Cockroaches groom to improve their sense of smell, scientists say.
The insects are known to manipulate their antennae, the protrusions on their head which they use to sense the smells, temperature and physical layout of their environment.
US researchers found that the cockroaches groom to wipe away secretions that would otherwise interfere with their sense of smell.
They also identified the same behaviour in carpenter ants and houseflies.
The findings are published in the journal Proceedings of the National Academy of Sciences.