- Nature News By Marlene A. Condon
- AUG 1, 2023

Gardening is in full swing at this time of year. Sadly, many a gardener will kill practically any kind of insect found on his plants, even if he doesn’t know what the insect is and whether it will even seriously harm the plant he found it on.
One type of insect that has a particularly bad reputation is the caterpillar. Caterpillars are the immature or larval form of moths and butterflies, and, except for the Harvester butterfly whose carnivorous caterpillar eats aphids, they feed on plant material. This week, I want to try to convince you not to destroy caterpillars because moths and butterflies are disappearing from our midst.
In a nature-friendly garden, caterpillars do not create havoc. Defoliation of native trees and other native plants by native caterpillars is rarely a problem due to native-predator populations that evolved along with these insects. Predators help to limit overpopulation of their prey, which limits how much plant material gets eaten. That’s why any area, whether it be a homeowner’s yard or a farmer’s working acreage, is more prone to insect damage if the land is not maintained in an ecologically “smart” manner.
Unfortunately, natural predators are often wiped out due to habitat loss, which is what has happened with Loggerhead Shrikes that had lived around farms in Virginia. These birds (that somewhat resemble Northern Mockingbirds) ate mostly insects. But, they needed hedgerows for nesting and for storing food. Because modern farms have become almost as manicured as most homeowners’ yards (not an ecologically good thing in either case), a hedgerow between fields has become a thing of the past.
Predators also succumb to the deliberate killing of insect “pests” — a term I consider inaccurate — via the use of insecticides. Many predatory insects, such as our native Carolina Mantids, will die right along with the intended “victims.” Because there are naturally a smaller number of predators than prey, it should go without saying that killing those few predators helps to make a garden or farm more prone to overpopulation of the prey insects that then can’t help but cause plant damage. They need to eat!
However, no animal is supposed to eat itself out of house and home. People think caterpillars exist to cause the deaths of their food plants, but that doesn’t make sense. How could their species continue to survive? Dead plants can’t reproduce to create food for current or future caterpillars, which means that at some point, these organisms would not be able to obtain nourishment and would die.
The overpopulation of any species dooms the environment to dysfunctionality. It can’t function properly when it’s out of balance.
A more selfish reason to leave caterpillars alone is so you’ll have the opportunity to view the beautiful creatures that comprise the adult forms of some of them. Many moths and butterflies are as joyful to behold as the painted canvases we must travel to an art gallery to see. But garden properly and these airborne canvases will come to you!
Marlene A. Condon is the author/photographer of The Nature-friendly Garden: Creating a Backyard Haven for Plants, Wildlife, and People (Stackpole Books; information at www.marlenecondon.com). You can read her blog at https://InDefenseofNature.blogspot.com
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