On our morning walk, a tiny blue butterfly flits past and lands on a ceanothus branch. Before I can snap a picture, it flutters away. Back at home, I show husband John images from the UC Davis butterfly site. Is this the one we saw— an Echo blue (Celastrina ladon echo)? Or this one? A Silvery blue (Glaucopsyche lygdamus). He shakes his head. Here lies the problem of butterfly identification. Unless you are willing to capture and kill (I'm not) it's sometimes impossible to get a positive ID.
Butterflies and moths undergo complete metamorphosis with four distinct life cycle stages: egg, larva, pupa, and adult. To complete their life cycle, two host plants are needed: one for the larvae and usually a different one for adults. If you know the adult butterfly's plant host you have an added clue to identification. For example, hosts of the Echo Blue are ceanothus and California Buckeye while the Silvery Blues favor lupine.
Not surprisingly, ceanothus attracts many of our local butterflies. Some of the simplest to spot are the Pale Swallowtail (Papilio eurymedon), the Mournful Duskywing (Erynnis tristis), and the California Sister (Adelpha californica). Pale Swallowtails are creamy-white with black stripes and distinctive tails on the bottom of each hindwing. The Mournful Duskywing is easy to distinguish by its dark brown-black upper wings. The California Sister gets its name, sister, from the white bands against a dark background resembling a nun's habit. An orange patch marks the tip of each forewing. Caterpillar hosts for all three include the various oaks: coast live oak, blue oak, and valley oak.
The order Lepidoptera (from the Greek scale wings) encompasses moths as well as butterflies. Although there are exceptions, butterflies tend to fly in the daytime while moths fly at night. One of our most colorful moths can be seen at dusk flitting around the blooming desert willows that line the parking lot of the Paso Robles library. The Sphinx Moth (Hyles lineata, photo above) is sometimes confused with a hummingbird due to its large size and flying patterns. As caterpillars, they can be quite voracious, capable of damaging crops. One solution is to eat them before they eat your tomatoes. According to M. Tarre's Fit to Be Eaten: A Brief Introduction to Entomophagy, "The nutritional value of the larvae...contain almost as much fat as hamburger meat, but have almost one-third less saturated fat, and more energy (in calories), protein, carbohydrate, riboflavin, and niacin than hamburger meat."
Whether you're an identification geek like me or just out to enjoy the beauty of our fluttering friends, enjoy them while they last; most butterflies have an adult life span of around two weeks.
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