Cat flea biology

A female cat flea can begin laying eggs when it has mated and have been an adult flea for a few days. Usually, a cat flea lives for about a month and can lay about 200 eggs. The eggs are laid in dog or cat fur. They fall off the host, wherever it is. On a dark background, the eggs look like spilled sugar. The hatching time of the eggs is 2-3 days at room temperature. The larvae then crawl into cracks in the floor or in the carpet, where they feed on organic material as well as bloody excrements from the adult fleas. During this period, which lasts a few weeks, they cannot tolerate low humidity. A relative humidity of less than 45% will kill them. This is one of the reasons why flea problems are not as common during the heating season.

At the end of the last larval stage, the larva spins a cocoon around itself. At the beginning, the cocoon is sticky. It is camouflaged by sand and dust, and is virtually impossible to vacuum up off a carpet. The larvae often stay in the cocoon for about a week. The adult flea now decides when to emerge from the cocoon. If the air is too dry, too cold, or if there is no host animal in the vicinity, the flea might stay inside the cocoon for months.