Butterflies seem gentle as they flutter from plant to plant. But some may be more murderous than you imagine. Naturalists recently witnessed several species of milkweed butterfly harassing, subduing and subsequently feeding on milkweed caterpillars, presumably to get their fill of toxic alkaloids inside the larvae.
This behavior was described in an article published Wednesday in the journal Ecology. The authors of the paper say they are unaware of similar behavior being documented among other butterflies or any insects, for that matter, that are so closely related. Although butterflies had previously been observed feeding on grasshoppers that harbor toxic alkaloids, no one had ever documented adult butterflies stealing such compounds from their own kin.
Scientists did not have a word to describe this toxic behavior, so the study’s authors came up with one: kleptopharmacophagy.