Distribution of biting Culex tritaeniorhynchus (Diptera: Culicidae) among pigs: effects of host size and behavior

The distribution of biting Culex tritaeniorhynchus Giles females among pigs was analyzed to determine the effect of host size and behavior on host selection by the mosquitoes. The number of Cx. tritaeniorhynchus collected per sow was significantly greater than that on her piglets. Sleeping piglets were attacked more frequently by mosquitoes than wakeful ones. The distribution of biting mosquitoes among different-sized piglets was aggregated compared with expected random distribution, and one of four data sets showed significant host size-dependence. Pig activity (including mosquito defensive behavior) significantly reduced the number of attacking mosquitoes, but total pig activity score was not related significantly to total mosquito counts during the early half of the night or the entire night. Data on the residence times of mosquitoes on pigs indicated that interrupted (and consequently multiple feedings) were frequent. The effects of size-dependent (age-dependent) host selection by Cx. tritaeniorhynchus on the amplification of Japanese encephalitis virus were discussed in relation to control programs.