Your childhood readings of The Very Hungry Caterpillar will do little to prepare you for today’s featured creature, because these particular caterpillars are not the cute, fuzzy, slow, living-bootbrush kind of creatures that you’re thinking of. These ones are quite rare specimens among caterpillars, even though their genus Eupithecia are found around the world, and they’re a terrific example of the stunning specificity of survival adaptions that occur on isolated islands. Because unlike their seed- and plant-eating cousins, these caterpillars eat meat.
These hunting Eupithecia — which have been given the excellent common name of “grappling inchworms” — have a pair of hair-like appendages on the abdomen which, when touched by prey like the common fruit fly, cause the inchworm to arch itself backwards, deploying its frankly bad-ass-looking grappling arms to grab the insect before it can escape. Then it eats it, because delicious, right? They also employ some pretty ingenious techniques — like the “looking like a stick” technique and the “just the edge of a leaf, nothing to see here” technique — to disguise themselves, so hapless prey won’t know what hit them until, well… it hits them. And even then they might not know, because they’re flies and if we’re honest, flies just don’t seem like the most well-read species to me.
Because Hawaii lacks many of the other forms of predatory insects that are found elsewhere, these inchworms apparently found a vacant ecological niche — and a very plentiful food source — and adapted to fill it. By being awesome. Less than 1% of the planet’s known 160,000-odd species of butterflies and moths eat other insects, and no other Eupithecia do outside of Hawaii.
The following absolutely gorgeous video from the absolutely fantastic BBC documentary series South Pacific is kind enough to offer you excellent video footage of this caterpillar in action, with the added bonus of narration by Benedict Cumberbatch:
(If the embedded video isn’t working for you, just click here.)
(On a side note, I can’t recommend this documentary series highly enough; it’s beautifully filmed, beautifully produced, beautifully narrated, and endlessly fascinating. You can purchase a copy from the BBC America shop, the BBC UK shop, or I would imagine from any major DVD retailer. You can also rent the discs on Netflix, though tragically as of this writing it isn’t available to stream.)