| Yellow-faced Bumblebee | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Apidae |
| Genus: | Bombus |
| Subgenus: | Pyrobombus |
| Species: | B. vosnesenskii |
| Binomial name | |
| Bombus vosnesenskii Radoszkowski, 1862 |
|
The Yellow-faced Bumblebee (Bombus vosnesenskii) is distributed through western North America. This species grows to 1–2 centimetres (0.4–0.8 in) long, with queen being larger than the workers.[1] B. vosnesenskii is characterized by the yellow coloration of the head pile, the mostly black thorax and abdomen, a single yellow thoracic stripe on the lower abdomen, and blackish wings.[2]
The overwintering queen first appears during spring and establishes underground colonies. After laying her first brood she, and the workers, will incubate the cluster until the adults emerge. The queen and workers use thermoregulation to incubate the cluster. The fuel for the bumblebee's thermoregulation during incubation is derived from honey (when the bumblebee is not foraging), nectar, and pollen.[3] Late in the season males and young queens leave the nest and mate. While old males, queens, and workers die. The new queens overwinter and the cycle continues.[1]
B. vosnesenskii', like most bumblebees, use thermoregulation to maintain a stable body temperature several degrees above the ambient temperature. At rest, bumblebees have temperatures close to ambient temperature. To generate power for flight, bumblebees need to raise the temperature of the flight muscles to above 30 °C (86 °F).[4] The route of heat exchanged in B. vosnesenskii is regulated by the heat transfer from the thorax to the abdomen by the variations of hemolymph flow in the petiole, the narrow region between the abdomen and thorax. At low ambient temperature, the hemolymph flows from the thorax and abdomen simultaneously. As a result, the counter-current exchange of heat in the petiole retains most of the energy in the thorax. When ambient temperature is high, the flow between the thorax and abdomen alternate. The amount of counter-current heat exchange in the petiole is reduced and allows hemolymph to transfer large amounts of heat from the thorax to the abdomen.[5]