Cocoons are sticky, attracting dirt and debris which will easily camouflage them. Under optimal conditions, new adults are ready to emerge from their pupal cocoons within two weeks. They can, however, remain in their cocoons up to 12 months in the absence of a host or unfavorable climatic conditions. This ability of flea pupae to wait until a host arrives can result in a sudden increase of adult fleas when they emerge simultaneously from many accumulated flea pupae. As soon as the adult fleas emerge from the pupal case, they look for a host for their first blood meal.
Adults can live one to two months without a meal and can survive up to six months with one.
They are the only stage that lives on the host and feeds on fresh blood. The flea population has been building up all year long in the form of eggs, larvae, and pupae, but rapid development into biting adults cannot be completed until the temperature and humidity are optimal and host cues signal for adult emergence from the pupal cocoon. Associated Problems Flea bites cause irritation, but also serious allergies in animals and humans. Other more serious and less common problems are associated with the cat flea. Tapeworms are transmitted to a vertebrate host via ingestion of an adult flea carrying a tapeworm cyst.