Bald-faced hornet to laying eggs while the workers take over all other necessary housekeeping tasks. At some point, sometime before the midpoint of colony life, the colony will begin to invest energy in producing reproductives as well. This marks the transition into the reproductive stage. There is an extensive time period where both workers and reproductives are raised. Production of both castes limits the size of the work force. However, an early switching time is highly adaptive for social wasp colonies in limiting the risk of total loss. In a sampling of 50 colonies taken in Maryland in 1977, workers were produced
Bald-faced hornet fertilized at the end of the previous season begin new colonies. A queen selects a location for its nest, begins building it, lays a first batch of eggs and feeds this first group of larvae. These become workers and assume the chore of expanding the nest. They chew up wood, which mixes with a starch in their saliva. They then spread it around with their mandibles and legs, and it dries into a papery structure. The workers guard the nest and feed on nectar, tree sap and fruit pulp (particularly that of apples). They also prey on insects and other