Host-feeding patterns of Culex tritaeniorhynchus and Anopheles sinensis (Diptera : Culicidae) in a ricefield agroecosystem

Abstract

Adults of rice-field mosquitoes were collected between May and September of 1996 and 1997 in Nishi Arita, Saga Prefecture, Japan, to determine their feeding pattern in an area where animals were available in large numbers. In total, 31,804 female Culex tritaeniorhynchus and Anopheles sinensis were collected from animal sheds using dry ice-baited light traps and mouth aspiration. Light traps in all the animal sheds captured large numbers of mosquitoes (cowsheds 7,933,pigsties 6,441 and chicken sheds 5,267 mosquitoes), although few fed upon the chickens. Overall, 62% (N=7,113) of fed Cx. triaeniorhynchus and 74% (N=7,261) of An. sinensis were caught by light traps at the cowsheds and pigsties compared to less than 5% (N=5,267) at the chickens sheds. The type of animal in the shed was the most important factor determining the feeding rates. Blood-meal identification by direct ELISA indicated that both Cx. tritaeniorhynchus and An. sinensis preferred cows and pigs to chickens. Over 90% (N=143) of the fed mosquitoes collected from one chicken shed had fed upon cows in an adjoining cowshed. The tendency to feed upon cows and pigs more than on chickens was observed both in the hillside (terraced) and lowland ricefields. This trend is shown in the results obtained by both the aspirator and light trap collection methods.