Butterflies are among nature’s most beautiful creations. For thousands of years, they have captivated and intrigued artists, writers, scientists, and others the world over.
Butterflies and moths are part of the insect order Lepidoptera (“scaled wing”). Moths are the evolutionary ancestors of butterflies, with a fossil record dating back at least 150 million years. About 100 million years ago, some moths became active during the day and also developed brighter colors. These characteristics proved successful and butterflies were born.
Butterfly colors are much more than just pretty patterns. Complex coloration helps butterflies identify prospective mates and, in some species, serves as a warning to predators of toxins in the butterfly’s body. Some sneaky butterfly species mimic these warning colors to avoid being eaten. Cryptic coloration fools predators by allowing a butterfly or caterpillar to hide in plain sight.
Like all insects, the butterfly has three body sections. The head is the command center, with a brain and organs for sight and smell and a long coiled proboscis that is used to suck fluids. Densely packed with flight muscles, the thorax has six legs and four wings. The abdomen contains the digestive, excretory, and reproductive systems.
Butterflies have a complicated life cycle called complete metamorphosis. Their bodies undergo major changes from one stage to the next. Each stage is separated by a molt, which involves shedding the skin of the previous stage.
- The adult female butterfly or moth lays eggs on leaves, stems or other objects usually on or near the intended caterpillar food.
- The caterpillar, or larva, is the growth stage in the life cycle of butterflies and moths. With powerful, razor-sharp jaws, these eating machines feed almost continuously on the host plant.
- During the pupa, or transition stage, tremendous change takes place. Tissue breaks down and is reordered to form the next stage of life.
- The adult is the colorful insect we usually see. During this stage, butterflies and moths find mates and complete their life cycle by producing eggs.
Plants are essential to all stages of the butterfly life cycle. Adult butterflies feed on the nectar of flowers and lay their eggs on the leaves of host plants. Once the eggs hatch, the caterpillars feed voraciously on the host plant, sometimes stripping its leaves in a matter of hours. For the Monarch butterfly, the preferred larval host plant for the caterpillar is Milkweed. In the Museum’s Butterfly Pavilion, the preferred nectar plant for adult Monarch seems to be the Mexican Sunflower.
California’s butterfly populations are showing signs of stress, primarily due to habitat loss. The Endangered Species Act currently protects thirteen species of California butterflies. In 2003, two additional species, the Hermes Copper and Thorne’s Hairstreak, were imperiled by wildfires that devastated their habitat. What can you do to help?