Bees, found across nearly every continent, exhibit a wide range in size, reflecting the diversity of over 20,000 known species. From minuscule to surprisingly large, bee dimensions vary considerably. This spectrum of sizes influences their roles within ecosystems and highlights their intricate adaptations.
The World’s Largest Bee
The largest known bee species is Megachile pluto, commonly known as Wallace’s Giant Bee. This bee is primarily found in Indonesia’s North Moluccas islands. Female Wallace’s Giant Bees can reach a body length of up to 1.5 inches (38 mm) and boast a wingspan exceeding 2.5 inches (63.5 mm). Their prominent, stag beetle-like mandibles are particularly large in females.
Female Wallace’s Giant Bees use their large mandibles to gather tree resin and wood fibers. They construct nests within active arboreal termite nests, lining tunnels with sticky resin to deter termites. Discovered in 1858 by Alfred Russel Wallace, the species was thought lost until its rediscovery in 1981 and subsequent sightings in 2019. Its preference for primary lowland forests makes it vulnerable due to habitat loss from palm oil plantations.
Common Bee Sizes
While Wallace’s Giant Bee represents the upper limit of bee size, most commonly encountered species are much smaller. European honeybees (Apis mellifera) measure between 0.5 to 0.75 inches (12.7 to 19 mm) in length. Within a honeybee colony, queens are the largest, followed by drones (males), and then worker bees, which are the smallest.
Bumblebees (Bombus species) are generally larger and stouter than honeybees, with many species ranging from 0.5 to 1 inch (12.7 to 25.4 mm). Some large bumblebee species, like the Chilean bumblebee (Bombus dahlbomii), can reach up to 1.6 inches (40 mm). The smallest bee in North America, Perdita minima, measures less than 0.08 inches (2 mm) long.
Factors Influencing Bee Size
Biological and environmental factors contribute to bee size variation, both across and within species. Genetics play a fundamental role, as inherited traits determine a species’ potential size range. Different bee species have evolved distinct average body sizes reflecting their unique adaptations and ecological niches.
Nutrition, particularly during the larval stage, is a factor determining an individual bee’s final size. Larvae that receive a richer diet, abundant in protein and carbohydrates from pollen and nectar, generally grow larger. For social bees like honeybees, the quality and quantity of food provided by worker bees to developing larvae, such as royal jelly for queen larvae, directly influences adult size and caste. Environmental conditions, including temperature and the availability of floral resources, also affect bee development and size; higher temperatures during larval development can lead to smaller adult body sizes. The specific role a bee plays within its colony, such as a queen, worker, or drone, also corresponds to size differences.