Results
First, we examined the expression of each separate SFP gene, and detected that the expression of LyAcp8b significantly increased 48h after mating (Fig. 1, Table 1). We also found that LyAcp5 andLyAcp8a expression altered significantly after mating, although post-hoc testing did not show any significant difference between specific time points (Fig. 1, Table 1). For LyAcp5 , this seems due to the difference in expression between 48 h and 196 h, and forLyAcp8a (very similar to LyAcp8b) expression increased 48 h after mating. Two samples showed consistently high expression inLyAcp5 , LyAcp8a and LyAcp8b (#92, #110), but not in the other genes and we could not find any technical or biological features explaining this pattern (e.g., RNA extraction date, body size). In LyAcp8a and LyAcp8b , we detected significant differences between experimental blocks, but not interaction with Hours after mating. In contrast, the three remaining SFP genes did not show any significant change in expression level throughout our monitoring, suggesting that the production of these SFPs did not increase after mating (Fig. 1, Table 1). We also like to note that the expression at 196 h after mating is not always low, compared to 3 h after mating (Fig. 1), while by that time the prostate gland is expected to be fully replenished.
Next, we inspected the overall change in expression across all SFP genes. To do so, we conducted a PCA to create representative variables for overall SFP gene expression. PC1 explained 50.0% of the total variance, and this variable seems to correspond with Hours after mating, although this is not the case after FDR correction (Fig. S2, Table 2, Table S2). In contrast, PC2 explained 26.5% of the total variance, and seemingly explained the difference between SFP genes, again after FDR correction statistical significance disappeared (Fig. S2, Table 2, S2). The important, additional insight from PCA is that the expression of SFP genes after mating differed between separate SFP genes, which is visualized by the directions of PC loadings (Fig. 2, Table 2).