Butterflies move by using their wing muscles to fly. However, butterflies cannot move if their wing muscles get too cold. Their bodies work most effectively at an internal temperature of approximately 82 degrees Fahrenheit. Butterflies must use their surroundings in order to maintain their body heat. During the day, butterflies bask with their wings open to absorb warmth from the sun.
In colder daytime temperatures, butterflies use their wings to reflect sunlight onto their thorax where the wing muscles are attached. Butterflies can also soak up heat from warm rocks by resting on them. If the sun still doesn't provide ample heat for a butterfly to move, the butterfly moves its wings in small increments, which will gradually warm its wing muscles, enabling it to fly. Butterflies frequently fly in short bursts on cool days because their bodies get colder during flight, as well as when cool breezes move over their wings. At night, butterflies roost to protect themselves from the cold. Some butterflies migrate, which is a trip over a very long distance. To make this type of trip, butterflies need to store energy and eat lots of food. The most famous migration is that of the Monarch butterfly.