Microplastics Disrupt Hermit Crabs' Ability to Choose Shells

BELFAST, NORTHERN IRELAND — A study published in the journal Biology Letters has found that exposure to microplastics can disrupt a hermit crab's ability to choose a shell.

Researchers from Queen's University Belfast and Liverpool John Moores University placed 29 female hermit crabs into a tank containing microplastics. A control group of 35 crabs was placed into a tank with no microplastics.

After five days the crabs were moved into lower-quality shells and presented with the option to choose a higher-quality shell. Only nine of the crabs that had been exposed to microplastics moved into the new shells, compared to 21 from the control group.

This suggests exposure to microplastics impairs the crabs' cognition, and that microplastics in general can have important effects on an animal's behavior.

Gareth Arnott, co-author of the new research from Queen's University Belfast, told the Guardian he was surprised by the results. "We hypothesize that either some aspect of the polyethylene is getting into them to affect their decision making, or else it is an indirect effect that the presence of the plastic in the tank might be influencing their feeding behavior, for example," he said.