Segregation of CO
and heat-sensing behavior mediated by mosquito proboscis. (A-D) Effect of appendage-ablations on the selected host-seeking behavior (left column) and CO2-activated locomotion (right column). Behaviors of each group of 60 female mosquitoes lacking antenna (A), maxillary palps (B), proboscis (C), or leg (D) were monitored for 24 h by the automated-device. CO2 was delivered intermittently (2 sec every 15 min) during the 24 hours assay. Each graph shows selected host-seeking (blue), sugar-feeding (orange), background (magenta), and CO2-activated locomotion behavior (dark orange). (E) Total activity counts of selected host-seeking behavior during the 24 hours assay. Note that antenna-, maxillary palps-, and proboscis-less mosquitoes show significantly-reduced activity compared to the leg-less mosquitoes (**p < 0.01 and *p < 0.05, t-test; mean ± SD, n = 5). (F) Total activity counts of CO2-activated locomotion during the 24 hours assay. Note that antenna- and maxillary palps-less, but not proboscis-less mosquitoes show significantly-reduced locomotion compared to the intact mosquitoes without CO2 (***p < 0.005, **p < 0.01 and *p < 0.05, t-test; mean ± SD, n = 5).