The Nutritional Needs of Wild Bees: A Study of Pollen ValueThe Nutritional Needs of Wild Bees: A Study of Pollen Value In recent years, the importance of bees as pollinators has become increasingly recognized. However, human activities such as urbanization and agricultural practices are altering the availability and quality of pollen, the primary source of nutrition for bees. To protect the health of wild bees and ensure the preservation of our agricultural systems, scientists have conducted a study to identify the specific plants that provide bees with a balanced and nutritious diet. The study, published in the journal *Boundaries in Sustainable Food Systems*, analyzed the nutritional value of 57 types of pollen found in North America. The researchers collected pollen samples from fresh flowers or dried flowers in the lab, and analyzed the levels of various amino acids, non-esterified fatty acids, and protein-to-lipid and omega-6:3 ratios. Their findings revealed that bees require a diverse diet to meet their nutritional needs. No single plant species can provide all the essential nutrients in the optimal proportions. However, certain plant species emerged as particularly valuable for bees. * Roses, clovers, red raspberries, and tall buttercups were found to have ideal protein-lipid ratios and omega-6:3 ratios, making them highly beneficial for bee health. The study also highlighted the importance of plant diversity. Within the same family, different plant species offered varying nutritional profiles. For example, daisies, a significant source of food for bees, had high levels of essential amino acids compared to other members of the daisy family. Interestingly, the researchers found no nutritional advantage to feeding on endemic plant species over introduced species. This suggests that a variety of non-native plants can still contribute to bee health. The results of this study provide valuable insights into the nutritional requirements of wild bees. By planting a diverse range of flowering plants, including those identified as being particularly nutritious, we can support bee populations and ensure the continued vitality of our ecosystems. Future research should focus on expanding the analysis to include a wider range of plant species and examining the effects of different diets on bee preferences and survival.
THE BUZZ…
To protect wild bees for the future, scientists have identified which plants we can grow to give them a complete, healthy diet
Pollen and bees are highly dependent on each other: Plants need bees to spread their pollen and reproduce, and bees need pollen to eat. (Photo by Krystal Fuller on Unsplash)
WASHINGTON — As important pollinators, bees keep our agricultural systems running — but human-induced changes to the planet are having a major impact on their foraging options. To help protect our food security, we need more information about bees’ own nutritional needs. Scientists sign up Boundaries in sustainable food systems studied the nutritional value of 57 types of pollen and found that bees must forage from a variety of plants to balance their diet between fatty acids and essential amino acids.
“Despite public interest and an increase in pollinator plantings, little is known about which plant species are best suited for bee health,” said Dr. Sandra Rehan of York University, lead author. “This study aimed to better understand the nutritional value of plant species. Based on their ideal protein-lipid ratios for wild bee nutrition, we recommend emphasizing pollen species of roses, clovers, red raspberries and tall buttercups in restoration projects of wildflowers.”
The needs of the bees
Pollen and bees are highly interdependent: plants need bees to spread their pollen to reproduce, and bees need pollen to eat. While bees get their carbohydrates from nectar, pollen provides proteins, lipids, and other essential nutrients. Anthropic changes in the environment that alter the availability and properties of pollen result in malnourished bees.
Bees primarily need to consume high-quality food that contains non-esterified fatty acids, such as omega-6 and omega-3. Without these nutrients, bees live shorter lives, have weaker immune systems, and are less able to cope with environmental stressors. However, if bees consume them in the wrong ratios, they can suffer from cognitive problems. Bees also need essential amino acids, which are necessary for cognitive health and reproduction. However, if they eat too many of them, they may be more susceptible to certain parasites.
To understand which plants are best for bees, the scientists collected pollen samples from 57 species found in North America, either from fresh flowers in the wild or from flowers dried in the lab. They chose the plant species based on their importance to wild northeastern bee species and their prevalence. The pollen was processed and analyzed for levels of various amino acids, non-esterified fatty acids, and protein-to-lipid and omega-6:3 ratios, to determine which plants were best for bees.
The scientists also examined whether closely related plant species provided similar nutritional benefits, and whether species introduced to the area where they were collected were less nutritious than endemic species.
Healthy eating habits
In general, plants within the same family provided the bees with very different nutrients than other members of the same family, with the exception of essential amino acids. Plants in the cabbage family, the legume family, and the daisy family all had similar levels of essential amino acids compared to other plants within the same family. Daisies, a very important plant for foraging bees, had particularly high levels of essential amino acids. Interestingly, plants high in essential amino acids were relatively low in non-esterified fatty acids, and vice versa.
“There is a potential trade-off between the fatty acid and amino acid content of pollen, suggesting that bees may benefit more from a varied floral diet than from a single pollen source,” says Rehan. “No plant species is optimal for the overall health of wild bees.”
The scientists’ results indicated that feeding on a wide variety of flowers is best for most bees, and that feeding on endemic plant species offers no nutritional advantage. Most pollen species contain most of the necessary nutrients, but to get the optimal amount of nutrients in their diet, bees would need to forage on a variety of plant species. The scientists suggested that this diversity of nutrient content reflects the varying needs of different bee species, especially specialized species that prefer certain plants. A wide variety of food sources with different properties ensures that all bees can forage on the plants that best nourish them.
“We hope this work will help guide the selection of flowering plants for pollinator gardens,” says Rehan. “But here we only studied 57 plant species, and there are thousands more we need to study to understand their nutritional profiles. We hope this will inspire future similar research, as well as follow-up studies on bee preferences and survival with different diets.”
–Borders
via EurekAlert!
