Fig. 2

Darcin concentration influences individual volatile signature recognition. Levels of darcin were manipulated in male urine from three laboratory mouse strains to investigate the influence on volatile signature recognition. A ESI-MS of male urine from the three different strains (CD-1, known also as ICR; BALB/c; B6: C57BL/6 J). Dashed lines show the correspondence of mass peaks across all three strains. B SDS-PAGE confirmed different levels of darcin in the three strains. C, D Recognition of airborne odour within and between strains when r-darcin was added to match (c, e, h, j, l) or not match (d, k) the amount of darcin in the learned template. Buffer was added to all learned template and airborne test stimuli as a control. E Recognition of airborne odour when LMW and HMW urine fractions were mixed within or between strains and the amount of darcin in the HMW fraction matched (m, n, p, q, r) or did not match (o) that in the learned template. Data in C–E show the difference in time under the male test odour compared to female control (mean ± SEM). Recognition was assessed as more time near the male test stimulus than the female control, using matched pair t tests of untransformed ((a) t₁₁ = 2.56, p = 0.013; (e) t₁₉ = 3.25, p = 0.002; (m) t₁₁ = 4.48, p = 0.0005; (o) t₁₁ = 0.76, p = 0.23) or log transformed data ((c) t₁₁ = 2.53, p = 0.014; (d) t₁₁ = 0.38, p = 0.36; (f) t₁₂ = 4.86, p = 0.0002; (h) t₁₁ = 4.13, p = 0.0008; (i) t₁₉ = 1.10, p = 0.14; (k) t₁₁ = − 1.21, p = 0.87; (l) t₁₆ = 1.83, p = 0.043; (n) t₁₁ = 2.89, p = 0.007; (p) t₁₁ = 4.12, p = 0.0008; (q) t₁₁ = 6.88, p < 0.0001), or non-parametric Wilcoxon signed rank tests ((b) z = − 0.77, p = 0.75, n = 12; (g) z = 0.56, p = 0.30, n = 20; (j) z = 2.72, p = 0.002, n = 18; (r) z = 2.31, p = 0.009). *p < 0.05, **p < 0.01, ***p < 0.005, ****p < 0.001