Mosquito Flight Paths in Relation to the Environment. Influence of Blood Meals, Ovarian Stage and Parity2

Abstract

Suction traps were operated for 1 year in 2 adjacent habitats and the physiological constitution of the mosquito population was determined. Populations of Cs. melanura, C. nigripalpus, Ae. vexans, and An. crucians showed the largest proportion of females in egg stage I from February through June (except during May) with a roughly complementary distribution for females in stage II. Stage III females of all species had peaks in August, December, and June. These peaks were found to consist primarily of unfed females as only 10-15% of nulliparous and 1-2% of parous contained blood. Stage IV were rare and stage V showed little seasonal pattern. Within each egg stage, all 4 species had similar seasonal patterns. Blooded and gravid females were found to have similar behavior; although Cs. melanura and C. nigripalpus are woodland species, these females were proportionately more abundant in collections from the field, whereas in field species, viz., Ae. vexans and An. crucians, greater proportions occurred in the wooded swamp. Evidence is presented to show that the behavior of blooded females is dissimilar from unblooded females in the same egg stage and that females with enlarged abdomens (blooded and gravid) tend to have similar responses. In C. nigripalpus parous rates at dawn were 5% greater than in the evening. Parous rates did not differ between populations from the swamp and the field. Parous rates were lowest in stage I, higher in stage II, and highest in stage III females (stages IV and V were not examined). There was no relationship between the proportion in any 1 egg stage during the year and the percent of that stage parous. Thus, despite differences between species in flight behavior, host utilization, and breeding areas, the proportion of the population in any one stage of egg development, or the percent parous, or the percent of stage III females expressing partial autogeny, was highly synchronized during the year. The factors responsible for physiological synchrony between species were not determined.