Fleas are pests of humans and their domestic animals all over the world. Fleas are ectoparasites, meaning they feed on the outside of the host. While most fleas prefer non-human hosts, many can and do feed on humans when infestations are heavy or when other hosts are not available.
Fleas are small, wingless insects which average 1/12 to 1/6 inch long, but can vary from as small as 1/25 to 1/3 inch long. Fleas have a complete metamorphosis (the fleas development consists of egg, larva, pupa or cocoon and adult). The flea larva are small, active, worm like creatures. They feed on all types of organic debris, and develop especially well when they can feed on the feces of adult fleas.
The larva grows through 3 “molts” in about one week or up to several months, depending on environmental conditions and food availability. A mature larva will be about 1/8 to 1/6 inch long. The mature larva spins a cocoon for pupation. If temperatures are favorable, about 70 decrees F, within about 7-10 days the pre-adult flea develops within the cocoon, but the adult may not emerge immediately.
Many adult fleas emerge from the pupa within 7-14 days, but some may not emerge for several months. Warm and humid conditions, the presence of carbon dioxide ( exhaled from warm blooded host) and the mechanical signals ( vibrations of nearby footsteps or the weight of a pet stepping on the cocoon) will trigger emergence.
Cat and dog fleas are the most common species occurring throughout the United States. While both species prefer cats or dogs as hosts, they can also be found feeding on rodents, livestock and humans. Cat fleas, by far, are the more commonly encountered of the two species in pest control work in and around homes. They prefer locations where dust and organic debris accumulate, and are commonly found in houses, under houses and, if temperature and humidity levels permit, in yards.
Fleas control involves actions from both the home owner and the pest control professional. The home owner should treat all animals (preferably by a veterinarian) and then vacuum the areas identified by the pest control professional. The treatment should include an adulticide and an insect growth regulator. After the treatment, it is not uncommon to see some fleas still active because there is no insecticide that will kill the pupae or the eggs present at time of treatment.
The fleas emerging from the pupa after the treatment will be controlled by the residual adulticide treatment and the larvae hatching from the eggs will be affected by the I.G.R. (insect growth regulator). Follow up services may need to be performed in very heavily infested situations.