Native Bee Nutrition

Native bees, like any other animal, require essential nutritional ingredients for survival and reproduction.

Our native bees require carbohydrates (sugars in nectar or honey), amino acids (protein from pollen), lipids (fatty acids, sterols), vitamins, minerals (salts), and water. Additionally, these nutrients must be present in the right ratio for native bees to survive and thrive.

Read more: Should You Feed Native Bees?

  Pollinator Syndrome

Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic (wind and water) or biotic, such as birds, bees, flies, and so forth. These traits include flower shape, size, color, odor, reward type and amount, nectar composition, timing of flowering, etc.

For native bees, these are the typical characteristics:

• Color: Bright white, yellow, blue or UV
• Nectar Guides: Present
• Odor: Fresh, mild, pleasant
• Nectar: Abundant, somewhat hidden
• Pollen: Limited, often sticky, scented
• Flower Shape: Shallow, landing platform, tubular

Try the quiz: Pollinator Flower Color Preferences

  Carbohydrates

Like other animals, native bees need carbohydrates as an energy source. All carbohydrates are first converted to glucose, the fuel in nearly all cells. Carbon dioxide and water are created as by-products. Aside from being used as an energy source, glucose can also be converted to body fats and stored. A native bee needs 11 mg of dry sugar each day.

  Collection of Nectar

Nectar is the main source of carbohydrates in the natural diet of native bees. Sugar concentration in nectar can vary widely, from 5% to 75%, although most nectar is in the range of 25% to 40%. A native bee uses her proboscis to suck up nectar from flowers and stores the liquid in her crop.

The crop is a specialized part of the digestive system, and has a structure between it and the midgut, where digestion takes place. This structure can let some nectar in when the forager needs energy on its way home.

  Protein

Pollen provides bees with protein, minerals, lipids, and vitamins. All animals need essential amino acids, which must be obtained externally and cannot be synthesized by animals. Native bees also need the same 10 amino acids as other animals, including humans. These amino acids are obtained from pollen.

Native bees do not intentionally carry out pollination; it is the unintended result of the bee’s travels. Pollen clings to the branched and sticky hairs of the bee's body, and is rubbed off as the bee walks or flies from one blossom to another. Native bees carry pollen in order to transport it back to their nests. Pollen is stored in various forms, usually for feeding to the bees' young after they hatch. In most wild bee species, the females are responsible for carrying and storing pollen.

Males of many species drink nectar from flowers, but lack attributes that allow them to transport pollen efficiently. ​ Female bees of varying species have evolved singular methods of transporting pollen. Female bumble bees, for example, carry pollen in baskets called corbiculae. A corbicula is made up of hairs blended together to form a concave shape.

Most wild bees lack pollen baskets. Instead, many wild female bees have specialized leg hairs called scopae that are particularly long or sticky. Often, the hairs on bees' legs, bodies and faces have a slight electrostatic positive charge; negatively-charged pollen is thus attracted to the hairs.

  Steroids and Lipids

A sterol, 24-methylene cholesterol, is common in pollen and is the major sterol source for native bees. Nearly all insects need to obtain sterol from their diet because of their inability to synthesize them directly. Sterol is the precursor for important hormones such as molting hormone, which regulates growth because it is required at the time of each molt. It is not clear what other lipids are required by native bees, but most likely normal consumption of pollen provides for all the lipid requirements.

  Vitamins

Like sterol and lipids, the vitamin needs of native bees are satisfied if pollen is abundant. It is not known whether micro-organisms naturally present in the alimentary canal of bees may play a role in providing vitamins and other essential substances.

  Minerals

The mineral requirements of native bees are poorly understood. High amounts of potassium, phosphate, and magnesium are required by all other insects, and so presumably are by native bees as well. Excessive levels of sodium, sodium chloride, and calcium have been shown to be toxic to bees. Again, all the required minerals can be obtained from pollen, although nectar also contains minerals.

  Water

Native bees typically collect water from nearby water sources.