myrmecophile

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An organism, such as a beetle, that habitually lives in the nest of an ant colony.

from The Century Dictionary.

• noun An animal or plant which lives in symbiotic or intimate relations with ants. The majority of myrmecophiles are arthropods, especially beetles.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Biol.) An organism such as an insect that habitually shares the nest of a species of ant.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An organism, especially an insect, that lives in close association with or shares a nest with a species of ant.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an organism such as an insect that habitually shares the nest of a species of ant