Notes on Breeding Fleas, with Reference to Humidity and Feeding

Experiments were carried out to show the different hygroscopic properties of certain foods supplied to flea larvae. These show that larvae of Ceratophyllus wickhami require about 15 to 28 per cent, of water in their food. Dried blood, albumen (blood) and material from the bottom of a squirrel's nest were used. Newly hatched flea larvae were fed on different substances at varying humidities and a constant temperature. A relative humidity of 80 per cent. gave the best results. Dried blood is a convenient food for breeding flea larvae in the laboratory, and may be used with or without a mixing medium, such as sand. Albumen is a more simple food on which a few larvae will survive, but at lower humdities than dried blood. Flea larvae will eat a great variety of other foods, including squirrel faeces, ground-up cockroach and dead adult fleas, but these do not provide a complete diet. It does not seem necessary for the larvae to have dried blood from the host of their parents, rabbit or human blood being quite as satisfactory.