Intraspecific variation in the reproductive capacity of Anopheles stephensi (Diptera: Culicidae).

Intraspecific variation in the reproductive capacity of Anopheles stephensi Liston females was studied under constant laboratory conditions. Of 421 engorged females examined individually throughout their lifetimes, 260 laid a total of 479 egg batches with a maximum of nine ovipositions per female. The number of eggs per oviposition varied from 5 to 247 (average 96.8). The number of ovipositions per female were correlated positively with the average number of eggs per batch and exhibited a negative binomial distribution among females, indicating that a small portion of the population exhibited a particularly high fecundity. Among the ovipositing females, the total fecundity and fertility ranged, respectively, from 5 to 1,084 eggs and from 0 to 1,036 larvae per female. The estimated maximal number of female progeny produced by a female in her lifetime was 317, and the estimates of net reproductive rate (Ro) and capacity for increase (rc) were 25.7 and 0.17, respectively. The number of eggs in the first oviposition was predictive of the total fecundity of a female. The wide range of individual variation in the reproductive capacity of An. stephensi emphasized the requirement for a large sample size for reliable estimation.