ese colors can range from entirely black, to bright yellow, red, orange, white, and pink. Thick pile can also act as insulation to keep the bee warm in cold weather. Further, when flying a bee builds up an electrostatic charge, and as flowers are usually well grounded, pollen is attracted to the bee's pile when it lands. When a pollen covered bee enters a flower, the charged pollen is preferentially attracted to the stigma (female part of plant-thus fertilization occurs) because it is better grounded than the other parts of the flower.
Brightly Colored Bumble Bee. Image Courtesy Christian Sand.
Bumblebees are typically found in higher latitudes and or high altitudes; though exceptions exist (there are a few lowland tropical species). A few species range into very cold climates where other bees might not be found; Bombus. polaris can be found in northern Ellesmere Island (west of Greenland)—the northern most occurrence of any true social insect. One reason for this is that bumblebees can regulate their body temperature, via solar radiation, internal mechanisms of "shivering" and cooling from the abdomen (called heterothermy).
Bumblebee colonies are usually much less extensive than those of honey bees. This is due to a number of factors including: the small physical size of the nest cavity, a single female is responsible for the initial construction and reproduction that happens within the nest, and the restriction of the colony to a single season (in most species). Often, mature bumblebee nests will hold fewer than 50 individuals and are typically found below ground (Figure 43). They sometimes construct a wax canopy over the top of their nest for protection from moisture and insulation. Bumblebees do not often preserve their nests through the winter, though some tropical species live in their nests for several years (and their colonies can grow quite large, depending on the size of the nest cavity). In temperate species, the last generation of summer includes a number of queens who overwinter separately in protect