Tuesday, October 6, 2009
Gardening for the insects
image courtesy Mary Vardigan
Gardeners tend to think of insects as the enemy. It's natural - we spend time planning and tending our gardens, and when we find something munching away on our plants, it's annoying. We know pollinators are good, of course, and we want to see bees and butterflies in our gardens. We probably know that beneficial insects like ladybugs and lacewings may prey on some of the insects we consider pests. Still, the urge to get rid of a particularly troublesome insect can be compelling.
I have to admit to doing some pretty stupid things myself - like hand picking off the caterpillars eating my parsley. Anyone who know anything about butterflies knows that those were nascent black swallowtails. Mea culpa! I'll never squish anything again without knowing exactly what it is.
What really changed my whole view of gardening was hearing entomologist Doug Tallamy speak. Tallamy is an entomologist at the University of Delaware, who is passionate and articulate on the critical importance of native plants in supporting the food webs we all depend on. (I've gone to hear him give essentially the same talk five times now, and I'd go again, so you know he's compelling.) The bottom line is, native insects are a major food source for birds and other animals. And it turns out, most native insects are adapted to eat only the native plants with which they've co-evolved. Many of our non-native ornamental plants are simply inedible to these insects. No food for these insects, and food webs will begin to collapse.
I needed no convincing about planting natives - I was already doing that. But seeing my plants as food for insects - in a positive way - that was a new idea!
Tallamy focuses a lot on butterflies, since most people love them and would like to have more in their yards. But to have butterflies you've got to have caterpillars, and something for them to feed on. Caterpillars are also major food source for birds and for their young. In his talks and in his book, Tallamy's photos of weird and wonderful caterpillars are fascinating.
If you can't go hear Tallamy in person, buy his book, Bringing Nature Home: How You Can Sustain Wildlife With Native Plants. The book, and his website, lists the plants (mostly trees, with oaks at the top of the list) that support the most lepidoptera species. Visit http://bringingnaturehome.net/. You'd have to have a heart of stone not to be convinced.