Who doesn’t love butterflies? It’s always a lift to see a butterfly or neat-looking moth flutter by on warm sunny days.
At this time of year, butterflies are but a memory. Where do they go and how do they survive our winters?
Most people are probably aware of the monarch butterfly (Danaus plexippus) and their incredible migration to the warmth of Mexico each year. There has been much discussion of their falling populations due to overwintering habitat destruction and their singular need for milkweed (Asclepias sp.) for egg laying and caterpillar food in our area during the growing season. With good habitat and plenty of milkweed, they can grow into the beautiful adults which make that long trek of 3,000 (!) miles to more sunshine. (Sounds pretty good right now, doesn’t it?)
Not all butterflies migrate outside of the U.S. to survive. In fact, most of our common visitors do not.
Let’s take a look and find out how some of our other “flying flowers” manage to reappear each season.
To do this, it’s important to know about the life cycle of the butterfly. They go through four distinct phases: egg, larva, pupa and adult, for a complete metamorphosis.
Eggs are laid on a host plant, which is the food that the larvae (caterpillars) need. Different species of butterflies have different host plants. Caterpillars are eating (and pooping) machines, which grow so fast that they periodically shed their outer skin. The period between molts is called an instar. There are usually several instars before the caterpillar is full-grown and ready to enter the resting pupal stage, or chrysalis, where their incredible transformation to the adult stage takes place.
Like the monarchs, some butterflies overwinter as adults, but they don’t go as far — stopping in the warmer Carolinas or Florida. Variegated fritillary butterflies are examples of this. No passport needed!
The lovely swallowtails overwinter in their chrysalis, which is attached to bark, twigs, or other nearby structures. With its head up, a swallowtail caterpillar leans back supported by a girdle of silk and pupates, forming the protective chrysalis in which it will remain until spring. Keeping parsley, fennel, rue, or Queen Ann’s lace in your yard welcomes these beauties.
Allowing wild cherry, poplars, and aspen to grow will encourage the lovely red-spotted purple, which overwinters as a caterpillar tucked into a refuge of rolled leaves and silk. Three species of hairstreak butterflies overwinter as eggs on various oaks, wild cherry, blueberry, and hawthorn.
As always, what you plant and how you manage your landscape will conserve and encourage the magical presence of butterflies when warmer days return.
By Christine McComas, CPH, Horticulture Consultant, University of Maryland Extension, Home & Garden Information Center