The Species That Saved Me

Chapter 2: Darapsa myron

If you're still reading this, thank you. Now we're going to talk about something that gets me amped up by a different means. You're going to read some absolutely unhinged shit in the next few chapters, such as the time I pricked my finger to see if a moth drinks blood. We're going on an adventure that starts with an attempt at getting mantis food and ends with my first publication.

No, I'm not going to tell it in that order! Let's start by talking about what exactly Darapsa myron is. Darapsa myron, or the hog sphinx or virginia creeper sphinx, is a small moth of the family Sphingidae. The sphingids are often called hawkmoths, and most people have heard of them. At least the family of sphinxes, like the hummingbird moths or that big hawkmoth your tobacco hornworms become. I'm certain a great number of people who know of the Sphingidae do not know of D. myron. It's a relatively common sphingid, or at least it shows up more often in traps and collections than most sphingids, even the ones that are similar in size. Ok Paonias myops is a similarly-sized very abundant sphingid, but for some of the same reasons. First, these two moths are small. Smaller organisms tend to have larger population sizes than larger ones. Now, they're not smaller than the vast majority of the Lepidoptera, but they're at about the right size for us to notice them. They'd be very unnoticeable at smaller sizes, but noticeable if larger. They're very common for something that we'd stop and admire. Everyone admires a luna moth because it's not only pretty, but you more than likely will never encounter one in your lifetime. While a greater number of us know what a luna moth is, a greater number of us will ever have a run-in with D. myron.

It's also important to note that while D. myron is a dietary specialist, feeding solely on native members of the Vitaceae, its hosts are fairly ubiquitous. Have you ever seen a wild grapevine? These things have the capacity to take over large swaths of land! A single grapevine can trail up a 60+ foot tree, sending down weeping vines along the length of the main trunk. A few little anchors to the ground is all you need to coat a reasonable surface area. If you've ever been to a beach in Narragansett, Rhode Island, you'll take note quite readily of the "piles" of beach grape plants along the roads!

Being a specialist with a ubiquitous host is a great combination. One summer, I reared Callosamia promethea alongside C. angulifera under the same conditions indoors. Callosamia promethea is a generalist, with a great number of hosts in several families. Unlike A. luna, C. promethea shows relatively little geographic specialization in host usage, but they don't have as wide a range as A. luna. Callosamia promethea will eat sweetgum, tulip tree, ash, cherry, spicebush, sassafras, and a few other things. Meanwhile, C. angulifera feeds exclusively on tulip tree. Now, members of the genus Callosamia are best reared outdoors on live hosts in sleeves. However, tulip tree is really fucking hard to sleeve over because they aren't particularly common trees, and so you'll be hard-pressed to find a young tree. If you can't find a young tree, you'd need a fucking bucket truck to get 20+ feet off the ground to reach even the lower branches of a tulip tree. Now, I'm not saying nowhere are there sleevable tulip trees, but I've never been around any. Meanwhile, hosts like hickory and cherry are all over the god damn place and you'll very quickly find young saplings (some cherry species don't get all that big anyways) no matter where you're at. So I set out to rear both species indoors. I found the previous year that C. promethea are easily reared indoors on cherry provided they're in a ventilated setup by an open window (they crave airflow). While C. promethea larvae actually get bigger outdoors on spicebush or sassafras, these 2 hosts wilt pretty quickly after being cut, unlike cherry. While the C. angulifera didn't do particularly well indoors, the surviving larvae not only took about half the time to reach maturity compared to C. promethea despite being much larger. I suspect that by being a specialist, C. anguilifera is able to convert host biomass to insect biomass more efficiently, leading to a higher relative growth rate than the generalist.