Posted: 19/07/2014 at 13:50
We have had solitary bee tubes up for a few years, spent hours watching them but never seen any caterpillars being brought in. I have only ever read that the bee grubs eat the pollen that is deposited by the parent bee. I have however, seen a few parasitic type wasps (and flies) that pop into a hole when mother bee is out collecting pollen, to deposit their own eggs. Could that have been a small wasp that was leaving some extra supplies for its offspring and then the mother bee kindly sealing the cell for it?