Inquilines

Definition

Organisms that live commensally within the nest, burrow, or constructed dwelling of another species without causing measurable harm to the host. Inquilines typically exploit the physical shelter, microclimate, or food resources of the host's home, distinguishing them from parasites (which reduce host fitness) and social parasites (which manipulate host social behavior, often aggressively). The relationship is generally considered commensal, though the fitness impact on hosts remains difficult to quantify and may vary contextually.

Etymology

From Latin inquilinus, 'tenant' or 'lodger', from in- 'in' + colere 'to dwell'.

Example

The rove beetle genus Myrmecophilus (Staphylinidae) contains numerous ant inquilines that inhabit formicid nests, feeding on detritus and regurgitated food without directly attacking the colony; similarly, certain termitophilous silverfish (Lepismatidae) occupy termitaria, moving freely among host castes.

Synonyms

• nest commensals
• nest associates

Related Terms

• commensalism
• social parasitism
• kleptoparasitism
• myrmecophile
• Termitophile
• guests
• nest fauna

Usage Notes

The boundary between inquilinism and parasitism is often ambiguous in practice. Some specialists restrict 'inquiline' to species with no demonstrated negative host effect, while others use it more broadly for any nest-dwelling non-host. In myrmecology and termitology, the term frequently appears in contrast to 'social parasites' (e.g., slave-making ants, parasitic ant queens) and 'predators' that attack colonies from outside. Not all nest inhabitants are inquilines: scavengers that only opportunistically enter nests are sometimes distinguished as 'casual guests' or 'synechthrans'.