From the team at BBC Wildlife Magazine

Isopods found to fertilise seaweed in our oceans

Bees of the sea: a new study reveals that marine crustaceans called isopods are fertilising seaweed.

Isopod against a black background.
Published: September 21, 2022 at 11:02 am
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Biologists have discovered that slender wart weed, a red seaweed that grows in shallow UK waters, is ‘pollinated’ by a woodlouse-like marine crustacean named Idotea, which transports the spermatia – the algal equivalent of pollen – from male to female plants.


“When we found these crustaceans were highly associated with the algae, particularly Myriam Valero, a scientist at CNRS, the French national research agency during the reproductive season, that’s when we thought that maybe they are helping with fertilisation,” says Myriam Valero, who led the research from France’s University Paris- Sorbonne.

In return for their services, the crustaceans find food and shelter among the seaweed’s fronds. While the sex cells of many seaweeds are able to swim using tail-like flagellae, those of red algae lack any form of propulsion.

Without the crustaceans’ help, the seaweed’s sex cells would be at the mercy of currents. “Although red algae are very different to flowering plants, in a way these systems are very similar,” says Valero. “We are now looking at another red alga species in Chile, where there are no Idotea present, but there is another crustacean species that might be performing a similar role.”

Red algae are an ancient group of plants, raising the possibility that they enlisted the services of invertebrate ‘pollinators’ long before flowers appeared.


Main image: Idotea balthica. © E. Lazo-Wasem, via Wikimedia Commons


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