Blood-digestion kinetics of four Anopheles species from Trinidad, West Indies.

The blood-digestion kinetics of Anopheles albitarsis, An. aquasalis, An. bellator and An. homunculus were determined in the laboratory using females collected from two field sites in Trinidad. Anopheles aquasalis displayed the highest rate of haemolysis (giving an absorbance of 0.36 at 410 nm), followed by An. albitarsis (0.16), An. bellator (0.07) and An. homunculus (0.05). Trypsin activity peaked 12-24 h after blood feeding and then declined to zero at 60 h in all four species. Anopheles albitarsis had significantly higher maximum trypsin activity (0.69 units) than An. aquasalis (0.28), An. bellator (0.18) or An. homunculus (0.12) (P < 0.01). Aminopeptidase activity patterns were similar for An. aquasalis, An. bellator and An. homunculus, with peak activity at 18 h. Among the An. albitarsis mosquitoes, peak aminopeptidase activity occurred at 24 h. The peritrophic membrane developed 18, 30, 30 and 36 h post-feeding in An. aquasalis, An. albitarsis, An. bellator and An. homunculus, respectively. Stage V ovarian follicles began to mature 36 h after An. albitarsis and An. bellator fed to repletion and after 48 h in An. aquasalis and An. homunculus. Ovarian development in the four species was not affected by patterns of erythrocyte haemolysis, proteolytic enzyme activity or peritrophic-membrane development. The inter- and intra-specific variations observed in the blood-processing physiology of the four species of Anopheles are briefly discussed in terms of phylogeny.