Arnaldo Maciá

SEASONALITY AND ABUNDANCE OF THE MOSQUITO ISOSTOMYIA PARANENSIS FROM PHYTOTELMATA IN TEMPERATE ARGENTINA

ABSTRACT Sampling was conducted for 1 year in a marsh near Buenos Aires from axils of Scirpus giganteus, a larval habitat of the poorly known sabethine mosquito, Isostomyia paranensis. Immatures of this species were recovered on every sampling date, averaging 3–4/plant in April and decreasing to 0–1/plant in October–December. The spatial distribution of Is. paranensis immatures was clumped, and larval age skewed toward 1st instars. The percentage of mosquito-positive S. giganteus was negatively correlated with accumulated rainfall 1 wk before collection. Microcrustacea were the only other invertebrates common in this phytotelmata, and no parasites or pathogens were detected in Is. paranensis. Fourth instars of this species attacked and killed one another in the laboratory, but only algae were recovered from dissected digestive tracts of field-collected larvae. Adult females of this species emerged from independent collections of pupae refused blood, but females captured at human bait readily consumed human blood. Mean (±SD) number of eggs developed by females collected at human bait and fed with blood (77.4 ± 22.8) was not significantly different from the mean number of eggs developed by females collected as pupae and fed on sugar (72.0 ± 23.0).