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Studies on the Effect of Frequency of Feeding upon the Biology of a Rabbit-Adapted Strain of Pediculus humanus

1963; American Society of Parasitologists; Volume: 49; Issue: 3 Linguagem: Inglês

10.2307/3275828

1937-2345

R. H. Gooding,

Study of Mite Species

When a rabbit-adapted strain of Pediculus humanus was maintained at 30 C and 75% relative humidity between feedings, the rate of growth of the nymphs and the fertility, fecundity, and longevity of the adults were affected by the frequency of feeding. Nymphs fed less frequently than once every 48 hr did not live to undergo the first molt. Within the range 8 to 48 hr between feedings, lice molted at an earlier age and took more meals when fed at shorter intervals. The relationship between the number of feedings before molting or during the preoviposition period (f) and the interval between feedings (t) was found to be: f = k/(log t) where k and a are constants. An optimum frequency of was predicted from the above expression, but nymphs fed about twice as frequently as the predicted optimum developed at the same rate as those fed near the predicted optimum. Within the range tested (i.e., 12 to 120 hr between feedings), adult lice that were fed frequently lived longer and laid more eggs (of which a greater percentage hatched) than lice fed infrequently. The relationship between the length of time required to produce an egg and the interval between feedings was found to be a straight line. It was predicted that under conditions of unlimited access to food the maximum oviposition rate for this strain would be 17.6 eggs/female/day. Early attempts to rear Pediculus humanus on hosts other than man have been reviewed by Culpepper (1948) and by Davis and Hansens (1945). Most of these attempts, as well as attempts by Culpepper (1948) to rear P. humanus on goats, dogs, and calves, were unsuccessful. The human body louse has been reared successfully on rabbits (Davis and Hansens, 1945; Culpepper, 1946, 1948). Since Warburton (1910) described the life history of the human body louse, much has been published on the growth, fertility, fecundity, and longevity of Pediculus humanus. The growth rates of nymphs, reared under various conditions on man, have been published by Warburton (1910), Nuttall (1917b), Bacot (1917), Hutchinson (1918), Buxton (1940), and Busvine (1948). Similarly, data on the biology of the adults have been published by Received for publication 11 June 1962. * This work was supported in part by U. S. Public Health Service Grant E-1384. t Present address: Department of Pathobiology, Johns Hopkins School of Hygiene and Public Health, 615 North Wolfe Street, Baltimore, Maryland. Bacot (1917), Nuttall (1917b), Haddow (1941), and Busvine (1948). As early as 1917, sufficient data had been accumulated to allow Nuttall (1917b) to conclude that the rate of growth and the number of eggs laid depended upon the food supply and the temperature at which the lice were maintained. Buxton (1947) noted that it is easy to show that lice lay more eggs, and that the larvae grow more rapidly, if they are held against the skin continuously rather than at intervals, but it is not known whether this is an effect of temperature or of frequent feeding (p. 36-37). Busvine (1948) published data which confirmed this statement for both head and body lice. Although considerable work has been done to demonstrate a relationship between food supply and the biology of Pediculus humanus, the question raised by Buxton's (1947) statement (cited above) has not been answered, nor has the relationship between food supply and louse biology been quantitated. This investigation was undertaken with a view to filling these gaps in our knowledge of louse biology.