Nov. 1 (UPI) -- In studying the plunderous ways of sea slugs, scientists have discovered a new way to catch a meal -- a technique called kleptopredation.
As new research shows, sea slugs are the pirates of the seafloor, attacking prey in their post-meal malaise in order to steal the meal their target just consumed.
"This is very exciting, we have some great results here that rewrite the text book on the way these creatures forage and interact with their environment," Trevor Willis, a senior lecturer at the University of Portsmouth, said in a news release.
Nudibranchs, a family of brightly colored sea slugs, snack on hydroid colonies, a coral-like super organism. The colonies consist of a collection of individual polyps which capture and eat plankton and small crustaceans.
When researchers analyzed the feeding habits of the colorful sea slugs, they found the gastropods prefer to consume polyps that have recently eaten a healthy helping of zooplankton.
"Effectively we have a sea slug living near the bottom of the ocean that is using another species as a fishing rod to provide access to plankton that it otherwise wouldn't have," Willis said.
The predation technique is new to biology.
"People may have heard of kleptoparasitic behavior -- when one species takes food killed by another, like a pack of hyenas driving a lion from its kill for example," Willis said. "This is something else, where the predator consumes both its own prey and that which the prey has captured."
Willis set out to study the consumption patterns of nudibranchs after he became intrigued by their specialization. By adopting such an exclusive diet, Willis was concerned the sea slugs could eat their way out of existence by depleting their sole source of nutrients.
But the latest research -- detailed in the journal Biology Letters -- suggests hydroid polyps only make up a small percentage of the sea slug's diet. Nudibranchs mostly eat zooplankton -- zooplankton caught and consumed by hydroid polyps, of course.
"Our ability to understand and predict ecosystems in the face of environmental change is impeded by a lack of understanding of trophic linkages," Willis said. "While we have some great results, like any science worth its salt, it raises more questions than it answers."