Sea slug species uses never-before-seen type of predation

Some sea slug species use a form of predation that has never been recorded in any other animal species.
By Jason Spencer | Nov 07, 2017
A sea slug species that lives near the bottom of the ocean has shed light on a brand new hunting technique, known as kleptopredation.

Typically, nudibranchs -- a family of colorful sea slugs -- feast on a coral-like super organisms known as hydroid colonies. Such colonies are made up of a wide collection of individual polyps that capture and eat both plankton and small crustaceans.

In the study, a group of researchers from the University of Portsmouth discovered that, despite common belief, the slugs do not eat randomly. Rather, they prefer to prey on polyps that have recently consumed a large meal. That then allows them to both feast on the polyp and the food that polyp just are.

"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," explained lead author Trevor Willis, a senior lecturer at the University of Portsmouth, according to UPI.

This type of predation is completely unique and has never been recorded before. Some species show kleptoparasitic behavior -- when one species takes food killed by another -- but that is not directly stealing food through consumption. In this case, the predator is eating both its own prey and the prey that animal had captured.

Researchers first found this behavior during a study aimed to look at the consumption patterns of nudibranchs. As they only eat one organism, the team worried the slugs might eat their way out of existence by depleting their only source of nutrients.

However, the study shows that hydroid polyps only make up a small percentage of the sea slug's diet. Nudibranchs mostly eat zooplankton, which they get through consuming hydroid polyps.

These findings could lead to a new understanding of sea slugs and shed new light on animal behavior. Though this predation has only been noted in nudibranchs, there is a chance other species employ it as well.

"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," added Willis, in astatement.

The new research is detailedin the journal Biology Letters.


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