Most flea cocoons live within carpeting. They can also be found on pet bedding or upholstered furniture. Outdoors, the cocoons may develop in dog houses, dense vegetation, or moist, shaded soil.
Cocoons are Spun in the Larval Environment
Once fully grown, flea larvae move to an undisturbed location to spin a cocoon. Within the larval environment, the cocoon becomes camouflaged with debris. Sometimes fleas pupate without cocoons. Naked pupae develop when there isn’t a nearby object or vertical surface to attach silk threads to.
Where Flea Cocoons Reside
Cocoons develop in same areas as eggs and larvae. Viable zones aren’t widespread around homes. To survive and reach adulthood, eggs must fall into warm, humid, protected microhabitats which contain plenty of larval food.
Most fleas develop indoors. 83% of immature fleas will be found within carpeting. Flea larvae move away from light. As a result, they live at the base of carpets. When forming a cocoon, their sticky silk gets bound in the carpet fibers. Within the carpeting, fleas cocoons are difficult to detect and are protected from insecticides. This is especially true for cocoons behind or underneath furniture.
Where cocoons are located in carpets depends upon the type of carpeting. In nylon loop and wool loop carpets, most cocoons reside at the base. In nylon saxony and nylon contract carpets, more cocoons are found near the canopy.
Flea cocoons are also often found indoors on animal bedding and upholstered furniture. Less common areas to find cocoon are hallways that get a lot of traffic, and wood and tile floors.
Immature fleas are less likely to be found outdoors. They’ll die in open, sun-exposed areas. Viable habitats must have high humidity, shade, and wind protection. Areas in yards where flea cocoons can be found include in dense vegetation, shaded soil, dog houses, crawl spaces, and under rocks. Flea larvae live on the soil’s surface or within the first couple centimeters. So the cocoons won’t be deeply buried.
Areas that get saturated can’t support development (e.g. near sprinklers). Flea larvae drown in water. Additionally, the water will dissolve and wash away the adult flea feces, which larvae require for food. Cocoons are more resistant to drowning, but larvae must survive to reach this stage.