The Relative Attractiveness of Carbon Dioxide to Parous and Nulliparous Mosquitoes1

Standard New Jersey light traps were compared with and without a dry-ice supplement in a coastal area of New Jersey. The tests were conducted to determine the relative attractiveness of CO2 to parous and nulliparous specimens and to determine if the addition of CO2 as an attractant affected the age composition of the mosquitoes in the sample. More than 15,000 female mosquitoes were collected during the study; Culex salinarius, Aedes canadensis, Ae. cantator, Ae. sollicitans and Ae. vexans were the predominant species. Ovarian dissections revealed that a significantly greater percentage of parous mosquitoes was collected in the trap where light was the only attractant. The addition of CO2 consistently attracted a greater proportion of the nulliparous specimens. The light trap baited with dry ice, however, caught more than 17 times the number of mosquitoes and increased the incidence of the major species by 8- to 45-fold. Data suggested that the addition of CO2 in the form of dry ice attracted a greater percentage of nulliparous mosquitoes but increased the total catch sufficiently to warrant its continued use for arbovirus sampling in most situations.