Oviposition response of Aedes aegypti mosquitoes to different concentrations of hay infusion in Trinidad, West Indies.

Ovitraps containing various concentrations of hay infusion and tap water were exposed weekly in the field for 15 wk to determine the oviposition patterns of Aedes aegypti. The results showed 10, 20, 60 and 80% hay infusions each attracted similar numbers of Ae. aegypti eggs oviposited and egg occurrences. No repellent effect was observed. In another field study, significantly more eggs and egg occurrences were collected from 25 and 50% hay infusions and tap water. The differences in these results from those of a previous study in Puerto Rico are discussed.

Oviposition response of Aedes aegypti mosquitoes to different concentrations of hay infusion in Trinidad, West Indies

Ovitraps containing various concentrations of hay infusion and tap water were exposed weekly in the field for 15 wk to determine the oviposition patterns of Aedes aegypti. The results showed 10, 20, 60 and 80 percent hay infusions each attracted similar numbers of Ae. aegypti eggs oviposited and egg occurrences. No repellent effect was observed. In another field study, significantly more eggs and egg occurrences were collected from 25 and 50 percent hay infusions and tap water. The differences in these results from those of a previous study in Puerto Rico are discussed (AU)

Seasonal abundance, biting cycle, parity and vector potential of the mosquito Haemagogus equinus in Trinidad.

The mosquito Haemagogus equinus is a known vector of yellow fever (YF) in central America. Seasonal abundance, daily biting activity and the age composition of adult Hg.equinus female populations were monitored weekly during 1981-82 by human collectors on the ground at Point Gourde Forest, Chaguaramas, 16 km west of Port of Spain, Trinidad. 2. Landing collections of Hg.equinus showed diurnal activity from 06.00 to 20.00 hours (suntime), with a single peak between 08.00 and 14.00 hours. 3. Overall, 5.6% of Hg.equinus were collected during the dry season (December-April) and 94.4% during the wet season (May-November). 4. Mean density of Hg.equinus in relation to man ranged from 0.35/man-day in February to 133/man-day in July, with averages of 2.8 in the wet season, 36.9 in the dry season and 22/man-day for the whole year. 5. Monthly parous rates averaged 62.1% (range 0-88%); 2.8% of females were 2-pars, another 2.8% were 3-pars, but no older females of Hg.equinus were found (sample size 467). 6. These age-grading data indicate that Hg.equinus females have relatively short life expectancy and hence low vector potential, which may help to explain why YF virus has seldom been isolated from this vector species.