Endophily

Endophily is the behavioral tendency of certain insects, particularly disease vectors such as mosquitoes, to rest indoors or on indoor surfaces after feeding, rather than outdoors. The term is commonly used in vector biology and is often contrasted with exophily, which describes outdoor resting behavior, and with endophagy or exophagy, which describe indoor or outdoor feeding, respectively. The degree of endophily can vary by species, geographic region, season, and housing conditions.

Endophily has clear implications for disease transmission and control. Vectors that rest indoors after biting are more likely to come into contact with indoor control measures such as insecticide-treated nets and indoor residual spraying, potentially reducing transmission. Conversely, strongly exophilic species may evade such interventions and require outdoor or community-wide strategies. Understanding a species’ endophilic tendency helps guide surveillance, risk assessment, and the allocation of control resources.

Assessing endophily involves methods that sample indoor resting populations, including indoor aspiration of resting mosquitoes, resting boxes placed inside homes, and indoor exit or spray-catch traps. Indices describing the proportion of a population found resting indoors are used to compare species, sites, and time periods. Environmental factors, housing quality, and human behavior can influence observed endophily, and populations may shift in response to vector-control pressures.

Endophily is a key concept in epidemiology and public health, helping to tailor interventions and improve understanding of how vector behaviors shape disease dynamics.