Killer caterpillars?

Caterpillars may have poisoned Kentucky foals

source: New Scientist July 21 2001 p17

Some 500 racehorse foals have died from unknown causes in Kentucky in early 2001, and researchers from Kentucky University are investigating a theory that the foals could have been poisoned by caterpillars. Many affected foals showed similar symptoms to those of cyanide poisoning. Many of these foals had also grazed near cherry trees, and cherry leaves contain a cyanide-related compound called prunasin. Caterpillars may have eaten the leaves, then travelled to the pasture, following a frost. The foals may then have consumed the caterpillars, or their faeces.