Mysterious Evolution of Butterflies

Butterflies

Summary

Butterfly evolution is the origin and diversification of butterflies through geologic time and over a large portion of the Earth’s surface. The earliest known butterfly fossils are from the mid Eocene epoch, around 50 million years ago. Their development is closely linked to the evolution of flowering plants, since both adult butterflies and caterpillars feed on flowering plants. Of the 220,000 species of Lepidoptera, about 45,000 species are butterflies, which probably evolved from moths. Butterflies are found throughout the world, except in Antarctica, and are especially numerous in the tropics; they fall into eight different families.

Genetic

The butterflies form the clade American Moth-Butterfly family, which is composed of three superfamilies: Hedyloidea (the moth butterfly family Hedylidae), the Hesperioidea (the skipper family Hesperiidae), and the Papilionoidea (the true butterfly families Papilionidae, Pieridae, Nymphalidae, Lycaenidae, and Riodinidae). All of these families are monophyletic. The Hedyloidea is the sister group to the other two superfamilies. Within the Papilionoidea, Papilionidae is the sister group to the other families, and Pieridae is the sister group to (Nymphalidae+(Lycaenidae+Riodinidae)). Phylogenetic hypotheses within the Nymphalidae are still under discussion. Current research is concentrated on subfamilial and tribal relationships, especially in the Nymphalidae.

Fossils

The wispy, delicate nature of butterflies and moths is part of their charm, but their soft bodies do not preserve well in the fossil record, posing a problem for scientists. However, Butterfly fossils have been well covered by Grimaldi & Engel (2005), who point out their weakness in resolving the sister group of the Rhopalocera: butterflies of ’45 My’ are much like their living counterparts. The first fossil was formed around 40-50 million years ago.

Evolution

Butterflies developed during the Cretaceous Period, often called the “Age of Flowering Plants,” 65 million to 135 million years ago—a time when dinosaurs also roamed the earth. Imagine a brightly yellow-colored butterfly landing on the back of a Tyrannosaurus rex. Well it may have happened. That means that moths and butterflies are much older than previously thought.

Evolution suggests that back then butterflies were unlikely to have been a bright yellow. It’s thought they were not brightly colored at all. They were a browny-grey, more like a moth than a butterfly of today. The sparkling butterflies that we think are so beautiful came much later.

Evolutionary relationships among major Lepidopteran groups are not well understood. What we do know is that, despite the attention they receive from scientists and the public alike, butterflies are not the pinnacle of Lepidoptera evolution. Lepidoptera is an order of insects that includes butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 families and 46 superfamilies, 10 per cent of the total described species of living organisms. It is one of the most widespread and widely recognizable insect orders in the world. The Lepidoptera show many variations of the basic body structure that have evolved to gain advantages in lifestyle and distribution.

One recent theory is that an obscure moth family, the Hedylidae, represents the nearest living relatives of the butterflies. This theory suggests that butterflies are just a group of brightly colored moths. There are still discoveries waiting to happen regarding the evolution cycle but we are sure that the butterflies are at least 100million years old, and they have evolved with the flowers as we know it.

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