Termites are a group of eusocial insects which consume a variety of decaying plant material, generally in the form of wood, leaf litter, and soil humus. They are distinguished by their beaded (moniliform) antennae and the soft-bodied, unpigmented worker caste for which they have been commonly termed "white ants"; however, they are not ants but highly derived cockroaches; they are genetically closer to some cockroach groups than these are to other cockroaches. About 2,997 extant species are currently described, 2,125 of which are members of the family Termitidae.