Some ant nests contain a remarkable myrmecophilic (ant-loving) beetle called the "anteater scarab." It includes several species in the genus Cremastocheilus, in the large beetle family Scarabaeidae. Its common name is misleading because it apparently doesn't always eat ants. In fact, some ant species actually encourage this beetle to enter their nests. According to antwiki.org/wiki/Myrmecocystus, the symbiotic behavior of this beetle within the host nest is complicated and quite variable. Cremastocheilus may coexist with, but not necessarily be harmful to the ant colony. The following terms describe some of the beetle's relationships with the ant colony: Synechthran: A persecuted intruder (a scavenger, parasite or predator that is treated with hostility by the host colony); Synoekete: Indifferently tolerated guest (a symbiont that is treated with indifference by the host colony); Symphile: Amicably received guest (a solitary insect or other arthropod that is accepted by the ant colony and treated amicably); or Predator: Intruder that feeds on ant larvae.

Some wasps inside the syconia of figs are called inquilines, coexisting with, but not necessarily harmful to the fig or its symbiotic wasp. An inquiline can be defined as an animal that lives commensally in the nest, burrow, or dwelling place of an animal of another species. Symbiosis may be defined as an intimate association between two or more organisms. There are three main types of symbiosis, including commensalism, parasitism and mutualism. In commensalism, one organism in the relationship is benefited while the other is neither benefited nor harmed. If I were still teaching biology these terms would be great choices for crossword puzzles or multiple choice and matching quizzes!