Shoot the poop | Science News for Students

Shoot the poop

Some caterpillars get rid of their waste with ballistic force.
Jun 27, 2003 — 12:00 am EST
silver spotted skipper caterpillar

This silver spotted skipper caterpillar was photographed in the Julie Metz Wetlands of Woodbridge, Va.

JUDY GALLAGHER/WIKIMEDIA COMMONS (CC BY 2.0)

Most animals have terrible table manners. Dogs bury their faces in their food. Cats drag dead rodents through the house. Cows pass gas with abandon. You might get yelled at for imitating these creatures at the dinner table.

If you really want to get yourself kicked out of a restaurant, though, try acting like a caterpillar. Tie your hands behind your back and hurl your feces across the room.

That's right. Some types of caterpillars actually shoot their waste pellets as far as 3 feet away.

Instead of giving etiquette lessons to the fuzzy crawlers, Martha Weiss of Georgetown University in Washington, D.C., sought to understand this rude behavior in one type of caterpillar, the silver-spotted skipper. She tested three theories.That's right. Some types of caterpillars actually shoot their waste pellets as far as 3 feet away.

The first theory for poop propulsion is that it lowers the risk of disease. Yet Weiss found that caterpillars in feces-filled containers were no more likely to get sick than caterpillars in clean containers.

Next, Weiss tested the idea that caterpillars spew waste in order to keep their leafy structures clean. Experiments did not support this theory, either.

Instead, caterpillars that sat near their waste deposits were much more likely to get killed by predatory wasps, Weiss found. Spewing their feces far away seems to protect the creatures from harm.

Your caterpillar impression might be less successful. No matter how hard you try to explain your own appreciation for the wonders of Nature, you’ll probably never eat at that restaurant again.

Milius, Susan. 2003. Ballistic defecation: Hiding, not hygiene. Science News 163(May 3):286.