Bombus ternarius | |
---|---|
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Hymenoptera |
Family: | Apidae |
Subfamily: | Apinae |
Genus: | Bombus |
Subgenus: | Pyrobombus |
Species: | B. ternarius |
Binomial name | |
Bombus ternarius Say, 1837 |
Bombus ternarius, commonly known as the orange-belted bumblebee or tricoloured bumblebee, is a yellow, orange and black bumblebee. It is a ground-nesting social insect whose colony cycle lasts only one season, common throughout the northeastern United States and parts of Canada. The orange-belted bumblebee forages on Rubus, goldenrods, Vaccinium, and milkweeds found throughout the colony's range. Like many other members of the genus, Bombus ternarius exhibits complex social structure with a reproductive queen caste and a multitude of sister workers with labor such as foraging, nursing, and nest maintenance divided among the subordinates.
B. ternarius is a small, fairly slender bumblebee. The queen is 17–19 mm (0.67–0.75 in) long and the breadth of the abdomen is 8.5–9 mm (0.33–0.35 in). The workers are 8–13 mm (0.31–0.51 in), and the drones are 9.5–13 mm (0.37–0.51 in) in length. Both the worker and the drone have abdomens about 4.5–5.5 mm (0.18–0.22 in) in breadth.
The queen and workers have black heads, with a few pale yellow hairs. The anterior and posterior thorax and the first and fourth abdominal segments are yellow, abdominal segments 2 to 3 are orange, and the terminal segments are black. The queen and the workers are close in resemblance, and the most striking difference between them is in the size of their fat deposits. Workers have very little fat, particularly in their abdomen, leaving plenty of room for the honey stomach, an enlargement of the oesophagus in which nectar can be stored on foraging trips. In contrast, in young queens, the abdomen is largely full of fat. This leads to queens being heavier for their size than workers.
The drone has a yellow head with a few black hairs. The coloration of the thorax and abdomen is similar to that of the females, with the exception that the last abdominal segments are yellow on the sides. The fur of the drone is longer than that of the females.
B. huntii, another species of bumblebee common throughout the western United States, is nearly identical in coloration to B. ternarius, though it has primarily yellow facial hairs rather than black.