Exercise 3 solution

(a) Worker. Both queen and worker larvae get royal jelly for the first three days; larvae switched to pollen and nectar after that grow into workers.
(b) Drone. Eggs laid in larger, drone-sized cells are left unfertilised and develop into drones.
(c) Queen. Larvae that keep receiving royal jelly, in a larger vertical queen cell, develop the full reproductive system of a queen.