A study of nitrogen and uric acid patterns in the excreta and body tissues of adult Aedes aegypti

Abstract

The studies reported in this paper have been undertaken to establish eventually, if possible, metabolic changes in the physiological pattern of the mosquito Aedes aegypti, which may be related to demonstrated changes in its susceptibility or resistance to infection produced by various biological, biochemical, or physical factors. Preliminary studies of nitrogen metabolism in this animal have shown that immediately after emergence as adults. A. aegypti excrete considerable amounts of nitrogenous material, the bulk of which has been identified by chemical, physical, and enzymatic methods as uric acid. Since the output of uric acid decreases rapidly thereafter, and remains at extremely low levels during the remainder of the adult existence of the mosquitoes, so long as they are maintained on sucrose alone, these data suggest that immediately following emergence mosquitoes are excreting essentially the products of pupal metamorphosis rather than the products of adult metabolism. The data also indicate that ingested proteins are utilized by the mosquito, only if they are converted to and excreted as uric acid, since there is an immediate and extreme rise in the proportional output of uric acid following a blood meal, whereas in mosquitoes maintained on plasma or lysed red cells only a very small proportion of the excreted nitrogen is uric acid. This assumption is supported by the comparative tissue nitrogen levels of mosquitoes maintained on these diets. Finally, the data suggest that all the proteins necessary for adult existence are obtained by the female adult mosquito during its larval developmental period, and in the absence of any egglaying activity it is capable of conserving its nitrogen resources and maintaining itself adequately at a minimal level of protein katabolism.