"Snow bugs" dance softly across the autumn skies of Hokkaido. When you see them, many people probably think, "The first snow is coming soon." In fact, "snow bugs" are not an official name, so what exactly are they? Also, is it true that Hokkaido residents often say, "When snow bugs fly, the first snow will fall?" We'll explain the truth in an easy-to-understand way.

The true identity of snow bugs is the "Todononeowatamushi"

What is commonly called "snow bugs" is actually a type of aphid called the "Todononeowatamushi." When they reach adulthood, they are covered in waxy white fluff and fly around lightly, hence the name "snow bugs," meaning "snow bugs."

The snow bugs are born in the Japanese ash tree in spring and settle in the Japanese ash from summer to the beginning of autumn. They feed on the Japanese ash tree and undergo several generations over the course of a year, and at the end of autumn, the winged adults migrate to the Japanese ash. In other words, the snow bugs we see are adult Japanese ash bugs in the process of migrating from the Japanese ash to the Japanese ash.

A unique survival strategy unique to weak insects

The Todononeowowa aphid is known as a "weak insect" and has no way to fight off predators, so it is rapidly eaten. However, a major feature that allows it to resist predation is its morphology, known as a "stem mother."

As they molt repeatedly, they become females called "mothers," who give birth to genetically identical clones of female larvae, which then give birth to clones and multiply. One female gives birth to approximately 150 larvae, so they have survived by continuing to give birth to more than that number despite being preyed upon.