1. The urine of blood-fed mosquitos was collected and analyzed for elemental composition and osmolality. 2. Peak rates of urine flow averaged 4.9 droplets/min at 6 min following the beginning of the bloodmeal; peak flow urine contained, in mM, Na 178, K 4, and Cl 132, and the urine was approximately isosmotic to hemolymph. 3. As urine flow rates fell, the [Na] of the urine decreased and the [K] increased. Urine osmolality declined, measuring less than 100 mOsm/kg in some samples, as compared to 354 mOsm/kg measured in pre-bloodmeal hemolymph. 4. When urine flow rates had fallen to less than 10% of peak flow rates, urine again became approximately isosmotic to hemolymph, still containing Na and K as the principal cations. 5. Approximately 40% each of the water, Na and Cl contained in the plasma fraction of the bloodmeal was excreted during the 1-2h period following the bloodmeal. This excretion represents only 20-30% of the total loads ingested in the bloodmeal. 6. The data are consistent with dynamic changes in the functioning of both the Malpighian tubules and hindgut during the post-bloodmeal diuresis.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Animal Science and Zoology