December, 2017

American Bumble Bee

Although diversity in the rest of the U.S. is higher, only one bumble bee species seems to live here in Austin, TX: the American bumble bee (Bombus pensylvanicus). While this insect is on the decline in many other areas, it is thriving around here and can be seen during all warm months.

The bumble bee is our only social native bee (honey bees originated in the Old World) and its nests are usually in the ground, often under bunch grasses. The queens hibernate through the brief winter and start their nests early in the spring. Once a queen has raised her first brood, they become the workers who will take over tasks such as gathering pollen, defending the nest and feeding the young. All workers are females, the offspring of the queen and a drone with whom she mated. As a nest's population increases, the queen eventually lays unfertilized eggs, which develop into the drones (males). These are larger than workers and so require more resources to successfully mature. The same is true for future queens, which are also produced late in the year. Towards the end of the season, the colony's queen exerts less influence over her workers and some of them might lay unfertilized eggs, thereby producing their own male offspring.