Fig. 6: OR42b^−/− animals showed constitutive Yorkie activation and enhanced body growth even in the absence of LP^WJL volatiles.

In all cases, germ-free embryos were treated either without (−) or with (+) inhalation of LP^WJL volatiles during entire larval stages. Larvae at 144 h AEL were used. a Btl expression (left) and relative tracheal coverage (right) in GF control and GF OR42b^−/− animals. The tracheal coverage of untreated GF control animals was taken arbitrarily as 1. The gut is arranged from anterior to posterior, moving from top to bottom in the photo. n = 3 biologically independent experiments. b Quantitative analysis of AstA⁺ EEC number per gut in GF control and GF OR42b^−/− animals (left) or GF OR42b-RNAi animals (right). n = 3 biologically independent experiments. c Body length in GF control and GF OR42b^−/− animals. n = 3 biologically independent experiments. Genetic rescue experiment by expressing OR42b in the OR42b knock-out animal. AstA⁺ EEC number per gut (d), and growth promotion of gut (e) and body (f) were measured. n = 3 biologically independent experiments in (d–f). Gut sizes of control GF animals were taken arbitrarily as 1 (g). n = 3 biologically independent experiments. Body length in GF control, GF OR42b^−/−, GF AstA^−/−, and GF OR42b^−/−; AstA^−/− animals. In each gut sample, an area (0.1 mm²) of a microscopic image from a similar gut region was randomly selected to count the number of AstA⁺ cells (b, d). Data are mean ± s.e.m. P values (*p < 0.05, **p < 0.01, ***p < 0.001, ns not significant) are indicated; one-way ANOVA with Tukey’s post hoc test in (d–f); two-way ANOVA with Tukey’s multiple comparison test in (a–c, g). Nuclei were stained with DAPI in blue. Scale bar, 50 μm. Genotypes, sample sizes, and statistical analyses are shown in Supplementary Data 1. Source data are provided in the Source Data file.