Giant Sea Anemone Also Eats Ants, Spiders: How Did These Insects Reach the Sea?

Sea anemones are soft-bodied underwater predators that are famous for their bright colors, and tentacles that look like flowers. They also eat almost anything that they can catch in their mouths. However, a recent analysis of the gut contents of a giant plumose anemone reveals a surprising part of their diet that has not been recorded before.

The study, "DNA metabarcoding provides insights into the diverse diet of a dominant suspension feeder, the giant plumose anemone Metridium farcimen" published in the journal Environmental DNA, provides an in-depth look into the diversity of prey that the giant plumose anemone has been catching.

Giant Sea Anemone Also Eats Insects

The study focused on the giant plumose anemone Metridium farcimen found in the sides and undersides of floating docks in San Juan Archipelago in the northwestern part of Washington D.C.

Science Daily reported that researchers used DNA metabarcoding to identify the gut contents of the giant sea anemone and found that they were mostly composed of anthropods, like crabs, and also barnacles, copepods, and insects.

Study first author Dr. Christopher Wells, a postdoctoral researcher from the University at Buffalo Department of Geology said that the giant sea anemone has been eating whatever they can catch. But the surprising results showed that the anemone is not only eating marine plankton but about 10% of its diet consisting of ants, which are not marine creatures.

The giant plumose anemone looks a bit of a cauliflower, with its stalk-like column attached to rocks and other surfaces on or end, and a crown of tentacles on the other end. They use their feelers to collect and shove food into their mouths, which apparently include non-marine anils, like ants and occasionally or spiders.

"With DNA metabarcoding, you can identify what species' antennae that is. We were able to identify a lot more diversity using metabarcoding," Wells said as quoted by Science Daily.

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How Could the Giant Plumose Anemone Have Eaten Ants and Spiders?

According to the news release by Florida Museum, researchers dig deeper into the natural history of the insects that were found in the guts of the giant plumose anemone. They came up with a plausible explanation as to how these ants became part of the marine food chain.

Wells said that these pale-legged field ants spent most of their time underground, building and improving their colony. However, during the late summer, the queen and male ants equipped with wings from several colonies fly and congregate in dense swarms to mate, triggered by the warm temperatures and fair weather.

Unfortunately, these insects were not strong fliers as they were easily swept by the wind and far off course, which sometimes land them into the ocean. As much as they are not good fliers, ants are also not good swimmers and end up drowning and getting eaten by marine creatures, including sea anemones.

The findings of the study indicate that the giant plumose anemone could also eat spiders occasionally, and a few other insect species aside from ants that wander closer to the water's edge and drown.