I could have selected the harvester because it’s gorgeous or its upper side is rarely seen. I feel both are certainly true!
Rather, I’m selecting the harvester (Reniseca tarquinius) because its caterpillars are not leaf-munchers. Instead, they are carnivorous insect-eaters! Yes, of the hundreds of butterfly species in North America, the harvester is unique in this regard.
Caterpillars chomp aphids
Harvester caterpillars feed on several species of wooly aphids. The aphids, in turn, suck juices from the stems of alders and ashes. Ants guard the aphids. However, the harvester exudes a chemical that fakes the ants into accepting the harvesters as just another aphid, not a predator of them.
Harvester larva have relatively long hairs, which usually become covered with waxy secretions from the aphids being fed upon. (If that sounds a bit gross compared to the more clean-cut leaf-munchers, that’s probably because it is!)
According to Paul A. Opler, a noted butterfly authority, “The harvester’s proboscis is proportionately shorter than that of any other butterfly. Adults feed primarily on aphid honeydew,” but also animal scat.
Over the years, I’ve seen them puddling on damp gravel roads. This was the case on our July 5 Deep Portage butterfly county when my wife, Marlene, and I each saw an adult doing so.
Another behavior is when harvester males perch at eye level on edges of leaves. From there, they make mad, tumbling dashes challenging other males, then returning to perch until the next sortie.
For a human, these tumbling flights are visually challenging. For one thing, harvesters are only 1 to 1-¼ inches in size. Second, these flights are not in slow-motion, but accelerated blurs.
Over the years, I’ve learned to recognize this unique behavior belongs to harvesters. I always enjoy seeing it, even though it remains visually challenging.
Upper sides, which are surprisingly colorful, are not often seen. Therefore, I’m please I can share the photo I got on July 8 of a fresh harvester’s dorsal upper wings.
The harvester’s nearest relatives are geographically remote from us in southeast Asia and Africa. So I’m glad that this colorful, though bizarre butterfly species has found a home in our neck of the woods.
John Weber is a local butterfly and dragonfly enthusiast. Since 1997, Weber has been meticulously recording every dragonfly sighting. He’s counted butterflies since 1993. “Leps” is short for the insect order of lepidoptera, meaning butterflies and moths. “Odes” is short for odonata, or dragonflies and damselflies.