Epic caterpillaring results in many cool finds

 

Cherry Dagger moth caterpillar (Acronicta hasta)

Shauna and I spent last weekend at the fabulous Highlands Nature Sanctuary in Highland County, Ohio, which is owned by the Arc of Appalachia. A bunch of us were there for our 12th annual "caterpillar safari", which is just a bunch of larvally-minded friends of ecology gathering to seek out the always fascinating caterpillars of moths (mostly) and butterflies (far fewer in numbers and diversity). Now is peak season for caterpillar abundance and diversity, and we prowled into the wee hours on Friday and Saturday nights, exploring interesting habitats. Most caterpillars are active nocturnally, so hunters of them must adjust their search hours accordingly.

Dozens of species of caterpillars were found and photographed, including this Cherry Dagger (Acronicta hasta). We brought lots of livestock back to the Arc's forest museum - our base camp - and from 10 am - 2 pm the public is invited in. Dozens of people got to see crazy larvae that they likely never knew existed. One should not underestimate the value of moth larvae (which the overwhelming number of caterpillars are). They are the primary organisms that convert plant matter into a digestible form of protein for birds and myriad other animals and underpin food webs.

Gray Hairstreak caterpillar (Strymon melinus)

We certainly do not ignore the occasional butterfly caterpillar that turns up, and this was a particularly interesting one. It is the caterpillar of the Gray Hairstreak (Strymon melinus), which specializes on feeding upon species in the Pea Family (Fabaceae). These cats resemble Mike & Ike candies and are tiny and easily overlooked.

This one is feeding on a tick-trefoil in the genus Desmodium. Many hikers know this group of plants by their triangular loments (fruit) that are thickly beset with stout hooked hairs. They evolved for mammalian dispersal, and that includes the clothing worn by humans. Those loments can be tough to get off and will even survive trips through the washing machine.

Here's what that Gray Hairstreak caterpillar in the previous image will (hopefully) morph into - one of our showiest butterflies. I say "hopefully" because the survivorship of caterpillars is astonishingly low. Just about everything wants to eat them and for some species of moths, at least, probably only one percent or so of caterpillars make it through the complete life cycle and to the mature reproductive stage. The rest become part of a great food chain. To compensate for such high mortality, butterflies and moths lay enormous numbers of eggs; a carpet-bombing strategy if you will.

Finally, a cool little-known thing about Gray Hairstreak butterflies. John Howard showed this to me a while back. Hairstreaks habitually rub their hind wings together, and the "tails" resemble antennae. Perhaps this pseudo face with its twitching antennae fools birds and other would-be predators who then lunge at the wrong end of the butterfly. While the hairstreak may lose parts of its hind wings, it might still escape to live another day and find a mate and reproduce.

Anyway, as John pointed out, if you can get directly behind the hairstreak and under it (that can take some effort), the lateral fringes form the illusion of orange eyes capped with long antennae, and even a frowning mouth below. Whether all of that evolved to spook visual predators I do not know, but whatever the case it certainly looks cool. And once a butterfly photographer knows this, they may find themselves spending much time attempting to get into position to get this shot.