The blue-green–streaked wings of the swallowtail butterfly harbor an intricate optical system with a design reminiscent of the latest in light-emitting diode technology, researchers now report.

As butterflies go, the Eastern tiger swallowtail is pretty scary. Their caterpillars look more like stubby snakes, complete with a fake green head, faux black and yellow eyes, and an orange, forked, ...

The British swallowtail butterfly (Papilio machaon britannicus) is the U.K.'s only native swallowtail and its largest native butterfly. It's instantly recognizable by its striking light ...

The lime swallowtail butterfly — an invasive species that hails from Asia and which has damaged citrus trees throughout the Caribbean for nearly 20 years — has reached Florida. The butterfly is fairly ...