Metapleural glands (also called metasternal or metathoracic glands) occur only in ants. They produce and secrete antibiotics onto the surface of the ant's exoskeleton, which help to prevent the growth of bacteria, fungal spores and pollen grains on the ants and inside their nest.

It is possible that small or ineffective Metapleural glands in some species of ant (eg Atta. bisphaerica and A. capiguara) is the reason they are difficult to rear in captivity, although many ants that do not have metapleural glands at all can successfully be reared in captivity with no difficulty.