Late summer is butterfly season. Even though some butterflies can be observed gliding about in the spring and early summer, by the middle of summer butterflies of all types are easily seen pretty much everywhere.
North Carolina is home to more than 150 types of butterflies, all of which have unique nesting, overwintering and food preferences. Each butterfly differs in the way they spend the winter – some species overwinter as adults alone or huddled together in protected areas, while others prefer to stay tucked away in their protective chrysalis and emerge as adults when the weather warms up.
As adults, butterflies are generalist eaters and feed on the nectar of shallow compound flowers that are easily accessible such as sunflowers, echinacea and liatris. Most species require very specific plants on which to raise their young, however.
Pipevine swallowtails are an excellent example, as their young rely on incorporating certain acids found in pipevines and Virginia snakeroot into their bodies as a way to ward off predators. This repurposed chemical defense has proven to be so effective that many of our other native butterflies mimic pipevine swallowtails in order to take advantage of their well-feared warning colorations.
The colorations of black swallowtails, spicebush swallowtails and red spotted purples are all designed to fool nearby predators into thinking that they too have these acids flowing throughout their bodies.
The pipevine swallowtail is one of the most abundant summer flutterers in the area, and has a distinct semi-circle of orange spots backlit by a dramatic blue hue on their wings that has also given the species the common name blue swallowtail.
Butterfly wing colorations are caused by complex configurations of individual cells that create colors through pigments and/or by altering the direction of light that passes through them. These wing colorations are used to attract mates and usually display a warning signal or help to camouflage the insect. The individual scales that make up the colors on a butterfly wing also easily detach and can allow butterflies to quickly slip away from any predators that try and grab on.
Scientists currently believe that wing coloration in butterflies is influenced by the experiences that they have during their growing caterpillar phase. The color saturation in monarch butterfly wings, for example, have been shown to have strong correlations with the diet the butterfly had as a caterpillar. The more abundant food sources as a caterpillar, the more vibrant the wings in their adult form. Information for wing coloration isn’t the only thing that caterpillars seem to carry over into their final butterfly forms.
After a caterpillar has eaten its fill, it spins a protective shell in which to undergo complete metamorphosis. This happens when the creature secretes enzymes that actually break down its body into caterpillar goo. The entire body isn’t broken down, however.
Scientists have found that portions of the brain, along with other packets of specialized cells, survive this process and use the nutrient rich goo around them to rebuild into a butterfly. Amazingly enough, this gives butterflies the ability to remember experiences from when they were a completely different creature.
The intricacies of butterfly wing coloration and metamorphosis are areas of intense research, however many of the methods these insects use in order to survive are still a mystery at this time.
Planting for butterflies is straightforward – make sure to have plenty of wide, shallow flowers for butterflies to use for food as adults. Also, plant as many native plants as possible in order to give the species in your area plenty of space to raise their young.
Brannen Basham and his wife, Jill Jacobs, operate Spriggly’s Beescaping, a business dedicated to the preservation of pollinators. Contact him at firstname.lastname@example.org.