Carnivorous Caterpillars? Only in Hawaii!

Hawai’i has meat-eating caterpillars.  Did I get your attention?  The only place in the world where evolution took this bizarre turn for the normally cute caterpillar, moth caterpillars in the genus Eupithecia catch and eat other insects.  First discovered in 1972, these tiny ambush predators lie in wait on leaves and snatch flies out of mid-air.  The different species have different colorations to fit the plants they prefer to sit on; some are brown and look like twig, some are green and look like a stem, while one looks so much like a fern leaflet that it cuts out a notch in a fern sets up shop like it was any other leaf on the frond. These caterpillars aren’t easy to find. They are mostly found in native forest areas which are rare and often accessible only with permission from the land owner or with a guide. Then comes looking under every leaf and on every twig to just see the buggah! We went out several times to check out new hikes with the secondary goal of finding one these caterpillars along the way. You know that saying about not seeing the tree for the forest? You can end up using up a lot of daylight looking at just one bush along a trail (see, it’s not all just mai tais and beaches for us!). Then there’s the problem of getting an in-focus shot of a tiny subject, hence the included picture. You can forget about catching one in the act of eating a fly, too. Fortunately, the internet allows us to see such things from the comfort of anywhere these days. Robbie Gonzalez put together a few good clips from a BBC special that you can see here. It is theorized that such a radical behavior change came about to survive the remote, alien world that is the Hawaiian Islands.  Many insects have co-evolved with certain plants over such a long time that the plant becomes the sole food source, at least in some stage of the bug’s life.  Think monarch butterflies and how their caterpillars only eat milkweed plants.  To simplify a long and complicated process, in lieu of their preferred food, the caterpillars of Eupithecia adapted to eating something that was available- other bugs.  Hawaiian flora and fauna has many examples of strange and amazing adaptations, but none quite as unique as the meat eating caterpillar!

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