Sticky new creature — known as ‘assassin’ — coats itself before attacking, study says

A tiny new creature has been discovered in Australia that puts its prey in a sticky situation.

The creature is a type of assassin bug that employs tools to hunt, an uncommon phenomenon in animals, according to a study published on April 26 in the journal Biology Letters.

Found in the grasslands of western Australia, the insect appears exclusively on or near spinifex hummocks, a desert bush that produces a gooey resin, researchers said.

The black-and brown-colored insect, named Gorareduvius sp., appears to undertake a “meticulous,” multi-step process of collecting and coating itself in the plant’s resin, Dr. Fernando Soley, a co-author of the study and postdoctoral fellow at UCLA, told McClatchy News.

The process goes like this: “First scrape it, then accumulate it, and finally spread it all over its body, even its eyes,” Soley said.

Upon observing documenting the previously undocumented creature’s peculiar coating behavior, researchers set about creating an experiment to determine whether the insect was using the resin to hunt.

As part of the experiment, 26 assassin bugs were captured in vials and transported to a campsite where they could be observed attacking prey under artificial conditions.

At the campsite, the insects were placed in cylindrical arenas outfitted with holes in the floor that prey could be introduced through.

These miniature colosseums hosted 129 staged interactions between Gorareduvius bugs — some which were coated in resin and others which were not — and two types of prey: flies and ants.

Through the course of the staged hunts it was observed that the insects equipped with resin were more successful in capturing their prey than their unarmed counterparts.

The probability of success went up by 26% when Gorareduvius bugs were coated in resin, likely because the gooey substance slowed down the prey.

“Prey never appeared to be fully stuck to the resinous surface of the assassin bugs,” researchers said. “Rather, it appears that brief, temporary adhesion delayed prey responses sufficiently enough for the assassin bugs to grasp and stab their prey.”

The assassin bug’s implementation of resin as a tool did not appear to be a learned behavior because all individuals, even those that were newly hatched, engaged in the practice, researchers said.

This type of innate usage is referred to as stereotyped or “hard-wired” behavior.

“Stereotyped tool use is uncommon and I would say that stereotyped tool use that involves several behavioral steps to properly use the tool … is even more uncommon,” Solely said.

This story was originally published May 9, 2023 at 2:43 PM with the headline "Sticky new creature — known as ‘assassin’ — coats itself before attacking, study says."