Teachers of landscaping and plant ID classes can still be heard saying something like “This is a great plant to use—it’s completely pest-free!” The assumption is that insects are pests, that we do not want them in our landscapes. But this is the language and thinking of yesteryear, of a culture that took to extremes the manicured landscape aesthetic that post-WWII suburbia borrowed from late 19th-century robber barons who borrowed it from English lords…it is a culture that views nature as a thing to be dominated, and it requires constant mowing and clipping and chemical applications, until our neighborhoods look the same year round and ring with the abrasive sounds of these activities to the exclusion of what might be the sound of birds singing, or even a breeze in the trees. Bugs of all sorts are not to be tolerated; we must not allow the leaves of our plants to be consumed. Yet, for eons, countless creatures that are part of the complex web of life on earth have counted on leaves for their survival.
The thing about bugs is: even if you don’t enjoy them for their own charms, or because they evolved with us and each species is unique, we need them! They pollinate our food crops; they are first responders in dispatching with dead things; they provide the protein that allows our favorite animals, songbirds, to raise their broods. Some are considered lovely and charismatic in their own right, like butterflies and dragonflies. In some countries, insects provide a key source of protein for humans. Even here, a few adventurous foodies have begun trying them out.
Of course, bugs can be pests, bugs can be damaging; but few native insects are, because they depend on a healthy ecosystem for their own survival. It tends to be the exotic bugs, with no natural enemies in their adopted environment, that cause trouble, or our own agricultural practices, such as monocropping, or planting acres and acres of a single crop.
Yet we tend to lump all the insects together as a collective ickiness, and we wipe out insect allies along with insect enemies. Here in the Midwest, we destroy the plants our native insects depend on. Roundup©-ready crops mean that crop dusters can rain down herbicide, killing any plant that isn’t genetically engineered to withstand it. Along with those plants go the insects that depend upon them for food, many of which specialize and can develop only on one species of plant or genus of plants. The 2013 migration of monarch butterflies has shrunk to a fraction of its former size and scientists have expressed concern that the fabled migration may disappear altogether; a ride through the countryside where genetically altered corn is grown can be eerily quiet…and “pest-free.” In these stretches of country, many of the native insects have nothing to eat, and the birds that depend on them don’t, either. Monarchs, though iconic and readily recognized by most Midwesterners, are not the only native insects that lose out when we lose our native plants. Another beauty, once very common in Chicago, is the polyphemus moth, pictured above. Its widely diverse diet of the leaves of many kinds of native trees and shrubs help it survive (whereas a specialist like the monarch can eat only from plants in the milkweed genus), and it can still be found in the city, although it’s a night flyer. The adult does not eat—it doesn’t even have a working mouth!
The Chicago region is blessed with a rich and diverse natural heritage. Planting natives in our yards helps preserve what remains of that heritage. Allowing insects to have their share of the native plants upon which they rely rather than running for the sprayer is an act of generosity and kindness to fellow beings that helps heal the landscape and build healthy wildlife habitat. These creatures provide protein for the birds that eat them, and the birds keep the number of insects in check.
Scientific name: Antheraea polyphemus
Caterpillar image by photochem_PA [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
Adult polyphemus moth image by Mark Meravy