The influence of environmental factors and physiological stage on flight patterns of mosquitoes taken in the vehicle aspirator and truck, suction, bait and New Jersey light traps.

Abstract

Trap collections were made at 2 localities in Indian River County, Florida to determine the effect of illumination levels, wind velocity, temperature, humidity and characteristics of the trap site upon mosquito collectionsmade at regular intervals during the night. Collectionswere further examined to ascertain the proportion of each collection bloodfed, the egg stage constitution and parity level. All 9 species collected were crepuscular and were 2–4 times more active on nights the moon was shining. Unlike the other sampling methods, collections in the New Jersey light trap were larger in the morning twilight period than during the evening period. Collections were reduced to 1/3 by winds between 0.45–0.89 meters per second (mps) compared with <0.45 mps and to 1/2 by temperatures of 16°-18°C compared with 19°-21°C. Only Culex nigripalpus and Aedes vexans showed a response to higher humidity levels. Bait traps were more effectivein a host depauperate area and light traps were more effective beneath a forest canopy. Blood-fed mosquitoes were most abundant in vehicle-aspirator collections taken during daylight hours and in truck collections at dawn; attractant traps took very few. In all traps, the bulk of all mosquito populations was in egg stage II. While this stage comprised almost the entire contents of attractant-trap collections, the vehicle aspirator and truck trap took considerable numbers of advanced egg stages. Females in stages I, III, IV and V were most poorly represented in bait-trap collections. Gravid females of Aedes taeniorhynchus and Culex nigripalpus were highly crepuscular, flying at both twilight periods; gravid females of Psorophora conflnnis, Aedes sollicitans and Anopheles crucians flew primarily in the evening. Gravid females were even more responsive to moonlight than younger females. No effect of parity upon mosquito behavior was found.