Ecological studies on overwintering populations of Culex pipiens pallens : 3. Movement of the mosquitoes in a cave during overwintering

Abstract

An ecological study was carried out on distribution, movement and change in the body weight of Culex pipiens pallens Coquillett during their overwintering. Overwintering population of Cx. p. pallens was distributed aggregatively in a cave (air-raid shelter). More mosquitoes were found in the inner room of a 3-room shelter and gathered on the lower part of the wall. The degree of such aggregations changed with fluctuation in the temperature and humidity inside the room, and became maximum in January. The movement of mosquitoes was influenced by air temperature : It was least frequent in February when the temperature was lowest. The movement was least frequent on the lower part of the wall. The mobility rate (percentage of mosquitoes which changed their resting positions) was about 70% on average. Mean body-weight of mosquitoes before and after overwintering was 1.271mg and 0.708mg, the reduction rate being 44.3%.