Most feed on fungi, others are carnivores and eat small arthropods such as bark beetles.

The only significant case of dispute may be the Pycnomerini, which is a small lineage of Zopheridae incertae sedis and was formerly considered an independent family like the "Colydiidae".

That treatment is almost certainly wrong, but whether these beetles should be placed in Zopheridae as an additional subfamily Pycnomerinae, or treated as tribe Pycnomerini – and if the latter, whether they are better included in the Colydiinae or the Zopherinae – is still disputed.

The species Xylolaemus sakhnovi was described in 2014 from a fossil preserved in Baltic amber, which dates to the Middle Eocene.

[6] The extinct genus Paleoendeitoma, belonging to the extant tribe Synchitini is known from the Cenomanian aged Burmese amber of Myanmar.