Most people really enjoy butterflies flitting through the garden. And what would a summer evening be without an occasional moth?
Generally speaking, these beneficial insects improve pollination and they are a sign of a healthy environment. Moths and butterflies (and their caterpillars) are prey animals to many predators, such as bats, birds, and lizards. The presence of butterflies and moths indicates a healthy level of biodiversity that translates into a healthier garden. The plight of the Monarch butterfly is a well known indicator of environmental problems.
Differences between butterflies and moths
The jury is still out on the exact difference between butterflies and moths. Skippers and butterfly moths muddy the taxonomic waters, but there are some clear differences (with several exceptions):
Lifecycle of butterflies and moths
In spite of the differences, butterflies and moths share the same basic 4-stage life cycle. Moths and butterflies start out as eggs, which hatch into caterpillars. These caterpillars are what cause most of the damage to garden plants. Caterpillars are voracious eaters! After they fatten up on garden plants, moth caterpillars spin a cocoon around themselves, while butterfly caterpillars form a chrysalis. Inside these tidy little protective packages, caterpillars are transformed into insects of the sky. [I just learned, watching BBC, that the Arctic Wooly Bear caterpillar may take 14 years to complete its metamorphosis and that it can survive being frozen solid!]
Moth and butterfly identification
A student at the University of Washington created a lovely animation of 42 North American butterflies. You can see it here. This is an excellent resource because it also shows range maps! Another great interactive tool can be found at Butterflies and Moths of North America.
Damage caused by butterflies and moths
While moths and butterflies won’t damage your plants, their caterpillars certainly will. This is especially true for the imported cabbageworm. During summer months, monitor plants for feeding holes, frass, and rolled or webbed leaves. Since moth and butterfly caterpillars are food to so many other critters, handpicking is the best treatment. Adding pesticides simply disrupts the natural controls already in place.
You can grow a surprising amount of food in your own yard. Ask me how!