How much total RNA can be extracted from Drosophila brain
In my opinion you should try low input library prep protocols because in my experience even with a decent quantity of RNA, standardizing the sequencing is not an easy job. The manual says that this kit works with 10-20ng of RNA; always assume the higher limit to be true. There is a higher chance of loss (relative) during extraction also. Try doing precipitation with 5M LiCl and a little glycogen along with alcohol; but assuming your yield is 80ng you can still run replicates for statistical comparisons.