Sunday, April 22, 2012

Knee Deep in Red Admirals and the "Savage" Mourning Cloak Butterflies

Red Admiral

An astounding number of Red Admiral Butterflies continue filter up from the south where they overwinter. Right now they are the most common butterfly to be found at the Nature Preserve –and just about anywhere else for that matter. With the species’ host plants (plants in the nettle family) just barely emerging from the ground, it seems like they may in in fact be all dressed up with nowhere to go.  I suspect that this phenomenon is yet another of this year’s many examples of nature being “out of sync”. However, I think that it is safe to assume that the mild winter has led to a much greater survival rate in Butterflies. Unlike the Admiral, many butterflies spend their winter with us in some form or other –as adults, chrysalises or caterpillars. In a normal winter many more of them would have perished.  Of course, not just butterflies survived the winter, but many other kinds of insects as well –including many species that are butterfly predators. Most of the butterflies’ insect predators attack them while they are still in the caterpillar stage. Ichneumons are a large family of parasitic wasps that lay their eggs inside the bodies of living caterpillars. So instead of the caterpillar developing into a butterfly, their flesh is commandeered to feed a wasp larva growing inside them. So the abundance of butterflies in this pre-season period may be followed by a dearth of butterflies later on. I sincerely hope this isn’t the case.

Mourning Cloak Butterfly
Just lately, Mourning Cloak butterflies have been pretty common in the forest. They are a very regal looking species with iridescent dark brown upper wings. The wings have a golden trimmed border and a row of blue spots. The closed wings are the color of charcoal and appear rough textured, which makes the species a convincing dead-leaf mimic.
Jagged edged wings help the Cloak to resemble a leaf
One doesn’t usually associate butterflies with aggressive behavior, but our Mourning Cloak Butterflies could be considered good candidates for counseling. The male Cloak will claim a piece of territory and any other male that passes through will be attacked and perused. The 2 brawling butterflies often ascend straight up into the tree tops before breaking apart. The stranger goes on his way and the defender comes back to perch in some prominent position where he will be ready to quickly spot the next intruder or potential mate.  Neither combatant usually sustains much damage from these encounters; butterflies after all, are not exactly armed to the teeth. Honestly, what can they do ...put their proboscis in someone’s eye? Occasionally, a particularly macho Mourning Cloak will try to chase me out of his territory, which is always entertaining. Sometimes, just to make him feel good, I’ll run off yelling “Help!”
Mourning Cloak caterpillar all decked out with spikes and red spots
As caterpillars, Mourning Cloaks literally look like they are dressed to kill. They have bright red spots along their backs, and red pro-legs on their underside. Bright colors like these often indicate toxicity to their potential predators. If that’s not enough, these caterpillars also have rows of long intimidating spikes running all along their backs and sides. All in all, they don’t look very appetizing –and that’s the whole idea.

Mourning Cloak feeding on willow leaves
What’s most interesting about this is that the male Mourning Cloak so often chooses territories that are far from the where the species main food plants grow. In the case of the Cloak, their food plants are for the most part trees in the willow family, which are not typically found in inner forest situations. But indeed, that’s where the Cloaks look for mates and seek shelter from the elements.
Sunning himself on a rock to warm up
The lifestyle of the Mourning Cloak seems to work well for the species. The fact that their population remains relatively stable from year to year is no mean feat in the world of butterflies. They are also the longest lived of our butterflies –sometimes surviving for an entire year. This of course, includes the winter months in which they are alive but dormant.

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