A bumblebee is any of over 250 species belonging to the genus Bombus, characterized by their robust, hairy appearance. They are widely distributed, primarily found in temperate climates across the Northern Hemisphere, with some presence in South America. Understanding a bumblebee’s physical traits is key to recognizing this common pollinator.
Overall Build and Size
Bumblebees are notably stocky insects, possessing a characteristically round and barrel-shaped body. Their most defining feature is the dense covering of soft, branched hairs, known as the pile, which makes them appear remarkably fuzzy. This thick hair allows them to remain active in cooler temperatures and higher altitudes than many other bee species.
The size of a bumblebee is highly variable, depending on the species and the individual’s caste (queen, worker, or male). Queen bumblebees are the largest, sometimes reaching up to 0.9 inches (22 mm) in length. Workers and males are typically smaller, often ranging between 0.4 and 0.7 inches long. This size variation can even be seen among worker bees within a single species.
Detailed Body Segments
The bumblebee’s structure is divided into three distinct sections: the head, the thorax, and the abdomen. The head contains two large compound eyes and three simple eyes (ocelli), which help the bee detect light intensity and ultraviolet light. Their sensory antennae are relatively short and L-shaped, used for detecting odors and for tactile navigation.
The middle segment, the thorax, is the center of motion, where two pairs of translucent wings and three pairs of legs are attached. The forewings and hindwings hook together to operate as a single pair during flight. A specialized feature on the hind legs of female workers and queens is the corbicula, or pollen basket. This smooth, concave area surrounded by a fringe of hairs is used to compact and carry pollen back to the nest.
Coloration and Pattern Variation
Bumblebee markings consist of alternating bands of black and bright colors, which serve as warning coloration to potential predators. These colors are derived entirely from the dense hair (pile) covering the body, not the underlying exoskeleton. The bright colors typically include shades of yellow, orange, or white.
The specific pattern and number of these color bands are crucial for identifying different species. The tail end of the abdomen can also be a distinct color, such as white, red, or buff, further contributing to the species-specific appearance. This high degree of variation in color patterns is used by entomologists to distinguish between the many species within the Bombus genus.
Distinguishing Bumblebees from Look-Alikes
Bee Look-Alikes
Bumblebees are often confused with other insects that mimic their appearance, most commonly honey bees and carpenter bees. A key difference lies in the body hair: bumblebees are significantly more robust and densely hairy, giving them a much fuzzier look than the relatively slender honey bee. Carpenter bees, while also large, often have a smooth, shiny, black abdomen that appears nearly bald, unlike the fully-furred bumblebee abdomen.
Fly Mimics
The easiest way to distinguish a true bee from a fly mimic, such as a hoverfly, is by the wings and eyes. Bumblebees have two pairs of wings (four total), whereas flies only have one pair (two total). Additionally, flies often have disproportionately large eyes that meet or nearly meet on the top of the head. This feature is not seen in bumblebees, whose eyes are smaller and set further apart.