Butterflies: Warming Up
It can get pretty toasty in the Butterflies Live! exhibit, especially on those hot summer days. While we (humans) might think it’s too hot, the butterflies love it and actually need it. In fact, butterflies can’t even fly if their body temperature is less than 86 degrees Fahrenheit! Butterflies are cold blooded (ectothermic) and have no means for regulating their body temperatures. Instead, they have to rely on behavioral instincts to warm their bodies up in order to fly, also known as thermoregulation.
One way the butterflies do this is to bask in the sun, called dorsal basking. You can usually find them resting with their wings open on a sunny spot on our stone floor or a nice, big leaf by the window. Think of this activity like a solar panel. The butterflies are using the surface of their wings to soak in and absorb the heat from the sun to give them energy. While most butterflies do this, some butterfly families use the underside of their wings to absorb heat called lateral basking. These include the clouded yellows (Colias croceus) and green hairstreaks (Callophrys rubi) who always rest with their wings closed. Lateral basking includes a system of tilting one side of the wings towards the sun and switching sides when they get too hot.
Besides basking, butterflies take part in another behavioral strategy called shivering. This is exactly what it sounds like. Butterflies will rapidly shake or shiver in order to raise their body temperatures to prepare for flight. This heats up the thorax (abdomen) and helps them fly a short distance. While warming up can be difficult, butterflies can also get too hot! So sometimes they will seek shelter under leaves and on tree trunks to cool down.
We try our very best to create an ideal temperature and humidity level that mimics our tropical butterfly species’ natural environments. But don’t let the heat keep you away, stay hydrated and drink lots of water so you stay cool and can enjoy our butterflies.