Inzoology, aninquiline (fromLatininquilinus, "lodger" or "tenant") is ananimal that livescommensally in the nest, burrow, or dwelling place of an animal of another species. For example, some organisms, such as insects, may live in the homes ofgophers or the garages of humans and feed on debris,fungi, roots, etc. The most widely distributed types of inquiline are those found in association with the nests of social insects, especiallyants andtermites – a single colony may support dozens of different inquiline species. The distinctions betweenparasites,social parasites, and inquilines are subtle, and many species may fulfill the criteria for more than one of these, as inquilines do exhibit many of the same characteristics as parasites. However, parasites are specificallynot inquilines, because by definition they have a deleterious effect on the host species,[1] while inquilines have not been confirmed to do so.
In the specific case oftermites, the term "inquiline" is restricted to termite species that inhabit other termite species' nests[2][3][4] whereas other arthropods cohabiting termitaria are called "termitophiles".[5][6] It is important to reiterate that inquilinism in termites (Blattodea, formerlyIsoptera) contrasts with the inquilinism observed in other eusocial insects such asants andbees (Hymenoptera), even though the term "inquiline" has been adopted in both cases. A major distinction is that, while in the former the species mostly resemble forms ofcommensalism, the latter includes species currently confirmed as social parasites, thus, being closely related toparasitism.
Inquilines are known especially among thegall wasps (Cynipidae family). In the sub-family Synerginae, this mode of life predominates. These insects are similar in structure to the true gall-inducing wasp but do not producegalls, instead, they deposit their eggs within those of other species. They infest certain species of galls, such as those of the blackberry and some oak galls, in large numbers, and sometimes more than one kind occur in a single gall. Perhaps the most remarkable feature of these inquilines is their frequent close resemblance to the insect that produces the gall they infest.[7][8]
The terminquiline has also been applied to aquatic invertebrates that spend all or part of their life cycles inphytotelmata, water-filled structures produced by plants.[9] For example,Wyeomyia smithii,Metriocnemus knabi, andHabrotrocha rosa are three invertebrates that make up part of the microecosystem within the pitchers ofSarracenia purpurea.[10] Some species of pitcher plants like theNepenthes andCephalotus produce acidic, toxic or digestive fluids and host a limited diversity of inquilines. Other pitcher plant species like theSarracenia orHeliamphora host diverse organisms and depend to a large extent on their symbionts for prey utilization.[11]