LIFE TABLE STUDY OF AEDES-AEGYPTI (DIPTERA, CULICIDAE) IN PUERTO-RICOFED ONLY HUMAN BLOOD VERSUS BLOOD PLUS SUGAR

Life table studies were performed in 1996 with Aedes aegypti (L.) duri ng the low (cool/dry) and high (hot/rainy) dengue virus transmission s easons in Puerto Rico. Mated adult females from field-collected pupae were placed individually in cases and divided into 2 treatment groups: one was fed only human blood and the other human blood plus a 10% suc rose solution. Survival and number of eggs laid were recorded daily fb r each female. During both seasons, age specific survivorship was high er for the blood plus sugar group, groups fed only human blood had hig her reproductive outputs (m(x)), and net replacement rates (R-o) for b lood only groups were higher than for those fed blood plus sugar. Intr insic rates of growth (r) were the same for both treatments during the low (cool/dry) transmission season, but higher for the blood-only tre atment during the high (hot/rainy) transmission season. Our results in dicate that feeding on only human blood provides an evolutionary advan tage to Ae. aegypti females in Puerto Rico. These results are similar to those from an earlier study carried out with Ae, aegypti in Thailan d; the advantage of feeding on human blood does not seem to be restric ted to a particular geographic region. We also found that the benefits associated with human feeding persist through epidemiologically diffe rent times of the year. We conclude that feeding on human blood is rep roductively beneficial for Ae. aegypti, which map increase their conta ct with human hosts, and therefore may influence their vectorial capac ity for dengue viruses through frequent feeding on blood.