Butterflies live four lives: egg, caterpillar, pupa, adult
Butterflies of superfamily Papilionoidea wear large, often vivid wings that commonly fold at rest. As holometabolous insects they pass egg, larva, pupa and winged adult. Tropics may see several generations yearly; cold places may need years for one.
The English word goes back to Old English butorflēoge, and matching forms in Old Dutch and Old High German show it is old, even though modern Dutch says vlinder and German Schmetterling. One theory ties the name to the butter-yellow male brimstone; another to the insects flitting over meadows during the spring and summer dairy season. The order name Lepidoptera combines Greek words for scale and wing, a nod to the tiny scales that tile all four wings. Melanins supply blacks and browns and flavones some yellows, but many blues, greens and iridescent sheens come from the microscopic architecture of the scales rather than pigment.
Butterflies descend from moths, so they form a single clade while moths do not. The oldest known fossil butterfly, the skipper Protocoeliades kristenseni, comes from Denmark's Fur Formation and is about 55 million years old, and molecular clocks point to a Late Cretaceous start. Around 20,000 species fall into seven families, spread over every continent but Antarctica. Most fly by day, have clubbed antennae, and hold their wings upright over the body, unlike typical night-flying moths.
A female commonly lays one to two hundred eggs, each armored by a ridged shell called the chorion, waxed against drying, and pierced at one end by micropyles that let sperm in. A quick-setting glue fixes most eggs to a leaf, though Agathymus simply drops them at the base of the plant. Caterpillars spend nearly all their time eating leaves, yet a few hunt: Spalgis epius eats scale insects and Liphyra brassolis devours ant larvae. Unlike a moth pupa, the chrysalis has no silk cocoon. Adults may survive anything from a week to almost a year, and the Melissa Arctic spends two winters as a caterpillar.
Painted ladies and monarchs migrate across generations, with no single insect finishing the journey. Eastern North American monarchs fly thousands of miles to winter in Mexico, while British painted ladies make a 14,000-kilometer circuit between tropical Africa and the Arctic Circle over up to six generations. They steer with a sun compass corrected for time of day and can read polarised light, so overcast skies do not stop them.
Source: Butterfly
