Books & Prose


Discoveries in the Insect World

By Anna M. Warrock

Nature can be wonderfully specific. Yes, monarchs love milkweed—there’s a toxin in the plant that makes the brightly striped caterpillars distasteful to predators, and somehow the monarchs figured this out. But it’s not just monarchs that are linked to specific plants.

The grapevine beetle (Pelidnota punctate) came back on the river grape that frames my front porch. Also called the spotted June bug, this beetle simply appeared when I first planted the vine (five years ago). I don’t know of other river grape vines except maybe a half-mile away; mine was a pass-along plant. The beetle, soft tan with dark spots on the edge of its elytra (the hard shell “wings” protecting the real wings) eats holes in the leaves but does not do much damage and is not considered a major pest. Among plentiful leaves, it happily occupies its small link in the ecosystem.

A spicebush swallowtail butterfly (Papilio troilus) has made a chrysalis next to my spicebush tree (Lindera benzoin)! I grew up in southern New England with this tree and so love its fragrant leaves that I had to have one in my backyard. It tries to grow big. I prune it ruthlessly. So far it forgives me and continues healthy. The spicebush caterpillar feeds only on spicebush and sassafras trees. Both have an acid related to the cinnamic group of acids—cinnamon and other fragrant compounds. While lifting the slate cover off the pot of dirt I use to cover my compost, I saw the caterpillar—please google to see its distinctive goofy markings —with some webbing holding it to the slate, upside down. I checked a day later, and it had already morphed into looking more like a chrysalis, a bit like a dried leaf of irregular shape. The pupae can birth itself in two weeks—or next spring. It has shown no movement to date. After some worried consultation, I’ve moved the whole shebang under the porch to protect it from predators, disruptive humans (me), and winter snows. I propped up the slates with shims so the butterfly can come out. I don’t think a winged beauty could slip through the same very narrow opening as the goofy-looking caterpillar.

I’m not so happy with a newly noticed pollinator, the bee-fly (Anthrax anthrax, so named because of its coal-black body, not because of the disease). Its striking black-and-clear-patterned wings at rest are spread out like an airplane’s, and its long proboscis makes it a good pollinator. However, this predator lays its eggs in chambers where bees lay their eggs, such as a ground-nesting bee or bee hotel. I have had ground-nesting bees in the past in my moss garden, but I will have to let nature battle it out and hope those bees get a respite.

Originally published in slightly different form in the Somerville Garden Club newsletter, 2018.