The Influence of Seasonal Sex Ratio on the Number of Annual Generations of Aedes triseriatus1,2

Abstract

The sex ratio of emerging Aedes triseriatus (Say) strongly favored males during the early part of the season. This factor is partly responsible for delaying the beginning of oviposition until late June, leaving open a narrow time gate for development of a partial 2nd generation before onset of egg diapause in late July. Comparison of emergence patterns from treeholes alternately open to current season's oviposition with those closed to current oviposition indicated that ca. 15–28% of adults emerging from the former represented a partial 2nd generation, this yielding an estimate of 1.2–1.4 adult generations during 1977 and an estimate closer to 1.2 for years when May temperatures and July rainfall are more normal than they were in 1977. Of 12 treeholes monitored over a 2-yr period 3 accounted for 58% of the adult A. triseriatus produced.