Biting Rhythms of Selected Mosquito Species (Diptera: Culicidae) in Jahangirnagar University, Bangladesh

In Bangladesh, a number of important pathogens are transmitted by mosquitoes; however, at the present time, relatively little is known about the daily biting activity of most species of mosquitoes. Given that avoidance may be a viable option to decrease exposure to infected mosquitoes, we conducted a study to determine the biting patterns for mosquitoes during the 12 hour period from 18h00 to 06h00. Host-seeking mosquitoes which landed on the exposed legs and hands were collected using a mouth aspirator. Mosquitoes were continuously collected during the first 50 minutes of each hour and rested for the remaining 10 minutes. The hourly catches of mosquitoes were kept in labeled cups according to the hour of collection. A total of 711 mosquitoes from three genera and seven species were collected. Four species belonged to Culex , two to Mansonia and one to Armigeres . Among the collected species, six were recognized as vectors of pathogens in Bangladesh including the vectors of filariasis [ Culex quinquefasciatus (56.54%), Mansonia uniformis (15.75%), Mn. annulifera (12.38%), and Armigeres subalbatus (4.64%)] and Japanese encephalitis [ Cx. tritaeniorhynchus (7.17%), and Cx. vishnui (1.55%)]. One non-vector species of mosquito, Cx. hutchinsoni (1.97%), was also collected during the study. In general, biting commenced just after sunset, increased gradually, peaked between 24h00 and 01h00 and decreased to the lowest level between 05h00 and 06h00. The biting densities of mosquitoes ranged from 9.1 mosquitoes per men hour (mph) in July to 16.5 mph in May, with an overall average of 11.85 mph. The highest and lowest biting density was found in May and July respectively. Biting activity of various vector species differed during different hours in the night. Use of personal protection methods should be encouraged during the peak biting times to minimize vector-host contact.