Bugs & Moonshine

Regal moth caterpillars in sleeves in my front yard. In the close-up you can see them -- they are about an inch long now. I used nylon screen for my sheeting material because it's hot here in Charlotte and I didn't want them to cook, but normally any thin fabric will do.

When I was a teenager, I made a fair amount of money for a couple of summers farming some unusual produce. No, it wasn’t illegal, though it was ethically sketchy (more on that later).  Actually, drug dealing would have been more socially acceptable among my peer group at the time.

Who wants to go back to school and answer the question “what did you do all summer, man?” with “I raised caterpillars in my backyard. Thousands of caterpillars…” and then, as the line goes in “Alice’s Restaurant,” “they all moved away from me on the bench.”

I grew up in a fairly small, fairly idyllic college town in upstate New York, where a lot of college students decided to stay every summer, to fill up the local swimming holes and take all the temporary summer jobs. This meant that local kids were pretty much out of luck for summer employment, unless you had a parent who owned a small business that boomed in the summer. I didn’t, which meant I was generally without pocket money  and had to spend a significant number of hours painting our house, chopping fireplace wood, mowing lawns, etc., etc., FOR FREE, because may father wanted to be sure I “was occupied.” As we said then, it was a “major bummer.”

I didn’t have a real job but, as I have said in a previous post, I did have a significant hobby – insect collecting. As a huge bug-geek, I got some insect collector newsletters, and one of them had classifieds, where people sold collecting equipment and … specimens. Reading these ads carefully, I noticed that some of these advertisers sold live bugs – notably giant silk moth cocoons. Collectors liked hatching moths to get “perfect condition” moths for their collections.  This gave me an idea.

I had grown caterpillars from eggs before and I knew the basic mechanics – catch female moths,  force them to lay eggs in paper bags, then find a source for the food plants. In the past, I’d grown caterpillars in dry aquariums. It was a lot of work, because you had to go out every day or so and cut fresh branches and clean the terrariums regularly or you got mold, which was yucky and killed the caterpillars. I knew there was a better way (there are instructions in some of the field guides) to do this outdoors with live plants, called “sleeving.”

Sleeving is a method by which you can farm caterpillars on a large scale. It’s a basic technology that, I suspect, was invented to grow silk moth caterpillars for the silk trade. “Technology,” in this case means a fabric tube that you can slide over a branch and tie tight at both ends, enclosing the caterpillars and the leaves. The idea is to keep the caterpillars from escaping and to protect them from predators – especially birds and parasitic wasps, which kill them in droves in the wild. If you make the sleeve big enough, you may never have to handle the caterpillars at all until they pupate. A bed sheet, sewed together at the long edges, is ideal, because the tube is big enough to enclose a large branch which can feed maybe a hundred caterpillars through their larval lives. Bed sheets are thin enough to allow the tube to “breathe,” so moisture doesn’t collect inside the tube and the caterpillars stay dry and healthy.

June was the prime collecting season for most of the large, showy, “collectable” moths in my region, and I had some great places to hunt them, a couple of miles away in the countryside, where mercury lights on some industrial and commercial buildings happened to be near some big open spaces and natural flyways. I and a couple of friends would ride out every night it wasn’t raining and collect. The year I started “farming,” we caught multiple gravid (fertilized) of all the locally common species of giant silk moth – luna, polyphemus, cecropia, io and even one promethia moth (not a common insect in upstate NY). We also caught egg-laying females of about 10 species of sphinx moths – otherwise known as hawkmoths – large bodied, often beautifully colored moths with long, powerful narrow wings. I had the raw materials to stock about a dozen large sleeves, though I knew that I might need even more when the caterpillars got bigger. It’s a little hard to guess how much forage a hundred  (or so) large caterpillars will eat.

I paid about $10 to put an ad in the newsletter, listing the pupas/cocoons I would have available later in the summer and their prices (I guessed at what I could ask, charging more for rarer species, and factored in the cost of mailing and supplies). I really had no idea if anyone would buy any, but I assumed somebody would buy something. I assumed my customers were kids like me, and a couple of years earlier, I would have bought some.

My mother, fortunately, had a lot of old, worn bedsheets which she didn’t mind getting rid of (I had to buy a few cheap sheets at Woolworth’s)and one of my friends’ mothers had a sewing machine and was willing to sew the tubes (our parents were largely academics, and they were willing to encourage strange hobbies). I had many of the food plants in my backyard, and another friend had a small patch of woods out behind his house which had the rest. I simply tied  the sleeves on the trees, cut the eggs out of the paper bags, put them in, tied the sleeves closed and waited.

Meanwhile, the mail started coming. I got nearly a hundred orders. Some of my customers ordered a lot of pupas. Some were business addresses in NYC, which, I  realized later, were dealers selling specimens to collectors around the world. My sphinx moth pupas were particularly popular because few of the semi-professional “growers” (there were not many back then, but there were a couple) bothered trying to growing them. My father, seeing the money roll in, largely let me escape from painting the house.

There was a folk song that I liked to sing back then:

Get you a copper kettle, get you a copper coil
    Fill it with new made corn mash and never more you'll toil
   You'll just lay there by the juniper while the moon is bright
Watch them jugs a-filling in the pale moonlight.

It was like that: vaguely weird, vaguely criminal (was shipping insects around the country through the mail legal? my dad wanted to know), and somehow beautifully lazy. It was fun riding around in the midsummer night  on my bike like a bandits, collecting moths, building my stock. It was easy work tending the caterpillars – I just made the rounds every few days, checking the sleeves, letting the droppings fall out, making sure there were plenty of leaves still left. It took me no more than 4 hours a week, at least when the caterpillars were small. It left a lot of time for lying in the hammock with a book and going swimming with my buddies in the gorges.

But there were some anxieties, as there is with any entrepreneurial venture. After I first put the eggs in the sleeves, I didn’t check them for two weeks, knowing they would take a while to hatch. We had a lot of rain and I worried that they might be drowned by it. When I opened the first bag, I saw nothing, absolutely nothing at first, and I immediately thought “Oh, no – I’m going to have to send all that money back!” Then I noticed a fine powder of minute droppings at the bottom of the bag… I started gently flipping through the leaves – there were tiny black cecropia caterpillars everywhere.

All-in-all, most of the caterpillars I was raising were very easy to grow, and sometimes they grew surprisingly quickly.   I would open a bag where nothing had been visible beforeand there would be a whole herd of large, odd-looking caterpillars grouped together on the twigs, like an alien invasion. Some of them thrashed or clicked their mandibles (they don’t really bite) when I alarmed them. I discovered that many of the sphinx caterpillars actually had multiple color forms within the same brood. Some of them were startlingly lovely, at least to my bug-loving eyes. Here are photos showing a few of the species I raised:

And, of course, there were farming “issues.” Raising these large caterpillars in a high density environment is not natural, and sometimes a sleeve would catch a disease, which would wipe out most of the caterpillars in it.  (All farming is unnatural in this way, and human farmers have had to deal with diseases and pests since the beginning.) One sleeve got raided by a raccoon, which tore open the tube and ate all the caterpillars.  (This is the caterpillar farming equivalent of the “cow in the corn.”) Fortunately, most of the losses were among the giant silk moths, where I had lower demand and duplicate broods.

And there was no agriculture textbook or cooperative extension officer for me to go for answers to some of the rearing questions I had. I had to figure a lot of things out by guesswork. Cecropias make their cocoons in the branches where they feed (easy) but lunas (harder) usually make their cocoons on the ground in the dead leaves. I put the luna caterpillars, once they stopped feeding, in a big cardboard box with a bunch of freshly picked loose leaves. An even bigger problem were the sphinx caterpillars (hardest) – they normally go to the ground, dig a burrow and pupate inside it. How do I duplicate an environment for that? I tried putting loose dirt in a box, but they didn’t like it and wouldn’t dig (I guess the dirt was too loose). I finally solved the problem by putting a six-inch layer of damp sphagnum moss, mixed with a little bit of regular dirt, in the boxes – this made a soft soil they could tunnel through. (The moss made good packing material for shipping later.) I learned some things about insect biology in raising these insects. How do you efficiently mail pupas? Art mailing tubes worked, and could be cut to custom lengths to match the order.

A sphinx caterpillar that is about to pupate. It's easy to tell: fifth instar caterpillars suddenly change color slightly (note the brown back), stop eating and start wandering. 

One big thing I learned was that I needed to pay attention to the insects if I wanted to understand them.  As they got big, I got nervous about how I would know to remove caterpillars when it was time for them to cocoon/pupate – if  I pulled them out too soon, would they starve?  As it turned out, it was a no-brainer. Caterpillars about to pupate change color slightly and begin to wildly wander. Every day, I would find a few at the bottom of the bag, wandering around: they were ready to go into a box.

In the end, I was able to make almost all my orders (I still had a lot of cocoons from some species left, which I let go when they hatched the next spring – I more than replentished my wild source), and, after paying for all my supplies and mailing, I made around $500, which was real money back in the late 60s. It was more than anyone else I knew made that summer – at least legally. I didn’t brag to other kids though --most people just wouldn’t understand.

I farmed caterpillars the following summer as well, and was almost as successful. I had repeat customers, which meant that the pupas I shipped had survived mailing. When I was in college years later, I was still getting inquiry letters asking if I had “stock” to sell.

Thinking back on it, caterpillar farming was both the best and oddest “job “ I ever had.  I didn’t know it, but I was an entrepreneur, and a biotech entrepreneur to boot. It was a job that required imagination, vision, a little bit of craziness, and just plain luck. It was fun, a-watchin them sleeves a-fillin, in the pale moonlight.