of red-spotted purples in Washington County, Ohio, in 2010. The female hopefully went on to lay eggs, which would have eventually hatched into the bizarre caterpillar that we viewed in the previous photos.

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1 comment:

HernĂ¡n Tolosa said...

Beautiful insect, and marvelous mimicry. In my town I´ve found some insects larvae that looks like birds feci, but I don´t know they was lepidoptera or not