When these flies develop indoors, it generally indicates a dead animal in the vicinity—for instance, maybe a rodent has died in the walls of the building from the use of a rodenticide. All it takes is one fertilized female to lay her eggs in a carcass, and a few weeks later a hundred flies emerge. These flies can detect an ideal laying site from a few kilometers away. Adults are strongly attracted to ultraviolet light and often live on pollen and nectar. Like many species of fly, these flies are significant vectors of disease.