The Ants That Sew Leaves Together

The ants pull a leaf into position. Then they pick up their own babies and use them as tools.

Weaver ants live in the canopies of tropical Asia, Africa, and Australia. Their nests are made of green leaves stitched into hollow footballs that hang from branches. To make one, a chain of adult ants grabs the edges of two leaves and pulls them together, sometimes forming living bridges of dozens of workers linked jaw to abdomen across a gap.

Then another group fetches the larvae.

A weaver ant larva produces silk from a gland near its mouth — silk normally meant for its own cocoon. Adult ants discovered, somewhere deep in evolutionary time, that if you gently squeeze a larva and tap it against a leaf edge, it secretes silk on cue. So the workers carry the larvae back and forth across the seam like living needles, gluing the leaves shut with thread the babies are forced to spend.

The larvae do not get to use the silk on themselves. They pupate naked in the finished nest. The colony has effectively reassigned every child's personal building material to the construction of the family home.

A mature weaver ant colony can hold up to half a million workers across hundreds of leaf nests spread through a single tree. They coordinate raids on intruders with chemical signals, recruit nestmates in seconds, and patrol territories so aggressively that farmers in Vietnam and China have used them as living pesticide for over a thousand years. A 4th-century Chinese text describes citrus growers buying nests at markets and tying bamboo bridges between trees so the ants could spread.

That is one of the earliest recorded uses of biological pest control on Earth. It involved an insect that had already invented textile manufacturing, child labour, and a working postal system.

Humans figured out sewing roughly forty thousand years ago, with bone needles. Weaver ants were doing it before we existed as a species.

Their needles just happen to be alive and complaining.