Bumble bees are important pollinators that contribute to the health of many ecosystems, including gardens. Attracting these fuzzy insects to a garden involves providing a combination of resources they need for survival and reproduction. Understanding their preferences for flowers, food, nesting sites, and environmental conditions can help create a thriving habitat for them.
Flower Characteristics
Bumble bees are drawn to specific visual and olfactory cues in flowers. They exhibit preferences for certain colors, notably blue, purple, yellow, and white, while red flowers are largely invisible to them. Instead of red, bees perceive a spectrum that includes blue-green, blue, violet, yellow, orange, and a unique “bee’s purple,” which is a combination of yellow and ultraviolet light. This means that flowers with UV patterns, often invisible to the human eye, can serve as landing guides, directing bees to nectar sources.
The shape of a flower also influences a bumble bee’s ability to access nectar and pollen. Open, tubular, or bell-shaped flowers are generally preferred, allowing easy entry. Some bumble bee species, particularly those with longer tongues, are adapted to reach nectar deeper within flowers. Floral scents are another significant attractant, with bees being drawn to sweet, herbal, or spicy fragrances that signal a high-energy nectar reward. Flowers emit complex mixtures of volatile compounds, and bees can even distinguish between different flowers based on the unique arrangement of these scents.
Essential Food Sources
Bumble bees require two primary nutritional components from flowers: nectar and pollen. Nectar serves as their main source of carbohydrates, providing the energy needed for flight and other activities. While adult bees primarily consume nectar for energy, they also collect pollen.
Pollen is a rich source of protein, fats, vitamins, and minerals, which are all necessary for the growth and development of larvae and the overall health of the adult bees. Worker bees gather pollen in specialized “baskets” on their hind legs and transport it back to the nest to feed the young. Bumble bees are selective in their pollen choices to meet their nutritional needs.
Nesting and Shelter Needs
Bumble bees seek undisturbed, sheltered locations for nesting and raising their young. Many species prefer underground sites, often utilizing abandoned rodent burrows. These burrows offer ready-made, insulated spaces that protect the developing colony. Other common nesting areas include dense grass clumps, mossy vegetation, or compost piles. Some species may also nest above ground in cavities such as old birdhouses, roof spaces, or wall cavities.
A suitable nest site provides insulation and protection from the elements, remaining dry and avoiding excessive heat from direct sunlight. Queens typically look for dry, enclosed spaces that already contain some insulating material. While bumble bees do not create or dig their nests themselves, they adapt existing cavities.
Environmental Conditions
Beyond specific food and nesting sites, bumble bees benefit from broader environmental factors in a garden. Access to clean water sources is important for their hydration. Shallow puddles or bird baths with landing spots can provide this.
Bumble bees are active in a wider range of temperatures compared to many other bee species. They can forage in cooler conditions. Their ability to shiver their flight muscles to generate heat allows them to maintain a body temperature suitable for flight even when ambient temperatures are low. While they are tolerant of cooler weather, extreme heat can reduce their activity and foraging efficiency. Protection from strong winds and direct, intense sun can also contribute to a more hospitable environment, especially around nesting sites.