How Bees Get Pollen From Flowers

Why flowers offer pollen

Pollen is the fine powdery material produced by a flower’s anthers, the parts of the male reproductive organs. It contains the male reproductive cells needed for plant reproduction. For many flowering plants, a pollen grain must reach a compatible stigma—the receptive tip of a flower’s female reproductive organ—before fertilization can occur and seeds can develop.

Plants use different ways to move pollen. Some release it into the wind, while others rely on animals, including bees. A flower visited by a bee may provide nectar, pollen, or both. Nectar is a sugary liquid that bees use as food; pollen supplies protein, fats, minerals, and other nutrients, especially important for feeding developing larvae.

Flowers can attract bees with color, scent, shape, and food rewards. Their structures also influence where pollen touches a visitor. A bee reaching into a flower for nectar may brush against anthers and pick up grains without setting out to do so.

How pollen sticks to a bee

A bee’s body is covered in hairs, many of them branched or featherlike. These hairs provide numerous contact points where pollen grains can catch as the bee moves among a flower’s parts. A bee may also become electrically charged as it flies, while flower surfaces can carry a different charge; electrostatic forces can help pollen move across the small gap to the bee.

Not all pollen ends up in the same place. Some remains on the bee’s head, thorax, or abdomen, depending on the flower’s shape and the bee’s movements. Pollen that stays on exposed hairs can be especially likely to brush against the stigma of another flower. That transfer is pollination: moving pollen to a receptive part of a flower, not simply collecting it.

A bee visiting a flower can therefore do two things at once: gather food and, sometimes, deliver pollen. It is not guaranteed that every visit pollinates a flower. The pollen must reach a suitable stigma, and the plant and bee must be compatible in ways that allow reproduction.

How bees pack and carry pollen

Bees groom themselves with their legs and mouthparts, moving pollen from parts of the body that are difficult to reach. In many familiar bees, including honey bees and bumble bees, pollen is packed onto specialized areas on the hind legs. Honey bees have smooth, slightly concave areas bordered by stiff hairs, often called pollen baskets or corbiculae. Other bee species carry pollen in dense hairs called scopal hairs, which may be on the legs or underside of the abdomen.

To make a load, a bee moistens and presses pollen grains together, often with a little nectar. The resulting pellet is easier to transport than loose grains. On a honey bee, the two pollen baskets can become visibly loaded with colored pellets; the color depends on the flowers visited. The bee returns to the colony with this pollen, which can be stored and used as food.

Grooming and packing create an important trade-off. Pollen moved into a compact load is less likely to brush off onto flowers, making it useful as food but often less available for pollination. Some pollen remains loose on the body or in places the bee does not groom completely, so it can still be transferred during later visits.

From flower visit to pollination

When a bee moves from one flower to another, loose grains on its body may contact anthers or stigmas. If pollen reaches a receptive stigma of the same species, it may continue through the flower’s reproductive process. In many plants, successful fertilization eventually leads to seed formation; in plants that produce fruit, the ovary may develop into the fruit surrounding those seeds.

Flower design affects how likely this transfer is. A bee entering a tubular flower may touch pollen-bearing structures in a particular spot, while an open flower may dust its body more broadly. Some flowers release pollen only when a bee vibrates its flight muscles against the flower, a behavior often called buzz pollination. Bumble bees use this technique on certain plants, including tomatoes and blueberries; ordinary honey bee visits do not perform this specialized vibration in the same way.

Bees are not the only pollinators, and plants do not all depend on bees. Wind-pollinated plants such as many grasses release pollen into the air. Other flowers are visited by butterflies, flies, beetles, birds, or bats. The bee’s contribution is especially useful when its behavior and body fit the flower’s way of transferring pollen.

Why pollen collection differs among bees

Bee species differ in body size, hairiness, grooming behavior, and the places where they carry pollen. Honey bees are social and bring pollen back to a shared nest. Many bumble bees also live socially and transport pollen on their hind legs. Many solitary bees provision individual nest cells, carrying pollen there to feed their offspring.

Some bees specialize in collecting pollen from a narrow range of plants, while others visit a broader variety. Their body features and flower preferences can make them particularly effective visitors to certain flowers. A flower’s shape may also favor some bee sizes or behaviors over others.

Honey bees often pack pollen into baskets, which makes their loads easy to see, but that does not mean they are the only bees that collect pollen. Nor does a loaded pollen basket mean the bee has stopped pollinating: grains can remain elsewhere on its body and transfer during visits.

Common misconceptions about bee pollen

“Pollen” and “nectar” are not interchangeable. Bees gather nectar mainly as a carbohydrate-rich energy source, while pollen provides a different mix of nutrients. A bee may collect one, the other, or both during a foraging trip, depending on its needs and what a flower offers.

Another misconception is that bees deliberately pollinate every flower they visit. Their immediate purpose is usually to gather food. Pollination is a result of pollen moving between flower structures, and the outcome depends on whether grains reach a suitable flower. Likewise, pollen stuck to a bee is not automatically being carried to the hive: some may be left behind, groomed away, or gathered into a load.

Frequently Asked Questions

Do bees eat pollen?

Yes. Bees use pollen as food, particularly as a source of nutrients for developing young. Worker bees may collect and store it in the nest or hive, where it becomes part of the colony’s food supply.

How do bees carry pollen on their legs?

Many bees groom pollen onto specialized hairs or structures on their hind legs. Honey bees pack it into pollen baskets bordered by stiff hairs; other bees carry it among dense scopal hairs.

Does pollen hurt bees?

Pollen is a normal food resource for bees, and pollen grains routinely cling to their bodies during flower visits. A bee gathering pollen is carrying food, not being harmed simply because grains are attached to it.

Do all bees pollinate flowers?

Bees can pollinate flowers when pollen on their bodies reaches a compatible stigma. The chance and effectiveness of transfer vary with the bee, the flower’s structure, and the bee’s behavior.

What is the difference between pollen and nectar?

Pollen is produced by a flower’s anthers and supplies nutrients such as protein. Nectar is a sugary liquid produced by flowers that bees use chiefly as an energy source.

Further reading: U.S. Forest Service. Details can change, so check the official page for anything that matters to you. Spotted a mistake? Tell us. How we write an answer.