Butterflies are a group of insects that fly during the day and belong to a general clade of Lepidoptera called the Phoenixidae. There are 7 families with about 18,800 species. Like other insects, butterflies are also arthropods, with segmented exoskeletons on the body surface, adult bodies are also divided into three parts: head, thorax and abdomen, and two pairs of wings on the chest, and various colors and markings on the wings are composed of scales on the wings. Butterflies are completely metamorphosed insects whose life includes four stages: egg, larvae, pupae and adult.
Recently, an international collaborative study revealed the origin and evolutionary history of butterflies, mapped a comprehensive butterfly "family tree" and discovered how they adapted to different environments and climate changes, thus conquering all parts of the world.
Originated in North America - coexisted with dinosaurs
According to the study, the earliest butterflies appeared in North America about 101 million years ago, in the age of dinosaurs. These primitive butterflies belong to the family Hedylidae and are the only primitive taxa still in existence. Their common ancestor with other modern taxa is an insect called Aethaloptera, which has long, thin beaks suitable for sucking pollen or spores.
From there, many taxa not only returned to North America, but also spread to Australia through Antarctica. At that time, the three continents were also connected to form the southern continent of Gondwana, a remnant of the ancient supercontinent Gondwana.
Reach Australia – and the rest of the world
The first two clades of butterflies to reach Australia through Antarctica were the subfamily Coeliadinae (about 72 million years ago) and the subfamily Euschemoniinae (about 65 million years ago). The subfamily Cerambycinae is a group of butterflies found only in Australia, with only one living species, Euschemon rafflesia, remaining in the rainforests of the East Coast.
To reach Australia, butterflies must have once lived in Antarctica during the Late Cretaceous and Early Paleogene, when global temperatures were much warmer than they are now. They must have crossed the continent to reach Australia 34 million years ago, before the two continents separated.
Other butterfly taxa entered Australia later through islands in Southeast Asia. They had earlier entered Asia from North America via the Bering Land Bridge. From there, they quickly took over land, spreading and diversifying into Southeast Asia, the Middle East, and the Horn of Africa. They even reached India, which was then an isolated island surrounded by the sea.
The most successful and diverse of these butterfly taxa is the family Papilionidae, which includes some of the largest and most beautiful butterflies, such as phoenix butterflies, iris butterflies, and mandarin duck butterflies. They entered Asia from North America about 60 million years ago and diverged into three main clades about 50 million years ago: Papilioninae, Parnassiinae, and Baroniinae.
Among them, the subfamily Pinnae is a group of butterflies adapted to the alpine environment, mainly distributed in the Himalayas, the European Alps and the Rocky Mountains of North America. They have a special wing shape and color, as well as physiological mechanisms that resist cold.
The subfamily Baronia brevicornis, on the other hand, is a group of extremely rare and mysterious butterflies, with only one living species, Baronia brevicornis, found only in the dry mountains of southwestern Mexico. They have distinctive long horns and a thick beak, probably to feed on certain special plants.
Adapt to different environments – and climate change
In addition to geographical diffusion, butterflies have demonstrated resilience to different environments and climate change. For example, about 40 million years ago, global temperatures began to drop, causing many plant taxa to become extinct or decrease. This is a huge challenge for insects that rely on plants for their food source.
However, some butterfly taxa have been able to take advantage of this change and find new food sources. For example, the subfamily Danainae and Parnassiinae have increased their defenses by feeding on plants that contain toxins or other chemicals. Lycaenidae, on the other hand, began to symbiosis with insects such as ants, jumping worms and shellworms for additional nutrients or protection.
In addition, about 25 million years ago, global temperatures dropped again and an ice age occurred. This led to the extinction or migration of many flora and fauna. However, some butterfly taxa are able to survive in cold environments and develop some special adaptations. For example, there are species in the family Pieridae that produce antifreezes to prevent body fluids from freezing. Some species in the family Nymphalidae are able to go into hibernation to survive the cold season.
By sequencing and comparing the genomes of more than 400 living and extinct butterfly species worldwide, the study sheds light on their evolution and spread over millions of years. They not only witnessed the rise and fall of life forms such as dinosaurs, mammals, and plants on Earth, but also demonstrated an amazing ability to adapt to different environments and climate changes. They are among the most beautiful, diverse, and successful creatures in nature.
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