Fig. 4. Cuticular chemical profile of E. muscae sporulating houseflies.
a Tentatively identified compounds in cuticular hexane extracts of early (3–8 h post death) and late (25–30 h post death) female and male sporulating cadavers and conidia. Numbers in table denote fold change in intensity of total ion chromatogram (TIC) compared to corresponding uninfected controls, so early treatments are compared to early controls and late treatments are compared to late controls. The symbol + denotes presence in the sample, but not in corresponding control (+: <5.5 × 107, ++: 5.51 × 10 < 5.5 × 108, +++: 5.51 × 108 < 5.5 × 109, ++++ >5.51 × 109 Total Ion Chromatogram (TIC)), and − denotes absence, i.e. only found in uninfected control samples and shown as fold change between early and late in two right-most columns. Compounds highlighted in blue have previously been identified to stimulate male sexual behaviour in houseflies. For each compound the retention index (KI, DB-1 column) is given (n = 5 per treatment, except n = 2 for female +Em conidia). b Principal component analysis (PCA) of cuticular and conidia extracts (hexane) shown in (a). Sample groups are colour-coded according to treatment and the outer-most samples connected by a solid line and background shown with shaded colour to show variation between replicate samples.