Margot Childerstone, of Dunedin, asks :-
Bee-like insects were hovering at a corner of my house, behind the lemon tree, apparently wanting to get in under the weatherboards. They were there three days then vanished. There were lots of similar looking insects on the Senecio Greii a few days later. What was going on?
Barry Donovan, an entomologist with Plant and Food Ltd, responded.
The insects shown are honey bees. The fact that they were trying to get into the weatherboards indicates they were scout bees which were looking for a place for a swarm to move into to establish a new colony. Because other scouts may appear, the area should be sprayed with a residual insecticide, otherwise if there is a hole into the wall a swarm could move in. There should be a thorough search along the whole wall for access points for bees, and any discovered should be blocked at once with a substantial sealant.
If bees were to become established the colony could exist for many years. Usually there are no problems, but sometimes honey can ooze from honeycombs, causing damage to inside wall coverings. Also, if people cross the bees flight path, stings may be inflicted.
Other insects that could be mistaken for honey bees that can inhabit cavities in buildings are wasps and bumble bees. A Wasp nest is initiated by a queen wasp in spring, who builds the start to a wasp nest all by herself and raises 40 - 60- worker wasps. The workers soon take over all nest construction and brood-tending duties while the queen lays more and more eggs as the colony grows. By mid-late summer there will be a constanst stream of wasps entering and leaving the building, and at this time many hundreds of male or drone wasps begin to appear, followed soon after by hundreds of new queens. The males and new queens leave the nest and mate in the vicinity, and as autumn fades into winter the nest dies and only the new queens survive until spring, hibernating in protected sites such as under dead, peeling bark on branches.
The life cycle of bumble bees is very similar to that of wasps, and sometimes nests can be built in the walls and roof cavities of houses, but more commonly under the floors. As with honey bees the secret to keeping these insects out of dwellings is to block all possible access holes.