Bumble bee identification
In order to properly identify bumble bees, you need to first determine whether the bee you are examining is male or female. There are three different types of bumble bees you will encounter: workers, queens, and males. Both queens and workers are female. In most cases, queens and workers have similar coloration and physical features, except that queens tend to be much larger. Males can differ in coloration from females of the same species, as well as other physical characteristics.
All insects have three main body parts: the head, thorax and abdomen. Bumble bee keys will often refer to the coloration of the hairs on a particular abdominal segment, such as t2 (‘t’ refers to tergite, or the top of the segment). Note in the figure above that numbering of the abdominal segments always begins at the point where the abdomen meets the thorax.
Is your bumble bee male or female?
Males have thirteen antennal segments versus twelve antennal segments in females. Males of some species will have larger eyes, or longer hair than females of the same species. Males differ from females in having seven abdominal segments, whereas females have only six abdominal segments. Males do not have pollen baskets. A pollen basket is a broad concave shiny segment rimmed with long hairs that is found on the back legs of a female bumble bee. Pollen baskets are used to carry pollen back to the nest.
The USDA Forest Service along with The Pollinator Partnership has put together the following identification guides for eastern and western bumble bees. They can be downloaded below.
Eastern Guide by Sheila Colla, Leif Richardson and Paul Williams
Western Guide by Jonathan Koch, James Strange and Paul Williams