Certain (but not all) strains of honey-bees (Apis species) in which workers remove the rotting remains of larvae that have died, thus preventing the spread of infection and mite infestation. The workers are 15–20 days old (i.e. middle-aged and typically younger than foragers) and are able to detect a dead larva, uncap its cell, and remove the larva and throw it out of the hive.
http://www.honeybeeworld.com/misc/hygienic.htm Information about hygienic strain and test for hygienic behaviour.
Subjects: Zoology and Animal Sciences.