Fecundity of Ochlerotatus albifasciatus (Diptera: Culicidae) from Córdoba, Argentina

Abstract

Seasonal differences in the number and length of gonotrophic cycles of Ochlerotatus albifasciatus were determined in a temperate area of Argentina, in addition to analysis on number of eggs laid by females corresponding to the number of bloodfeedings per gonotrophic cycle throughout the year. Landing females were collected by using human bait and mechanical aspirators along the southwestern coast of Mar Chiquita Lake (in northeastern Córdoba Province) from February to November 2000. Collected females were kept in captivity under natural weather conditions, fed on a sugar solution (10%), and provided blood via a human host by different methods (treatment A: 1 bloodfeeding/gonotrophic cycle and treatment B: 2 or 3 bloodfeedings/gonotrophic cycle). A maximum of 5 gonotrophic cycles (average 2.24 +/- 1.11) were determined by dissecting ovarioles. The gonotrophic cycles were longer in females of treatment B (11.23 +/- 4.06 days) than those of treatment A (9.02 +/- 5 days). Females that completed the highest number of cycles were collected in winter and during the beginning of spring. The average number of eggs laid in each cycle was 90 (SD = 37.85) for treatment B females and 80 (SD = 29.99) for those of treatment A, with significant differences between treatments. Considering both treatments, the number of eggs laid was significantly higher after 3 blood meals than with 1 or 2 feedings. These results suggest that an increase in the number of feedings would lengthen the cycle and increase the production of eggs. No correlation was found relating to temperature and the length of the cycles, which suggests that the number of blood meals may be the determining factor in seasonal variations in egg production.