As far as I know, I can plot either -log10(p-values) on the y-axis of a volcano plot, or the -log10(adjusted p-values) after adjusting them for example with Benjamini-Hochberg.

When plotting adjusted p-values, I can just set the cut-off to -log10(0.05) (see picture 1).

However when plotting the original p-values, I need to set a different cut-off. You can see in the raw data table that Species 9 already has an adjusted p-value >0.05 while Species 8 is the first one with adjusted p-value