Warning Colors

I thought I understood well how warning colors function in nature. It makes perfect sense to me that a blue jay – new to the world – would sample a monarch butterfly. And that after vomiting and feeling quite terrible, he would choose not to eat any more of those orange and black-striped critters. I understand that the blue jay’s experience didn’t help the individual monarch whom he ate, but does benefit the monarch’s relatives within the jay’s territory.

It is also easy to see how a bobcat might approach a skunk, have a negative experience, and learn from it. In fact, I can find innumerable examples of how warningly colored animals teach predators a lesson they will not likely forget.

But what about that coral snake? One can’t learn every lesson first-hand. If a coyote tries to eat a coral snake, it may not survive the experience. Who would that be a lesson to? No one. Unless you want to try to convince me that the coyote had an audience, and that the onlooker learned to avoid coral snakes vicariously.

In The Birder’s Bug Book, Waldbauer speculates that it is possible that the coral snake actually mimics some other, less venomous snake. He supposes that the coyote encounters the other red, yellow, and black snake, and is assaulted with some mild venom. By the time he sees a coral snake, he knows to avoid the aposematic colors.

That’s a thought.

But what is that other snake? This snake would have to be nearly every place the coral snake is…from North Carolina to Argentina. There are 52 kinds of snakes in Louisiana. There are 5 venomous snakes besides the coral snake: pygmy rattlesnake, copperhead, cottonmouth, timber rattlesnake, and eastern diamond-backed rattlesnake. None of these contestants could win a coral snake look-alike contest.

So here’s what I think: Snake-eaters don’t learn to avoid red, black, and yellow rings. They are born with the instinct to avoid those colors. Add this behavior to hundreds of others that we already accept as instinctual (from how sea turtles get back to the same beaches where they started their lives to lay their eggs, to how my dog always makes three circles before lying down), and doesn’t it just make sense?



http://links.jstor.org/sici?sici=0003-0031(198004)103%3A2%3C346%3ARONTBT%3E2.0.CO%3B2-I



http://www.amazon.com/Birders-Bug-Book-Gilbert-Waldbauer/dp/0674002067

Host Plants

I found this caterpillar on the Ouachita Trail at Walter B. Jacobs Memorial Nature Park. I was inspecting Paw Paw (Asimina triloba) leaves for Zebra Swallowtail caterpillars.

I have read that Zebra Swallowtail caterpillars eat only leaves of Asimina species. I have read that Paw Paw Sphinx caterpillars eat only Asimina species. I have read that there is this pyralid moth with no common name (Omphalocera munroei) that eats Paw Paw leaves so voraciously that it defoliates the trees in the middle of the summer, stimulating the trees to grow new leaves, providing the last generation of zebra swallowtail caterpillars with an unusually abundant food supply, and thus is responsible for increasing the population of adult Zebra Swallowtail butterflies that fly in the fall.

I discovered a folded Paw Paw leaf, and pried it open to peek inside, curious to see if I had found a Zebra Swallowtail caterpillar, or a Paw Paw Sphinx caterpillar, or the never-seen-by-me O. munroei. I found this. It's a Spicebush Swallowtail caterpillar. As you might guess Spicebush Swallowtail caterpillars eat Spicebush (Lindera benzoin). They are also known to eat Sassafras. Some sources say they will eat Sweet bay, Swamp bay, laurels. Caterpillars in the Field and Garden say the Spicebush Swallowtail caterpillar "lives in folded leaf shelters on the host." ON THE HOST.

That's a Paw Paw leaf I'm holding. So did I just find another host for the Spicebush Swallowtail?

http://creatures.ifas.ufl.edu/bfly/zebra_swallowtail.htm

http://www.amazon.com/Caterpillars-Field-Garden-Butterfly-America/dp/0195149874

http://www.amazon.com/gp/reader/0618254005/ref=sib_dp_pt/105-3765951-6342023#reader-link

[By the way, the Zebra Swallowtail caterpillars seem to stick to the underside of the Paw Paw leaves. I have discovered that curled Paw Paw leaves most often conceal little jumping spiders.]