Fig. 2: Integrating IR with other cues to direct host-seeking behaviour.
From: Thermal infrared directs host-seeking behaviour in Aedes aegypti mosquitoes
a, The effects of host-associated cues on host-seeking: 5% CO2, human odour and a 34 °C IR source. The HSI represents the average number of female mosquitos host seeking during 5 min experiment. b–d,f–h, Experiments in which both zones were exposed to CO2 and human odour, and one zone was exposed to IR at the indicated temperatures. Ambient temperature, 29.5 °C. b, The host-seeking frequency during an assay. c, There was no preference when both sides were at 29.5 °C. There was a strong preference for the 34 °C IR zone over the 29.5 °C zone. Obstructing IR from one of the two 34 °C IR sources produced a preference for the unobstructed source. Blocking IR from the 34 °C zone abolished the preference over the 29.5 °C zone. d, Removing the convective (conv.) barrier (−) did not increase the preference for the 34 °C zone. e, Female An. stephensi were exposed to two zones with human odour and 5% CO2. The zones were at 27 °C ambient temperature or exposed to 34 °C IR. f, IR thermographs under different ambient temperatures (left zone). The right zone was held at 34 °C. g, Assays performed under different ambient temperatures. Linear regression between the PI and temperature differences between the two zones. h, Assays were performed using different IR source temperatures (28–40 °C) in a 29.5 °C environment. i, The set-up for determining the distances at which Ae. aegypti detect 34 °C IR. Each side of the cage was exposed to human odour and CO2. IR was blocked on one side with an acrylic panel. Distances of 30–90 cm were used. j, The distances at which Aedes detect IR. Mosquitoes exposed to CO2, human odour and 34 °C IR in one zone, and 29.5 °C in the other zone. Data are mean ± s.e.m. Statistical analysis was performed using one-way analysis of variance (ANOVA) with Tukey’s multiple-comparison test (a, c, h and j) and parametric two-tailed Student’s t-tests (d,e); NS, not significant; ***P < 0.001. For a–e, g, h and j, n = 6 biological replicates for each group. Exact P values are provided as source data.
