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Apiculture and Pollinator Program

Pollinators & Honey Bees Importance

The Importance of Pollinators

Plants are the most prolific and important primary producers on Earth. Through photosynthesis, they capture energy from the sun and convert it into organic molecules such as sugars. These energy rich molecules are the fuel for Life, and plants supply the majority of these compounds for the rest of the living organisms on Earth. Without plants, most other organisms, including us, would not be able to survive.

As with all living things, plants must reproduce. Many plants can reproduce vegetatively. For instance, many aquatic plants can grow shoots that break-off and are carried by currents to new locations where they establish and grow, but this form of reproduction only produces clones that are identical to the mother plant. If environmental conditions change, these clones may not be adapted to survive the new conditions. To ensure survival of their offspring in a world with constantly changing environments, most plants also reproduce sexually to instil diversity into their progeny. Sexual reproduction is the process by which an organism combines its genes with another related organism to form offspring that share traits of both parents. The "shuffling" of genes between the two parent plants, increases diversity among their offspring which increases the likelihood that some will survive even if conditions change.

History

The earliest plants, such as algae, mosses, and ferns, relied mainly on water and wind to carry sperm cells from one plant to another. When the gametes (sex cells) combined, they would form a developing embryo that would have to have suitable growing conditions to develop and survive. One group of plants evolved seeds, which are able to survive for long periods of time until proper growing conditions occur. These early seed producing plants are the Gymnosperms and include the conifers, cycads, and Ginkgo. They were the first plants to produce pollen, but, like the ferns and mosses, they still relied on wind to transfer pollen. This left them at the mercy of the climate.

About 140 million years ago, a new group of plants evolved. These plants produce seeds like the Flower Anatomygymnosperms, but the ovary where the seeds develop is protected in a carpel housed in a specialized structure called the flower. Flowers are basically specialized sex organs which help to protect and control the conditions around the developing seeds. The development of the flower drove speciation among the angiosperms, allowing them to diversify and explore other methods of transferring pollen. Some angiosperms developed traits that attracted insects and other animals to visit the flowers, and those plants gained a competitive advantage over the plants that relied on wind and water pollination.

flower parts

diagram of flower parts

Not long after the evolution of the first flowers, during a period called the Cretaceous, angiosperms started to diversify rapidly, so much so, that they quickly became the most species-rich group of plants on the planet. Today, there are over 300,000 species of flowering plants, which constitute about 90% of the species of plants on Earth. Likewise, insects and other pollinating animals underwent a period of rapid speciation. Coevolution between flowers and pollinators has resulted in the dazzling assortment of flower shapes, colors and smells that we see today and an amazing array of specialized adaptations among the pollinators. Diversification also has occurred among several groups of vertebrates that visit flowers. Mammals, birds, and reptiles that feed on flower nectar also coevolved with plants.

The selective force driving flower-pollinator diversification is a concept called "pollinator fidelity".Pollinator fidelity is a measure of how likely a pollinator will visit flowers of the same species of plants. Plants with adaptations that enhance pollinator fidelity are more likely to have their pollen delivered to the correct species of flower than plants that cannot ensure fidelity. Some plants ensure pollinator fidelity by specializing their flowers to serve a small set of pollinator species. Other flowers are more general but use other strategies to ensure pollinator fidelity This leads to the development of "pollination syndromes", the coupling of certain flower adaptations with particular pollinator behaviors.

Pollinator Syndromes

  • Tubular flowers, especially red ones, tend to be pollinated by hummingbirds. Their anthers and pistils are situated to contact the head feathers of the bird which prevents most insects from pollinating them. One dramatic example of hummingbird specialization is displayed by Heliconia tortuosa, a common forest flower in Central America. It is pollinated by only two species of hummingbirds (the Green Hermit and Violet Sabrewing) which have specialized bills. Although other hummingbirds will visit this particular Heliconia, the plant only responds when visited by one of these two hummingbirds because they are the only species with bills that can access the nectaries.
  • Some orchids perform sexual deception to get pollinated. Their flowers deceive male wasps by mimicking the shape, color and smell (pheromones) of female wasps. The male wasp pollinates the flower by trying to mate with it. This type of pollination leads to highly specialized flowers and is one of the many reasons that orchids are the most diverse family of plants.
  • Other plants with smaller, more generalized flowers ensure pollinator fidelity by synchronizing their flowering or producing large composite flowers. Increasing the abundance of flowers of a particular species increases the likelihood that pollinators will visit related flowers just by shear statistics. Many of these plants (like Asteraceae and Apiaceae) display their flowers prominently on the tops of the plants to make them highly visible.
  • Some plants produce large volumes of nectar to attract pollinators like honeybees and other social insects which are extremely efficient at locating the most productive flowers. Many social bees, especially honeybees and bumblebees are able to communicate the location of these nectar sources to their nest mates.
  • Some flowers limit which pollinators can access the reproductive parts by mechanical means. Nightshades have pollen that is trapped deep in the flower and can only be released by insects that can vibrate the flower vigorously, such as bumblebees, a phenomena called "buzz pollination." Flowers like the white turtlehead (Chelone glabra) remain closed and can only be accessed by the strongest of insect pollinators such as the carpenter bees.
  • Other flowers are extremely fragrant to attract particular insects from long distances. The earliest insect pollinated plants, the ancestors of today’s magnolias and waterlilies produced large sticky-sweet smelling flowers to attract beetles that feed on fermenting and decaying plant matter. Many of the Cactus which are pollinated by bats or moths at night produce very aromatic flowers. Taking smell to the other extreme, corpse flowers emit the odor of rotting flesh to attract flies and beetles that consume dead animals.

Evolution of flowering plants has led to adaptations that exploit a wide range of animal behaviors. In turn, the pollinators have responded by developing specialized relationships with particular groups of plants, and pollinator fidelity has created reproductive isolation that drives speciation.

Pollinator Conservation

Pollinator conservation is absolutely critical to biodiversity on Earth and ecological function in most terrestrial ecosystems. Because most species of plants have a mutually beneficial relationship with their pollinators, survival of one depends on the other. Plants are the primary food sources for most ecosystems. They support insects and wildlife that feed on them and shelter in their cover. They form the organics that support soil microbes and invertebrates that consume the decaying vegetation and build living soil for other plants to use. Plants alter microclimates and affect hydrology. Pollinators are food for an array of predators some of which actually seek particular insects to eat and plants to patrol. Also, many pollinators are predators or parasites of other insects, keeping pest populations in check. The decline of pollinators or their host plants would cause broad reaching changes to ecosystems, degrading conditions and negatively impacting species throughout the system. So, it is critical that humans account for pollinators and their host plants when altering land uses and vegetative cover.

The Importance Of European Honey Bees

No other insect has achieved the popularity of the honey bee. In fact, there are few other animals that have had as great an impact on human civilization as honey bees. Much is owed to these industrious insects which have shaped modern agriculture and human culture.

Intro to Honey Bees

The Western Honey Bee (Apis mellifera L.), commonly called the European Honey Bee, is one of the first animals cultivated by humans. Humans first learned to rob from wild colonies but eventually learned to carefully collect and care for honey bee colonies. For thousands of years, humans and honey bees have been mutually entwined to the benefit of both species. Before widespread cultivation of sugar cane, honey was one of the most widely available source of sugar to developing communities, and beeswax candles were a primary source of light for western civilizations before gas lanterns and electric lights. Beeswax also has been used in preserving and packaging a variety of materials. Some ancient cultures considered honey bees to be sacred, and catholic cathedrals usually kept honey bee colonies to supply candles for worship and sweetener to the community. honey has long been used for medicinal purposes, and it was the necessary ingredient in making mead, which was often the only alcoholic libation available. Honey bees have benefitted from humans as well. Humans have spread honey bees wherever they have settled, and the adaptable honey bee has been able to naturalize and establish wild colonies on every continent except Antarctica.

Benefits of Honey Bees

Honey bees produce tangible goods such as honey, wax, and propolis. The U.S. honey crop is valued at over $300 million annually (USDA Honey Report, 2019), and wax and propolis are used in an array of home goods such as candles, cosmetics, and health products, the total impact of which is not measured. The greatest economic impact of honey bees is through pollination of agricultural crops. Production of about one third of the human diet requires insect pollination, and honey bees perform the majority of pollination for these cultivated crops. Globally, three out of four species of cultivated crops are animal pollinated, and honey bees are able to pollinate most of these crops. In the United States, honey bees contribute an estimated $20 billion to the value of U.S. crop production annually. Some crops such as almonds, blueberries, and cherries rely almost entirely on honey bee pollination. By enabling the production of such an array of crops, honey bees have diversified the human diet, which provides high quality nutrition that promotes human health and longevity. Honey bees also contribute to livestock production through pollination of forage plants such as alfalfa and clover. Wildlife benefit from honey bees through the pollination of many wildland plants and as food to a large number of insectivorous predators. 

Honey Bees Influence on Human Culture

Honey bees influence human culture in many unexpected ways. Most languages have honey bee colloquialisms such as "busy as a bee" or "the bee's knees." Bees are the subject of art, old and new, adorning cave walls from over 7,000 years ago and in impressive works of the Renaissance like the massive Baldacchino that stands over the papal alter in St. Peter's cathedral in Rome. Honey bees have inspired music and song lyrics across many genres and are the subjects of festivals and celebrations across the globe. Honey's medicinal properties make it integral to spiritual ceremonies for cultures worldwide, and honey bees themselves are used as healing agents treating human ailments through Apitherapy. Honey bees even have been used as tools of war, deployed to attack the enemy, thwarting invasions and defending ancient cities.

So important are honey bees to humans that news of honey bee losses has made international headlines, raising global concerns about environmental sustainability. As a result, conservation of this species and other pollinators has become a priority for human civilizations worldwide.

The Clemson Apiculture and Pollinator Program was developed to provide an educational platform for beekeepers to help them maintain healthy stocks of honey bees in South Carolina, because the goods and services that honey bees provide to citizens of this state are critical. The program also was formed to increase awareness about the importance of native pollinators and protecting invertebrate biodiversity as a function of maintaining productive ecosystems and vibrant communities.