In the Americas, there is but a single species of carnivorous butterfly. Unlike other American butterflies whose larvae feed on plants, caterpillars of the Harvester (Feniseca tarquinius) feed only on wooly aphids! Living wooly aphids! Throughout the range of the Harvester in eastern North America, various species of wooly aphids are utilized for food. Here in peninsular Florida, just one species of wooly aphid is used, Neoprociphilus aceris, an aphid that feeds uniquely on spiny greenbrier (Smilax) vines.
The caterpillars are small, slug-like creatures that frequently feed in groups. Locally, It is common to see several caterpillars together, working their way along a greenbrier vine, chomping down all the aphids as they go.
Amazingly, the aphids make no attempt to flee from the approaching caterpillars, instead, they just wait to be the next one to be eaten! Here is what it looks like as a Harvester caterpillar tears into an unsuspecting aphid:
In many parts of the range of the Harvester, the caterpillars are myrmecophilous (that is, actively tended by ants), but I’ve never noticed ants tending Harvester larvae in Florida. What’s cooler? Harvester caterpillars produce acoustical signals, the purpose of which remains largely unknown.
So, all of this is pretty amazing! But it gets better. The pupae have been described in the literature, for over a century, as as resembling a monkey’s face. I’m not sure I necessarily see a monkey’s face in the pupa, but I definitely see a face!
Harvester adults are delicate-looking butterflies that remain close to aphid populations. They are most active in the afternoon, and males guard perches in the canopy where they await passing females. These perches are usually 2-4 meters above ground-level, but occasionally, lower perches will be utilized. Today I got lucky, and found this male Harvester guarding a perch at eye-level, allowing me to get some photos:
While there are many related carnivorous butterfly species in Africa and Asia, the Harvester is truly unique among American butterflies!