Mosquito host-seeking behavior is reproduced in the artificial environment. (A) Schematic view of a mosquito cage containing a recording device. (B) A typical pattern of selected host-seeking behavior of 60 female mosquitoes monitored for 48 h by the automated-device shown in (A). CO2 is delivered intermittently (2 sec every 15 min) during the 48 hours assay. Upper crossbar indicates light (yellow)-dark (gray) timer controlled conditions (6:00 ON; 22:00 OFF). (C-F) Patterns of selected host-seeking behavior (48 h) of females (C), males (D), blood-fed females (E), and females served with target Peltier covered with DEET (F). Note that only non blood-fed female mosquitoes show the selected host-seeking behavior. Mosquito behavior is represented as: host-seeking (blue), sugar-feeding (orange), and background behavior (magenta). (G) Both CO2 and heat are essential for activation of the selected host-seeking behavior (24 h). The behavioral assay was performed for 24 hours under each condition with CO2 only (light blue), heat only (light green), and CO2 + heat (blue), respectively. (H) CO2-activated simple locomotion activity of female mosquitoes (24 h). Note that female mosquitoes show higher locomotion activity induced by CO2 (dark orange) than by heat (light orange).