The Jewel Caterpillar
This bizzarely gelatinous, semi-translucent little creature is sometimes referred to as the “jewel caterpillar”, but it’s actually the larvae of a fuzzy orange moth called Acraga coa. This moth is native to Central and South America and belongs to a family known as Dalceridae. There are at least 84 different species of moths in this family, and all of their larvae are so gooey that they’re often nicknamed “slug caterpillars.” At the moment it’s unclear as to why they’re so strangely and conspicuously coloured—biologist Daniel Janzen at the University of Pennsylvania has raised Dalceridae in captivity and reports that the bright, conscpicuous larvae actually spend a lot of their time hanging out on the tops of leaves in full view, like they don’t fear birds at all. Some caterpillars use colour to indicate their toxicity and therefore warn predators away, but there’s no evidence that the Dalceridae caterpillars are poisonous at all. But they do appear to have one defense mechanism: their gooey, gumdrop-like spines break off easily, just like some lizard’s tails break off upon a predator’s touch. So, perhaps this allows the caterpillars a chance to get away from predators. In an attempt to study this function, insect biosystematist Marc Epstein placed Dalcerides ingenita larvae in the same environment as several ants, which would usually devour caterpillars, but these ants backed right away. The ones that tried to attack became stuck in the larvae’s jelly-like body, so the caterpillars seem to repel predators simply by being sticky and uncomfortable. “Jewel caterpillar” is a pretty fitting nickname, then—look all you want, but don’t touch.
(Image Credit: 1, 2)