These strange crustaceans fertilize algae like bees pollinate plants

Although the process of pollination by bees is well known, recent research has revealed a similar mechanism in the underwater world, involving red algae and tiny crustaceans.

Underwater bees

Published in the journal Science, this research was carried out by Emma Lavaut, doctoral student at the Sorbonne University and Myriam Valero, geneticist at the CNRS, in partnership with researchers from their institutes and the Austral University of Chile. Working from the Roscoff marine station, the team studied thered algae Gracilaria gracilisas well as marine isopods (called idoted) belonging to the species Idotea balthica.

The male gametes of Gracilaria gracilis being devoid of flagella (implying that they cannot swim and direct themselves as spermatozoa would), it was believed until now that this species of algae (being scientifically neither a plant nor an animal ) took advantage exclusively of underwater currents to disperse its reproductive cells from one individual to another.

Recent experiments and observations made by the study authors have shown that Idotea balthica played a key role in this process: when crustaceans fed on male specimens of G. gracilisspermatia (male gametes produced by structures dotting the surface of the seaweed) covered with mucilage (sticky substance emitted by many plants) attached themselves to the cuticles of these small sea creatures.

When these crustaceans (measuring a few millimeters long) then land on a specimen of female algae, part of the spermatia they carry is transferred to the female gametes, which completes the fertilization process. It’s a win-win relationship: protecting the idotas from the elements, the algae are also covered in the tiny organisms they love.

The origins of pollination disrupted

Such results suggest that pollination of plants by terrestrial insects may have evolved from a process that began under the ocean. Intervening on dry land for about 140 million years, it would have potentially started under the surface of the oceans much earlier (knowing that G. gracilis existed for about 800 million years).

Since underwater currents probably play a big role, the next step for the team will be to determine precisely the percentage of dispersal of gametes ensured by crustaceans.