On the life history and the biology of the rat-flea, Nosopsyllus fasciatus (Bosc.)

Abstract

A brief summary of previous work done on the life history and the biology of fleas is given. The duration of various well-defined periods during the course of metamorphosis of the flea at temperature 23° C. and 90 per cent relative humidity is recorded.It is experimentally proved that blood, although the most important part of the nutritional requirements of the flea larvae, is by itself not sufficient for their normal and successful development. The flea larvae require an additional food which in nature is supplied by the organic refuse present in the bed of the host of the adult fleas.Experiments were carried out to determine the nutritional value of different constituents of the blood and it was found that the fibrin has no nutritive value to the flea larvae, while the serum and red corpuscles have equal nutritive value. Lagging larvae are the result of some deficiency in the food. The serum possesses all the essential proteins for the normal development of flea larvae but lack of the required amount of iron in it increases the percentage of mortality and delays the development. On the other hand the red corpuscles or haemoglobin, though rich in proteins containing iron but on account of the poverty of some other proteins necessary for the normal development prolong the development and increase the percentage of mortality. It was further experimentally proved that flea larvae require blood for their development in order to obtain the necessary supply of iron for their normal growth. The denatured proteins of the blood and its constituents have no nutritive value for the flea larvae.