colour of scale_alpha_continuous

[MjelleLab]

trafficstars

Is it possible to add a colour to scale_alpha_continuous so that it is the same as the colour of my fills. I have two rings in the tree with colour c("#081d58", "#67000d") and would like to add two scale_alpha_continuous for each of the fills in the two rings.

scale_fill_manual(
    values=c("#081d58", "#67000d"),
    guide=guide_legend(keywidth=0.5, keyheight=0.1, order=4,title = "Sample type")
  ) +
  scale_alpha_continuous(
    range=c(0, 1), 
    guide=guide_legend(keywidth=0.5, keyheight=0.3, order=5,title = "Abundance")
  )