New Microscope Shows Coral Colonies Kissing, Fighting and Eating

Two polyps connect their gastrovascular openings at night, a behavior that has never been documented before. Dubbed ‘polyp kissing,’ this behavior likely allows the polyps to exchange materials, such as food.

Scientists injected Artemia, a brine shrimp, near the coral and captured a time-lapse video of communal feeding between two neighboring polyps. The two polyps work together by intertwining their tentacles to digest their prey.

Two different loose corals colonies, Stylophora on the left and Pocillopora on the right were placed close together to induce competition. When corals compete for dominance, they emit mesenterial filaments, string-like structures, which they use to attack and, ultimately, digest their rival.

Here, the Platygyra, on the left, has attacked and is beginning to digest the Stylophora, on the right. Scientists found that competition response times and attack mechanisms differed depending on the coral. When a Platygyra was placed next to one of its own kind, for example, it did not attack at all.

A Platygyra colony extends its filaments when exposed to a net filled with brine shrimp, right. Colonies were exposed to a number of different stimuli in order to record their responses.