March 3rd, 2006
intervention?
If you spend any amount of time observing or photographing insects and spiders, you’ll know what I mean when I say that things aren’t exactly pretty out there. Sure, there are gorgeous butterflies fluttering among the flowers, and sweet little lady beetles racing up and down plant stems like miniature bumper cars – but the hard truth is that it’s a bug eat bug world. Vegetarianism hasn’t exactly taken the insect world by storm. Survival usually depends on eating someone else before they eat you. And it’s not just the larger fellas like the mantids and the spiders that you have to watch out for. No sir. You might be eaten by a parent or a sibling. You might even be eaten by the offspring of something that laid eggs on you when you weren’t looking. To my mind, life as an insect is risky and, quite frequently, rather gross.
Warning: Before we proceed further, if you’re the sensitive type, you might be better off *not* clicking on some of the following links, or on the thumbnails linked to larger shots. You may well not like what you see.
Now, take for instance the beautiful Hyalophora cecropia caterpillar hanging out at the top of this page. Looks like a pretty carefree life, doesn’t it? Well, the sad news is that this caterpillar was already doomed before I shot this photo. Closer inspection revealed that it had already been victimized by one of several species of insects that lay their eggs on these large caterpillars. Just a few hours after I shot this photo, some species of parasitoids were already hard at work burrowing into its body. Unfortunately, there wasn’t much that could be done for this caterpillar. Just shoot some photos and leave it contently munching on Buckthorn leaves.
Other times, like some downbeat oracle, it’s easy to anticipate trouble ahead long before it happens. That’s when the question of “intervention” arises. Do you try to change what is likely to be, or do you just let nature take its course? I found myself faced with such a dilemma in late August after discovering a very tiny Monarch (Danaus plexippus) caterpillar feeding on the upper leaves of a Common milkweed plant in the garden. It seemed safe for the moment, although I was a little concerned about a spider lurking inside a funnel web on a nearby leaf. However, the spider seemed to be ignoring the caterpillar, so I left them to their own devices with the intention of watching to see how they got on. A couple of days later, while making my insect rounds in the garden, I found that the spider had killed a predatory stinkbug that must have climbed to the top of the milkweed plant. Fortunately, the caterpillar remained unharmed and, in fact, had grown considerably since my last visit. I briefly considered removing the caterpillar to raise in a jar indoors, but decided that I’d leave it in the protection of the spider.
Now, my reason for leaving the Monarch in the garden was not because I wasn’t up to the challenge of rearing a caterpillar. In fact, I’ve been fairly successful at bringing the odd caterpillar indoors to raise when I wanted to photograph a transformation from larva to moth or butterfly. These are a couple of examples of caterpillars which cocooned in a jar in my kitchen in Summer 2004. The first set of photos are of a Rusty Tussock Moth (Orgyia antiqua) and the second set are of a Virginia Tiger Moth (Spilosoma virginica). As you can see, the moths did not appear to suffer from my intervention.
So, why didn’t I bring the Monarch caterpillar indoors? Why did I leave it out in the garden where life or death was entirely up to fate? In truth, I’m not exactly sure. I suppose I felt that the Monarch was probably better off outdoors, picking and choosing what it wanted to eat. After all, rearing insects indoors is not entirely without risk. Sometimes caterpillars die for unknown reasons, so perhaps they’re better off taking their chances out in the garden.
As it turned out, leaving the Monarch in the garden was a bad mistake. The next afternoon, when I checked on the caterpillar and the spider, I found a depressing sight. The fickle-minded spider must have decided to wander off in search of better hunting grounds. In its absence, a predatory stinkbug had seized the opportunity to move in for the kill. I found the Monarch caterpillar, suspended in the remnants of the spider’s web, the stinkbug draining the last dregs of fluid from its lifeless body. Although I’m quite accustomed to gruesome scenes of life and death in the insect kingdom, I felt troubled by the sight of the dead caterpillar. Should I have intervened a day or two before and brought it indoors? Knowing just how high the chances are of a Cecropia being parasitized by one of several species of flies and wasps, should I also attempt to salvage any uninfected caterpillars I come across and raise them indoors?
How far do we carry intervention? Is it right to meddle with nature? Do we deprive one insect of its life, or another of its lunch? It’s a tough call.
Tags: hyalophora cecropia, spilosoma virginica, orgyia antiqua, danaus plexippus