Seaweed is a plant, right? And many plants depend on pollination for reproduction. So how is seaweed able to reproduce?

The trail does lead to the process familiar to many land plants. First, scientists discovered in 2016 that zooplankton can pollinate seagrass in the Caribbean. Now scientists have found a small, bug-like crustacean called Idotea balthica that can pollinate red seaweed, a type of algae that grows in tide pools.

At first glance, these relationships may seem to benefit only the plants, but the pollinators may be getting something too, like a safe place to hide from predators and a source of food.

In addition to furthering our understanding of undersea life, this news also raises an interesting question — did animal-mediated pollination first evolve underwater, instead of on land? Or did pollination evolve separately in both environments? “Until recently, fertilization with the help of animals was believed to have emerged among plants when they moved ashore 450 million years ago,” says Myriam Valero, a biologist at Sorbonne University and one of the study’s authors. “Red algae arose over 800 million years ago and their fertilization via animal intermediaries may long predate the origin of pollination on land. However, we cannot rule out that different animal-mediated fertilization mechanisms evolved independently and repeatedly in terrestrial and marine environments.”

This latest study, which is the first to document animal fertilizing seaweed, “really shakes up our understanding of how seaweeds reproduce,” says Jeff Ollerton, an ecological scientist and the author of Pollinators and Pollination: Nature and Society, but was not involved with the study. “This type of interaction may have been going on long before plants ever evolved and using a third party for reproduction may have much deeper roots than we ever realized,” he says.

Taken from “These Pollinating Crustaceans Are the Bees of the Sea” by Sarah Kuta (https://www.smithsonianmag.com/smart-news/these-pollinating-crustaceans-are-the-bees-of-the-sea-180980499).