Research Highlights

Nature 458, 389 (26 March 2009) | doi:10.1038/458389c; Published online 25 March 2009

Entomology: Sick bugs take drugs

Entomology: Sick bugs take drugs

E. CARLE/PUFFIN

PLoS One 4, e4796 (2009)

The Very Hungry Caterpillar (pictured) in Eric Carle's children's book, which saw its fortieth anniversary this year, may have been hunting for drugs as well as food.

Woolly bear caterpillars (Grammia incorrupta) normally ingest small amounts of pyrrolizidine alkaloids to ward off parasites. Michael Singer of Wesleyan University in Middletown, Connecticut, and his team showed that the caterpillars ingested around twice as much of the drug when infected by maggots.

This finding suggests that self-medication is more widespread than previously thought — it has never been clearly demonstrated in insects before. Previous studies by the team have shown that the taste receptors of infected woolly bears are altered to crave more alkaloids when they are infected.