Increased fecundity of Aedes aegypti fed human blood before release in a mark-recapture study in Puerto Rico

Laboratory experiments suggest that utilization of blood rather than natura l sugar sources for energetic needs affords female Aedes aegypti a reproduc tive advantage over conspecifics that use sugar To test this hypothesis und er field conditions, we carried out a mark-release-recapture study in Flori da, PR. Adult females (F-1) reared from field-collected eggs were provided with a diet of human blood alone or human blood plus a 20% honey solution b efore their release. Backpack aspirators were used to collect mosquitoes fr om release houses for 5 consecutive days beginning the 2nd day after releas e. Survival was estimated from the slope of the regression line of the log- transformed daily number of recaptures for each treatment group. To compare fecundity of the treatment groups, each recaptured female was dissected, o varies were removed, oocytes counted, and Christophers' stages of oocyte de velopment scored. Recapture rates were 30% for the blood-only group and 23% for blood plus honey group. The daily survival rate of the blood-only grou p (55%) was not statistically different from that of the blood plus honey g roup (69%) (t = 0.32, P > 0.05). By analysis of variance, fecundity (averag e number of stage m-V oocytes) was significantly higher in the females fed human blood alone (n = 103, 109 oocytes/female) than in the group fed on bl ood and honey (n = 50, 95 oocytes/female) (P = 0.0007). The observed gonotr ophic cycle length of the recaptured females ranged from 3 to 7 days. Resul ts from our field study are consistent with laboratory life-table experimen ts that suggest feeding exclusively on human blood provides a reproductive advantage fur female A. aegypti.