When we think of pollination, we usually think of bees, bats or other flying foragers.

They visit male flowers to collect nectar and get covered in sticky pollen, which they carry to female flowers, in search for more nectar.

Marine plants also reproduce with pollen, but scientists thought water movement carried it from one plant to another. Then researchers discovered what they called “the bees of the seas.”

Small crustaceans crawl over the male flowers of seagrass to eat a nutritious substance produced by the flower and get covered in goo containing pollen—which they transfer to female flowers.

Seagrass is a land plant that evolved to live in the sea a hundred million years ago; maybe it’s not surprising to find it has a pollinator like other land plants.

But scientists have found another pollination relationship that may be far older.

Red algae are eukaryotes, not plants, having evolved separately and much earlier. Researchers recently discovered a microscopic creature called an isopod that eats organic material from the algae, gets coated in sticky spermatia, a kind of protopollen, and transfers it from male to female algae.

This discovery has scientists rethinking marine pollination. It may have evolved a billion years ago, one of the earliest sexual reproduction processes on Earth.

If so, what other Earth processes may be far older than we imagined?