McInnes is keen for the young striker, who was the top scorer in the SPL Under-20 league last term, to gain some experience of regular first-team football.
Former Aberdeen captain Paul Hartley is the Wasps' manager, and he has brought McManus to Recreation Park until January.
Hartley said: “[McManus] is a very promising young player, and his goal scoring in the Under 20 league is remarkable where last season he was the highest scorer in that league.”
“He is a natural finisher and Aberdeen have high hopes for him and playing first team football will hopefully make him a more accomplished player and that would be a win-win for everyone.
“His opportunities at Aberdeen have been limited due to the form of Niall McGinn and there is no disgrace in that.”
McManus turns 19 tomorrow and he will hope to make a birthday debut in the Scottish League Cup tie against Peterhead at Balmoor Stadium.