Location of and landing on a source of human body odour by female Culex quinquefasciatus in still and moving air

The orientation to and landing on a source of human odour by female Culex quinquefasciatus Say (Diptera: Culicidae) is observed in a wind tunnel without an airflow or with a laminar airflow of 0.2 m s−1. Odours from human feet are collected by ‘wearing’ clean glass beads inside a stocking and presenting beads in a Petri dish in a wind tunnel. Mosquitoes are activated by brief exposure to a 1 L min−1 jet of 4% CO2 positioned 10 cm from the release cage. In moving air at 0.2 m s−1, a mean ± SE of 3.45 ± 0.49 landings are observed in 10-min trials (five mosquitoes per trial), whereas 6.50 ± 0.96 landings are recorded in still air. Furthermore, 1.45 ± 0.31 mosquitoes are recorded on beads at any one time in moving air (a measure of individuals landing versus one landing multiple times) compared with 3.10 ± 0.31 in still air. Upwind flight to beads in moving air is demonstrated by angular headings of flight immediately before landing, whereas approaches to beads in still air are oriented randomly. The mean ± SE latency until first landing is 226.7 ± 17.98 s in moving air compared with 122.5 ± 24.18 in still air. Strategies used to locate a prospective host at close range in still air are considered.