Life cycle
Fleas undergo a complete metamorphosis. The adult female lays 4-8 eggs after each blood meal. In the lifetime of the female flea, she can lay several hundred eggs. Most eggs are laid on the host, and these usually fall off, they can be distributed in virtually any areas visited by the host animal. High concentrations of flea eggs are often associated with animal sleeping areas. Eggs usually hatch in 2-14 days. Larvae feed on available organic materials, such as human skin scales and other debris that may accumulate in carpets, furniture, pets bedding, cracks between floorboards, lawns and gardens. Adult fleas often excrete almost undigested blood, which may dry into dark granules and serve as an important feeding supplement for larvae. These dark faeces should not be confused with the paler eggs. The feeding period for flea larvae is usually 15 days, but it can be as long as several months in adverse conditions. When feeding is complete, the larvae usually spin a silken cocoon, to which adhere particles of dust and soil, so as to camouflage and protect itself. The larva pupates within the cocoon, and the pupal stage may last for several days or up to a year. The entire life cycle may take a little as 18 days or more than a year in favourable conditions. Adult males and females, both bloodsuckers, may live 100-500 days and can endure long periods without food.
Habits
Fleas prefer warm, humid conditions and hence are often a pest in the summer months. High humidity favours the development of larvae, which may be populous indoors and outdoors, where there are sandy soils, and particularly if under cover out of rain. When climatic conditions are favourable, the development of larvae outdoors can be very widespread. Insects can slow and almost halt their growth and development at various stages in order to make the most of more favourable conditions. Flea pupae may remain as pupae for long periods, being stimulated to emerge as adults by vibrations. This can happen after a flea treatment has been done, when the home owner uses the vacuum cleaner this will trigger the pupa to emerge as adults. This is a survival tactic for a flea as they will only become adults when there is a blood meal so they can repeat the cycle. As the pupa there energy is minimal, a lot less than that of an adult flea, which moves more and consumes more oxygen. Building that have been vacant for some time can become alive with fleas when humans enter, this is a typical case in the rental market as tenants leave and there is sometime between the next tenant, when the new tenant moves in they get bitten by the fleas.
Fleas as a pest
The pest status that fleas have achieved is largely due to their biting and blood sucking this can cause severe irritation and even transmit disease. Fleas are troublesome in domestic and commercial premises indoors and outdoors.