Fleas are prevalent in most areas of the country. In temperate and subtropical regions of the United States, fleas may be active throughout the entire year. In cooler areas of the country, fleas are more prevalent during the warmer months. Fleas are more than an annoyance and can cause serious health problems in both pets and people.
Biology and Behavior:
Fleas have four distinct and very different life stages. Adults are the only stage within the flea life cycle that infest animals. The adult flea species often known to attack both dogs and cats is the Ctenocephalides felis, more commonly referred to as the cat flea. These adults are specially adapted to thrive in animal fur, navigating quite easily on its host. The adult flea is small, about 1/16th of an inch long, and is typically dark, reddish-brown to black in color. Adults are parasitic, feeding on blood as their exclusive food source. Female fleas require blood to produce eggs and are capable of producing several hundred eggs in their lifetime.
Flea eggs are round and smooth like chicken eggs, but only about 1/50th of an inch in length. After the eggs are laid, they will sift through the fur of the host, landing on the substrate, the area where the host sleeps or rests. For pet owners, this means that pet bedding, couches, chairs, beds, etc., will be the focal point of a flea infestation.
The immature fleas, or larvae, usually hatch within one week. Larvae are very small and will only grow to approximately 1/5th of an inch in length. Larvae resemble small grayish white maggots and are covered with fine hairs that they can use to attach themselves to carpet fibers or other material for protection. The larvae live in carpets or organic matter outdoors and feed on the fecal material, or dried blood, of adult fleas as well as other debris. Larvae avoid direct light and will migrate to cool, dark protected areas. After completing larval development, a cocoon is formed.
Cocoons are formed by larvae from available surrounding materials which may include carpet fibers or sand. Because the larvae use available materials for cocoon building, the cocoons themselves are virtually invisible, blending into the substrate. Within the cocoon, the flea larva pupates and awaits appropriate environmental cues to emerge as an adult flea. Fleas within their cocoons are well-protected and are not affected by insecticides. Although the adult may hatch within a week, under adverse conditions, fleas may not emerge for weeks or months. However, when fleas detect the presence of a host through vibrations and the presence of carbon dioxide, mass emergences may occur when fleas attack any suitable host nearby.
Be sure to check back next month for the second part of this article on flea control by Dr. Deanna Branscome.