Pollen: Why do bees and humans want it?
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Pollen: What is it?
We see pollen coming into the hive packed on the honey bees’ hind legs, we see it as a kaleidoscope of color packed in the cells of a frame of comb, but what is it really and why do the bees collect it. A basic answer is that pollen is the primary nutritional source for bees and is gathered during their foraging. It is crucial for their diet, providing proteins, fats, vitamins, minerals and needed to produce royal jelly.
Pollen is also a valuable apitherapeutic (therapeutic honey bee) product and is considered a nutritional healthy food appreciated by natural medicine from ancient times. Recently, pollen has been considered a beneficial food supplement and a value-added product that contains approximately 250 different bioactive components. It contains numerous beneficial elements such as Mg, Ca, Mn, K, and phenolic compounds. Pollen also possesses strong antioxidant, anti-inflammatory, antimicrobial, antiviral, analgesic, immunostimulant, neuroprotective, anti-cancer, and hepatoprotective properties.
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Pollen grains are the male reproductive part of the flowering plants. In the 17th century, the term pollen was established from a Latin word which means fine powder or flour. For centuries, this plant component has been known as a “food” with biological functions. Foragers shape field-gathered pollen into pellets and transport it to the hive that produces a high-quality food product called bee bread.
Approximately 50 to 250 grams of pollen can be collected by foragers of one colony per day, while 14 to 40 kilograms of pollen can be collected each year. Two pollen pellets have a combined total mass near 20 mg, which is more than 25% of the average body mass of the honey bee. Bees that collect pollen do not consume pollen from the flower, but they take it for the consumption of their offspring in the hive and behave as social bees.
During foraging the bees add regurgitated fluid with the pollen grains to facilitate pollen adherence to the pollen baskets or corbicula, which are shallow recesses on the tibia of their hind legs with the hair turned inward helping to hold the pollen in place. Pollen is collected by adult forager bees and transported to the hive. The flightless nurse bees fragment the mixture of collected pollen, saliva, honey, digestive enzymes, and lactic acid, which is then stored in wax honeycomb cells.
The pollen in the wax combs undergoes anaerobic lactic fermentation breaking the grain wall during the ripening process, which is caused by bacteria (e.g., Lactobacillus spp., Pseudomonas spp.) and yeasts (Saccharomyces spp.). Once fermented it is referred to as bee bread or fermented pollen and covered with a thin layer of wax and honey. Honey bees rely on this fermented pollen for proteins, lipids, fatty acids, sterols, carbohydrates, and vitamins.
Beekeepers passing a hive at the heat of the day might smell the results of this fermentation as a sweet aroma in the air similar to the smell of baked bread.
Types of Pollen
Honey bees are incredible pollinators that collect a wide variety of pollen from different sources. As they fly from flower to flower, tree to tree, and grass to grass, they gather a diverse range of pollen types. The three main categories of pollen collected by bees include tree pollen, grass pollen, and flower pollen.
Tree pollen is one of the primary sources of nutrition for bees, particularly in the spring when flowers are scarce. Trees such as oak, maple, and willow are favorite pollen sources for their bees. In fact, research has shown that honeybees collect over 70% of their pollen from tree sources.
Grass pollen is another important component of a bee’s diet, especially during the summer months when grasslands are in full bloom. Bees also collect pollen from various types of flowers, including clover, alfalfa, and sunflowers. A typical beehive can process over 100 pounds of pollen per year, which is essential for their growth, reproduction, and overall health.
The dietary component of pollen grains differs strongly among various plant species and is directly related to honey bee health. Honey bees and bumble bees detect and make decisions about foraging based on the nutritional content of floral resources. According to the research, honey bees have a preference to collect pollen from 2 to 8 plants every single month. Pollen with small amounts of protein content can have adverse effects on the health of bees, such as reducing hypopharyngeal gland size in adult honey bees resulting in lower royal jelly production, low larval weight in bumblebees (Bombus terrestris), sweat bees (Lasioglossum zephyrum) offspring weight, and immune function in honey bee colonies. By understanding the different types of pollen collected by bees, beekeepers can better manage their hives to ensure a diverse diet for their pollinators.
Honey Bee Health
When bees collect pollen from flowers, it provides them with the necessary protein, vitamins, and minerals required for development and growth. Pollen is rich in amino acids, which are essential for building and repairing muscles, organs, and tissues within the bee’s body. Without sufficient pollen intake, bees may experience stunted growth, weakened immune systems, and reduced lifespan.
A healthy diet of pollen also maintains the overall health and vitality of a bee colony. When pollen from diverse sources is consumed by the worker bees, it contributes to their energy levels, reproductive success, and longevity. As a result, colonies thrive when bees have access to an abundant supply of high-quality high-protein pollen.
Pollen deficiency or scarcity can also have devastating consequences for honeybee populations. Insufficient protein intake may lead to increased mortality rates among worker bees and reduced brood production. This, in turn, affects the colony’s ability to store food reserves, reproduce, and defend against diseases and pests.
Essential Diet
There are 20 biogenic amino acids, but honey bees require only 10 amino acids that are essential to their diet. Different plant origins of pollen grains contain all essential amino acids in fewer amounts. Except for nutrition, honey bees use those amino acids for maintaining individual immunity and social behavioral patterns. Pollen is also their main protein source, and its digestibility and quality are important nutritive factors that impact hypopharyngeal gland size, royal jelly production, and so could affect queen reproductive capability. The most important elements of honey bee nutrition are carbohydrates, proteins, amino acids, and lipids, all of which have a significant impact on individual and colony health. The nutrition value of these (carbohydrates, proteins, amino acids, and lipids) contents of some pollen types varies between species.
Fermented bee pollen also has the added benefit of inhibiting the growth of harmful bacteria such as Melissococcus plutonius (European foulbrood) and Paenibacillus larvae (American foulbrood) due to the presence of dodecanoic acid, linoleic acid, myristic acid, and linolenic acids. There is a correlation between the reproduction of honey bee colonies and the protein content found in pollen. Honey bees that collect pollen with high protein content tend to have higher colony reproduction rates and bee brood production.
Pollen collected from plants that bloom during the spring season contains a higher protein content (average of 24.2%) compared with those that bloom during the summer and autumn seasons (average of 19.3 and 20.5%, respectively). During the spring season, pollen containing protein content of more than 27% enables honey bee colonies to enhance their reproduction.
Metabolites
Bee pollen metabolites include proteins, amino acids, enzymes, co-enzymes, carbohydrates, lipids, fatty acids, phenolic compounds, bio-elements, and vitamins. The mean percent of protein in pollen is 22.7%, including vital amino acids such as tryptophan, phenylalanine, methionine, leucine, lysine, threonine, histidine, isoleucine, and valine. These amino acids are not synthesized in our bodies, but they play an important role in optimal growth and health. And for their vital engagement in gene expression, cell signaling pathways, digestion, and nutrient absorption, they must be included in the diet. Nucleic acids, particularly ribonucleic acid, are present in considerable amounts. As a source of energy, carbohydrates exist in bee pollen at 30.8%. About 5.1% of lipids are found in bee pollen as essential fatty acids like archaic, linoleic, and γ-linoleic acids, phospholipids, and phytosterols (in particular β-sitosterol). Phenolic compounds represent an average of 1.6% of pollen content, including leukotrienes, catechins, phenolic acids (e.g., chlorogenic acid), and flavonoids (e.g., kaempferol, isorhamnetin, and quercetin) [10].
The essential substances, including vitamins and bio-elements, are present in 0.7% of the whole material. Bee pollen is a potential source of fat-soluble vitamins like vitamin E, pro-vitamin A, vitamin D, and water-soluble vitamins such as vitamins B1, B2, B6, and C, also a source of acids like biotin, rutin, pantothenic, nicotinic, inositol, and folic. Bio-elements include macro-elements like sodium, magnesium, calcium, phosphorus, and potassium, as well as micro-elements as zinc, copper, manganese, iron, and selenium. These metabolites contribute to the therapeutic potential of bee pollen.
Although bee pollen contains many metabolites, previous studies have indicate a limited utilization of the bee pollen ingredients due to the presence of a robust outer shell layer called exine. When pollen reaches the gastrointestinal tract, the grains swell due to absorption of water and activation of the enzymes. The components of pollen grain walls (pigments, enzymes, and allergens) are diffused in the acid medium of the stomach. The inner layer of the grain wall protrudes outside, forming a germination tube shape. Pollen grains break and deliver starch grains that are coated by protein lamella Digestion of pollen proteins, carbohydrates, and lipids occurs under the control of gastrointestinal (GI) enzymes. Fatty acids, amino acids, vitamins, and sugars undergo normal desorption processes. Pollen can enter blood flow directly from the GI tract.
Pesticides
Honey is a natural food with many pro-health properties, which comprises a wide variety of valuable ingredients. It can also be the source of chemical contaminants of environmental origin, including persistent organic pollutants (POPs) that can contribute to adverse health effects to humans. Monitoring the degree of pollution of honey/bee products with hazardous chemicals is important from a nutraceutical point of view. Nutraceutical is a pharmaceutical effect from plant extracts, compounds, food products which have efficacy and therapeutic influence on clinical outcomes and patient care largely through supplements.
Recent literature data on chemical pollutants in honey/bee products originating from the environment have shown that honey/bee products sampled from urban and industrialized areas were more contaminated than samples from ecological and rural locations. More pollutants were usually detected in propolis and bee pollen than in honey. Based on research and regulations, it’s believed that most of the toxic pollutants of environmental origin in honey/bee products are at levels that do not pose a threat to the health of the potential consumer. This does not mean that pesticides and other chemicals are not present.
Health Risks
Bee pollen, often referred to as “nature’s multivitamin,” is rich in amino acids, minerals, vitamins, and antioxidants and is associated with potential health benefits. Alongside its beneficial properties, pollen also possesses environmentally hazardous contaminants such as pesticides, toxic elements, and other health risk factors, which can be dangerous both for bee’s life and indirectly for public health. It can also trigger serious allergic reactions in some individuals, such as itching, redness, upset stomach, and shortness of breath, particularly for those with known allergies. Although it is considered safe for most people, caution is advised so consulting a doctor before starting bee pollen is recommended.
Pollen Collection Impact
Beekeepers collect bee pollen for three primary reasons: high-quality protein for their bees, making pollen patties when there is no pollen or nectar available, and the market for bee pollen. Collecting bee pollen involves using specialized traps placed at the hive entrance to collect pollen pellets from foraging bees. Timing and frequency are crucial, as too frequent harvesting can negatively impact overall health of the hive and colony population. High-quality pollen in late summer is crucial for maintaining a robust bee population during winter. Pollen substitutes, such as soy pollen and skim milk powder, may not match the nutritional value of freshly gathered flower pollen. And even though honey bees produce an excess of honey, their pollen collection must be managed carefully. Proper planning, equipment, and regular trap maintenance are essential to minimize stress on bees and avoid disrupting brood production. As bee populations dwindle, understanding the practical and nutritional value of bee pollen is essential.
Harvesting Pollen
Harvesting bee pollen involves several key steps that ensure a quality product while protecting bee health. Beekeepers use specific techniques and tools to gather pollen responsibly.
Beekeepers prepare the hives by placing pollen traps at the entrance. These traps collect pollen as bees enter and exit the hive. The traps are designed not to obstruct the bees’ movement extensively. After bees collect pollen from flowers, they return to the hive with pollen sacs on their legs. The traps feature small screens or surfaces that scrape off some of the pollen from these sacs. This collection process usually occurs during peak flowering seasons when pollen availability is high. Harvesting occurs typically in the late morning, when pollen collection is at its peak. At this time, bees are actively foraging for nectar and pollen, ensuring the traps fill efficiently. Beekeepers collect pollen regularly, usually every few days or weekly, depending on the hive’s pollen production.
Once collected, pollen undergoes cleaning and drying by the beekeeper. Cleaning removes any debris, while drying lowers moisture content preventing mold and preserving freshness. Drying is done for a longer period at room temperature in special driers. This helps to prevent microbial spoilage and rapid fermentation, resulting in easy marketability and increased revenue for beekeepers. Furthermore, pollen with high moisture content easily spoils in a short period after harvesting because it is highly vulnerable to microbial attacks. After drying, pollen is packaged in airtight containers to maintain quality and freshness. Proper storage conditions, such as cool temperatures and low humidity, extend the pollen’s shelf life.
Sustainable beekeeping practices ensure bees are not over-harvested. Beekeepers monitor hive health regularly and only collect what does not harm the colony. This balanced approach supports bees and provides high-quality pollen for consumers. By following these steps, beekeepers harvest bee pollen efficiently while fostering healthy bee populations. This responsible approach protects essential pollinators and provides consumers with a nutritious product.
Referenced Materials
- Bee Pollen – An Overview
- Pesticide Contamination in Native North American Crops, Part I—Development of a Baseline and Comparison of Honey Bee Exposure to Residues in Lowbush Blueberry and Cranberry
- Can Gathering Pollen From Bees Hurt The Bees?
- Bee Pollen: Current Status and Therapeutic Potential
- Bee pollen as a food and feed supplement and a therapeutic remedy: recent trends in nanotechnology
- Pollen Collection, Honey Production, and Pollination Services: Managing Honey Bees in an Agricultural Setting
- Tom Seeley’s book “The Wisdom of the Hive”
- Review of harmful chemical pollutants of environmental origin in honey and bee products
- Food safety hazards of bee pollen – A review
- Impact of landscape composition on honey bee pollen contamination by pesticides: A multi-residue analysis
- New Data Confirm Catastrophic Honey Bee Colony Losses, Underscoring Urgent Need for Action
- Attractiveness of Agricultural Crops to Pollinating Bees for the Collection of Nectar and/or Pollen
- How Bee Pollen is Harvested: A Simple Guide to the Process
- Unlocking Beekeepings Secret Power: Pollen Harvesting Guide
- Bee Pollen: Chemical Composition and Therapeutic Application
- Bee Pollen Carbohydrates Composition and Functionality
- Composition and functionality of bee pollen: A review
- Environmental Impact Of Bee Pollen Harvesting
- Pollen Source Affects Development and Behavioral Preferences in Honey Bees
- How Honeybees Collect and Use Pollen in Their Nutrition
- Honeybee nutrition and pollen substitutes: A review
- Gauging the Effect of Honey Bee Pollen Collection on Native Bee Communities
- Beebread pollen composition is affected by seasonality and landscape structure
- Honey bees as biomonitors of environmental contaminants, pathogens, and climate change
- CSI Pollen: Diversity of Honey Bee Collected Pollen Studied by Citizen Scientists