Friday, July 30, 2010
When Life is Hanging by a Thread
There are two things I’ll bet you don’t know about the lowly caterpillar:
1 – Why is it called caterpillar?
2 – Why do you often see one hanging from what looks like a spider thread?
A1 – The name caterpillar supposedly derives (as usual) from a French word, meaning “hairy cat”. The hairy part I get, but cat? Let’s send that one back to the etymological drawing board.
A2 – caterpillars have a real problem. They have really really poor senses of sight, hearing and smell.
Imagine a caterpillar sitting on a leaf.
The wind blows and rustles the leaf, no problem.
A twig falls and strikes the leaf, not at all scary.
A fly lands on the leaf, our little furry fella yawns.
But when a wasp lands on the leaf and starts to approach his blind and deaf prey, the little guy shoots out a silk thread which sticks to the leaf, and leaps over the edge, dangling out of sight and out of danger. After the bloodthirsty wasp departs, little caterpillar hoists himself up the lifeline and resumes his busy eating schedule.
Prof. Ignacio Castellanos (Hidalgo, Mexico) has proven that the caterpillar can distinguish between all of these various motions of the leaf by mere sense of touch.
How did it learn to do that?
(Sometimes I wonder why biology departments are not full of religious people.)
Here’s a summer challenge for you….When you are outside, enjoying the warm weather and natural beauty of this world, find the “picture perfect” moment (butterfly, sunset, etc.) and DON’T take a picture. Take it in with a deep breath, knowing that it is THIS moment that counts, not the digital memory of it.
PS – hat-tip to Highlights for Children for alerting me to Dr. Castellanos’s research!
PPS – Remember The Very Hungry Caterpillar? Creator Eric Carle has a whole zoo’s worth of sequels...click here.
Sometimes hanging by the thread brings it’s own danger:
“One ought never to turn one’s back on a threatened danger and try to run away from it. If you do that, you will double the danger. But if you meet it promptly and without flinching, you will reduce the danger by half. Never run away from anything. Never!” - Churchill