Fig. 2.

Nine-exon HsOrs detect CHC extracts from different castes and HsOr263 detects a candidate queen pheromone component. a Representative action potential traces of three HsOrs to cuticular extracts of gamergates (left), workers (middle), and males (right). b Heat map of mean HsOr responses to each H. saltator extract. All extracts were applied at 1.2 µg of total hydrocarbon, and n = 3 for each extract-HsOr combination. c Responses to each of the 3 individual extracts for each caste for each HsOr tested. d Schematic of synthesis of 13,23-DiMeC37. (a) Ph₃P, acetonitrile, reflux; (b) NaHMDS, then 2-tetradecanone 3, CH₂Cl₂; (c) LiAlH₄, THF; (d) Ph₃P, CBr₄, CH₂Cl₂; (e) Ph₃P, 110 °C; (f) NaHMDS, then 2-hexadecanone, CH₂Cl₂; (g) 5% Pd/C, H₂, hexane. 13,23-DiMe37 is an ~equal mixture of the four stereoisomers. e Mean electrophysiological responses of the different HsOrs to 20 nmol of racemic 13,23-DiMeC37 (n = 6, error = s.e.m.). f A representative excitatory response to 13,23-DiMeC37 from an ab2 sensillum expressing HsOr263 and dose-dependent responses to different amounts of 13,23-DiMeC37 (n = 5). g Mean responses of HsOr263 to a panel of hydrocarbons found on H. saltator cuticle when expressed using Orco-GAL4 (w ⁺ , UAS-HsOr263; w ⁺ , Orco-GAL4, ab2A neuron, n = 6, top) or the empty neuron (Δhalo; w ⁺ , Or22a-GAL4/ w ⁺ , UAS-HsOr263, ab3A neuron, n = 5, bottom). All methyl-branched hydrocarbons used here and in subsequent experiments were racemic mixtures unless otherwise stated. (Error = SEM)