Science Diary: Caterpillars – Alien
Ambience: rainforest
LD: “Spooky movies always draw from nature. The insect world provides some of the most gruesome interactions that you, that you could imagine. And parasitoids are like that.”
JM: Remember in the movie Alien, when a creature makes a dramatic exit out of its human host, giving a new meaning to the term stomachache? The real-world creatures that the alien monster was based on are called parasitoids. Welcome to Pulse of the Planet’s Science Diaries, a glimpse of the world of science from the inside. Lee Dyer is an ecological entomologist who studies parasitoids which prey on caterpillars.
LD: “Let’s say that it’s a parasitic wasp. The female has mated with the male, so she’s got some eggs to lay. And wasps have these things called ovipositors and it’s like a straw and they roll their eggs down the straw. So they take that ovipositor and they stick it inside of a caterpillar or any other insect, and they actually release some venom usually. And sometimes they even release viruses that stun the caterpillar for a while, sort of shut it down, and they roll their eggs down inside of there. The larva hatches out of that egg. The larva is like, it’s an immature wasp. It’s sort of the caterpillar form of the wasp; it’s that stage. And the larva consumes important tissue inside the caterpillar, and they grow along with the caterpillar. As the caterpillar is eating, the wasp larva is eating. But then when they get old enough, they need to pupate. Then they eat everything. They eat the brain; they eat the heart; they eat all of the insides of the caterpillar. Sometimes literally thousands of them will come popping out of a caterpillar.”
JM: We’ll hear more on Lee Dyer’s work with caterpillars in future programs. Our latest project is a competition for third to sixth graders. Check out kidsciencechallenge.com. Pulse of the Planet’s Science Diaries are made possible by the National Science Foundation. I’m Jim Metzner.