Mosquito Flight Paths in Relation to the Environment. Effect of Vertical and Horizontal Visual Barriers

Abstract

The non-migratory flight behavior of An. crucians, An. quadrimaculatus, Ae. vexans, Coq. perturbans, C. nigripalpus, Cs. melanura, P. confinnis, and other species was studied in Central Florida. Frame and webbing barriers were placed on opposite sides of suction traps to simulate a trap located in a hedge. While appearing solid, open spaces between the strands of webbing permitted mosquito flight. Suction trap collections were also made beneath a 30 ft × 30 ft horizontal net of webbing that reduced light intensities by 80%. In a field location, nearly all species were taken in 2-3X greater numbers in traps equipped with vertical barriers than in traps without barriers. When the experiment was repeated in a wooded swamp possessing an understory of shrubs and ferns, traps with barriers failed to take larger numbers of any species except Cs. melanura. Raising the height of the vertical barriers on traps located in the field by 1 ft reduced their effectiveness. All species, Cs. melanura and C. salinarius excepted, were taken in reduced numbers in traps beneath the horizontal nets. During full moon periods, the response of mosquitoes to all barriers was reduced. The differing levels of response to the experimental conditions by various species are interpreted in relation to their normal flight habitats, visual perception, light intensities, and probable mode of response.