After two cold nights where temperatures dipped into the 30° Fahrenheit range, I didn’t expect to see many butterflies in my garden the following mornings. However, as soon as the sun came out and temperatures rose to 60° Fahrenheit and above, it seemed that Cloudless Sulphurs and Gulf Fritillaries appeared out of nowhere.
On a day-to-day basis butterflies must adjust to weather conditions—heat, cold, wind, and rain—in order to survive. Being cold-blooded, their bodies naturally conform to the temperature of the air around them. This temperature, however, is not always warm enough for them to fly to find food, escape predators, and reproduce so they must somehow warm themselves to their ideal temperature of 80–100 degrees Fahrenheit.
Basking in the sun is the primary means by which butterflies warm themselves. Dorsal baskers such as Gulf Fritillaries stretch their wings out flat towards the sun while lateral baskers such as the Cloudless Sulphurs keep their wings closed and turn sideways to the sun. Body baskers angle their wings sharply overhead to direct the solar heat to the body. Some butterflies press their wings close to the ground, a rock, a leaf or other structures so that warmth is also received through conductive heat.
On cool mornings especially in the fall, look for butterflies in small spaces of higher temperatures called microclimates. For butterflies, suitable microclimates would be sunny spots out of the wind where the sun’s heat is intensified. Brick buildings, for example, receive radiant heat from the sun and conduct it to the surrounding area. On a cool morning, put your hand on sunny bricks and feel the warmth. In addition, if yellow butterflies such as Cloudless Sulphurs can find a warm, protected microclimate, hang upside down, and bask on shrubs that have leaves turning yellow in the fall, the butterflies will also be camouflaged and thus avoid bird predation.
Microclimates around your home may change with the changing light of day. These microclimates are hardly noticeable in themselves, but when you look at the world through butterfly eyes you will notice them quite readily!
©Rita Venable 2012
