Fig. 3: Molecular components of IR sensation.

a,d–f,h, Females in both zones were exposed to 5% CO₂ and human odour. Zone 1 was at ambient temperature (29.5 °C). Zone 2 was exposed to an IR source at 34 °C (a,d,f), all three forms of heat transfer at 34 °C (e) or an IR source only at the indicated temperature (h). a, The effect of CO₂ on navigation towards IR on the basis of the IHSI. The average IHSI in the +IR and −IR zones represents the overall trend in host seeking at a specific time during CO₂ exposure. b, Terminal flagellomere in an Aedes antenna. cs, coeloconic sensilla. Purported thermosensory neurons are shown in teal. c, The location of the dissection where the ends of the antennae were removed. d, IR-preference assays performed with dissected (diss.) and non-dissected (intact) wild-type (LVP) female mosquitos exposed to the presence or absence of IR. e, IR-preference assays performed with dissected and non-dissected LVP female mosquitos in the presence or absence of all three forms of heat transfer: IR, conductive (cond.) and convective (conv.) heat. f, Screen of mutant lines for impact on IR preference. LVP and Orlando (ORL) are the wild-type controls. g, qPCR analysis of all 10 Aedes opsin genes using RNA from female antennae. n = 3 biological replicates. Fold change in expression was calculated by normalizing to the lowest-abundance opsin, op12. h, The effects of the trpA1¹ and op1²,op2¹ mutations on IR preference across a range of Peltier temperatures. Data are mean ± s.e.m. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple-comparison test (f and h) and parametric two-tailed Student’s t-tests (d and e); *P < 0.05. For a, d–f and h, n = 6 biological replicates for each group. Exact P values are provided as source data.

Source Data