The bumblebee, belonging to the genus Bombus, is recognizable by its stout, round body covered in dense, soft hair called pile. This fuzzy coat helps the bee regulate body temperature, allowing it to fly in cooler conditions than many other insects. Found primarily across the temperate zones of the Northern Hemisphere, these insects are foundational to many ecosystems, serving as generalist pollinators for both wildflowers and numerous food crops.
Pollination and Buzzing Behavior
The bumblebee’s primary function is to facilitate plant reproduction by moving pollen, a process it executes with a specialized technique known as buzz pollination. This mechanism allows them to access pollen tightly held within the anthers of certain flowers, which are often structured with small apical pores or slits. The bee lands on the flower, grasps the pollen-producing structure, and then engages its powerful indirect flight muscles.
By rapidly contracting these muscles, the bee vibrates its entire body, transmitting a powerful resonance directly into the flower. This vibration, which can reach frequencies around 270 Hz, forcibly dislodges the pollen, causing it to shoot out of the anthers in a cloud. This method is the most efficient way to pollinate crops such as tomatoes, blueberries, and cranberries, which hold their pollen tightly. The bumblebee’s larger body and strong musculature make it a superior pollinator for these specific plants compared to the honeybee, which cannot generate the required frequency.
The Annual Life Cycle
Bumblebee colonies operate on an annual cycle; the entire nest, except for new queens, dies out each year. The cycle begins in the early spring when a single, newly mated queen emerges from hibernation. She spends several weeks foraging to replenish her energy reserves while searching for a suitable nest site, often an abandoned rodent burrow or a cavity under a grass tussock.
Once a nest is established, the queen constructs a small wax cell and lays her first batch of eggs, which she incubates with her body heat. These first offspring develop into female worker bees, a process that takes about four to five weeks from egg to adult. After the first workers emerge, they take over foraging and nest maintenance, allowing the queen to remain in the nest to focus solely on laying eggs.
The colony grows throughout the summer, reaching a maximum size that can range from 50 to 500 individuals depending on the species. Toward the end of the season, the queen begins laying eggs that develop into unfertilized males and large, fertilized new queens. These new reproductive members leave the nest to mate, after which the males die. The newly fertilized queens feed intensively to store fat reserves before seeking a sheltered location to hibernate and restart the cycle the following spring.
Foraging and Colony Maintenance
The workers’ activity revolves around collecting resources and maintaining the nest environment. Worker bees forage for two primary substances: nectar, a sugar-rich liquid that serves as the colony’s fuel, and pollen, which provides the protein needed to feed the developing larvae. As they visit flowers, they comb the pollen that collects on their hairy bodies into specialized structures called corbiculae, or pollen baskets, located on their hind legs.
Back at the nest, the collected nectar and pollen are stored in small, cup-like structures made of wax, often repurposed from old larval cocoons. The workers perform housekeeping tasks, such as removing dead bees and larvae to prevent the spread of disease. To create a stable microclimate, the bees utilize materials they find in the environment to line and insulate their nest cavity. The nest is typically covered by finely shredded grass, moss, animal fur, or similar materials, which helps maintain the temperature necessary for the brood to develop.