Figure 1. Experimental design showing the consecutive groups that the bees encountered in the various conditions.

QL triads consisted of one focal bee and two one-day-old foreign bees. Behavioural observations occurred between days 10 and 17. QL, queenless. ^aIsolation did not concern introduced bees in the infertile foreign condition or resident bees in all conditions. ^bQueen removal in the host colony was performed in the foreign QL condition only.