Pollination is how plants create the next generation their species oftentimes with the help of pollinators. More accurately, it’s the process required to allow plants to become fertilized and develop seeds. Did you know that a flower has both male and female reproductive parts? The male part is called the anther, which is the part of the flower’s stamen and the location where pollen is produced. At its very core, pollen is actually a substance made up of microscopic grains containing male gametes, or sperm cells. The female part of the flower is located on the pistil of the flower, and it’s where pollen germinates.
Pollination is what happens when pollen from the anthers of a flower is transferred to the stigma of another (or sometimes the same) flower. After this union, fertilization can occur and the flower will develop seeds. The seed of a plant is basically an embryo with the potential for developing into a brand new plant – behold the reproduction process of plants!
Pollination can occur from more than one method, and some flowers can even self-pollinate within the same plant. However, for many plant species, pollination must occur between different plants and therefore require a medium of pollen transport. The wind or flow of water can be helpful for many plants, but it’s not always very reliable and wind or water have no incentive to consistently visit flowers. This is why animal pollinators such as bees, butterflies, beetles, moths, bats, birds, and other species are fantastic pollen movers.
For pollinators and pollinator-dependent plants, the relationship is a two-way street. Pollen provides a good source of protein for species such as honeybees, while the nectar produced by the flowers of the plant are a great source of carbohydrates for many animals (not to mention a sweet snack!). In exchange for providing these important nutrients, the animals help distribute the plant’s pollen and aid in reproduction and population growth. Pollination by animals can also promote plant diversity, which is great for adding genetic strength and resilience.
As you can imagine, plants need a lot of those pollinators to be available to them. Furthermore, there are a LOT of plants that require animals and insects (such as honey bees)to help them pollinate. In fact, researchers have estimated that upwards of 87.5% of all flowering plants, or angiosperms, are animal pollinated (Ollerton et al. 2011). This is a huge number of plants that require bees, birds, and other species in order to fertilize and reproduce. Some pollinators are specialists that have adapted to a select few types of flowers, while others are generalists and don’t really care what types of flowers they use.
There are hundreds of species of pollinators; according to the USDA Plants Database, there are about 200,000 different kinds of animals that act as pollinators! Each species has their own unique behaviors and methods of foraging and pollination. (Note: A few less-known pollinators not mentioned here include monkeys, rodents, lizards, and even some large carnivores such as bears and coyotes. The need for more research on all types of animal pollinators is crucial to improving our understanding of ecosystem-level plant and animal connections).
Bugs are truly amazing little creatures! They can do so much for ecosystems and agriculture, and yet they are often underrated. Many species of bees, including honey bees, leafcutter bees, mason bees, bumblebees and other wild bees are all excellent pollinators for a massive variety of crops that we use on a daily basis. In fact, approximately $14 billion worth of crops are pollinated by honey bees each year, according to the American Beekeeping Federation. Bees are often referred to as “super pollinators” due to their wide range of target plants and significance in pollinating agricultural crops. While bees visit flowers to forage on their pollen and nectar, pollen becomes attached to them and gets dropped onto new flowers at each visit.
Aside from bees, many native insects such as butterflies, flies, beetles, and moths all play important roles in pollinating crops and flowers. Butterflies are especially known for their visits to a variety of wildflowers. Many insects also represent cultural symbolism in many indigenous cultures.
Important crops that insects help pollinate: alfalfa, almonds, anise, apples, apricots, avocados, blueberries, cardamom, cashews, cherries, chocolate, coffee, coriander, cranberry, grapes, grapefruit, kiwifruit, macadamia nut, mangos, melons, nutmeg, papaya, peaches, pears, peppermint, pumpkins, raspberries, blackberries, sesame, strawberries, sugarcane, tea plants, tomatoes, and vanilla. It’s also extremely important to note that alfalfa, which is pollinated by leafcutter and honey bees, is a huge source of food for livestock such as dairy cows.
Although birds are not specialized in pollinating food crop plants like bees are, they still play highly important roles in the pollination and seed distribution of plants and flowers around the world. According to the United States Department of Agriculture, there are approximately 2,000 species of birds globally that feed on nectar. Some of the most common bird pollinators are hummingbirds, honeyeaters, and sunbirds. Due to their keen eyesight, birds are generally attracted to bright, colorful flowers that produce large amounts of nectar. Many plants have adapted to attracting and utilizing the bird’s mobility by being especially flashy, full of nectar, and producing larger sized pollen that will stick to bird feathers more easily. Many nectar-feeding birds have evolved to have longer, slimmer beaks that are more ideal for retrieving nectar.
Important crops that birds help pollinate: Bananas, nutmeg, and hundreds of plants and flowers that are significant for wildlife habitat, gardens, and more. Birds are also great at dispersing seeds, enhancing forest growth, and controlling pests.
Bats as pollinators do not get a lot of spotlight, but they are actually very important contributors to the pollination of several popular crops as well as flowers and other plant species. According to the Bat Conservation Trust, bats are vitally important pollinators for many plant species; in fact, there are over 500 species of plants that rely on bats for pollination. Bats are nocturnal flying mammals that often get a bad rap, but they are actually interesting and unique pollinators deserving of respect and conservation.
Important crops that bats help pollinate: avocados, cashews, coconuts, agave (tequila), mangoes, cocoa, durian, and guava. Many native plants and flowers that we use for medicinal, cultural, and economic purposes rely on bats for pollination. Bats are also amazing pest controllers – which is great form of natural agricultural pest management.
Have you enjoyed a fresh fruit or a delectable piece of chocolate lately? Did you devour a hot cup of coffee this morning? Have you enjoyed walking through a field or garden of flowers while immersing yourself in their sweet, fresh scents? These are just a few of the hundreds of things that we wouldn’t get to enjoy without the help of pollinators. Pollinator species, which range from tiny honey bees to large, fruit-eating bats, are the ones to thank for many of the foods, drinks, products, and outdoor pleasures that are available to us every day.
Aside from providing us with at least 75% of the food we consume, pollinators are also key ecosystem providers. Plants and wildflowers are vital components of ecosystems, and they require pollination to propagate and disperse across their environments while maintaining genetic diversity. Flowering plants provide cleaner air through photosynthesis, add stability to soils, purify water, and provide a source of food and habitat for wildlife. Pollinators are also great ecosystem indicators, meaning that we can study them to learn more about the condition of ecosystems, including the stress and health of the environment and changes in species diversity and abundance (Kevan 1999).
These creatures are often small in size, but they play absolutely gigantic roles in agriculture, ecosystem services, and biodiversity on our planet. Without them, life would not be the same, and we would be looking at a very bleak planet. If pollinators are to continue enriching our lives, ecosystems and environments, they will require our help both now and in the future.
Pollinator species across the globe, including both wild and domesticated populations, have faced many challenges and declines in number and abundance for the past several years (Potts et al. 2010). The loss of pollinators equates to negative effects on flowering plants, causing further damaging economic and ecological impacts around the world. This is more than just a human welfare or population-level issue – the loss of pollinators has profound implications on a global scale. There are five primary threats to pollinator species, and it’s important to note that the depth and complexity of these threats are far-reaching and dynamic in many ways that we may not yet understand.
Habitat loss. With the expansion of industrial agriculture and human development, many habitats have shrunk, fragmented, or disappeared completely. This includes natural spaces containing important forage and nesting sites for wildlife species, including pollinators such as birds and bees. Studies have shown that declines in pollinator abundance align with increasing habitat fragmentation (Rathche and Jules 1993).
Climate change. Changing climate conditions have caused mass movements of temperature gradients, causing flowering plants to grow farther north and leave behind their pollinators. Although many pollinator species such as bees are very adaptive, changing distributions of pollinators and flowering plants have been causing a displacement in ecosystem dynamics.
Pesticides. Pesticides are used to deter and kill unwanted pests and weeds for crops and flowers. However, they often end up destroying non-target species such as honey bees. The use of harmful pesticides and other anthropogenic pressures are one of the leading causes of pollinator declines and losses (Vanbergen 2013).
Invasive species. When humans bring new species into a novel environment, they may have a competitive edge over the native species and begin to overtake niches (the position of a species in an ecosystem). This can result in high levels of competition and predation for native species, including pollinators.
Diseases and parasites. A combination of the above factors can lead to the increased spread of non-native parasites and diseases. In the case of honeybees and other native bee species, parasites such as varrora mites have caused the collapse of colonies and population bottlenecks.
Although the situation is desperate, there is a lot of actions we can take to save pollinator species while dueling working to solve our own agricultural and environmental problems, including food shortages, crop disease, habitat loss and fragmentation, water purity, and much more.
Stabilizing and restoring pollinator species and flowering plant populations will not happen overnight. It will require a great deal of effort on our part, with consistent and adaptive actions and research. The simple truth is that we need pollinators, and pollinators need us. Considering the endless ecosystem and agricultural services and products that pollinators provide for us, it is our responsibility to ensure that pollinators, such as bees, birds, and bats are here to stay and flourish for future generations.
Kathleen, GC (2010). Diet and reproduction of sympatric nectar-feeding bat species (Chiroptera: Phyllostomidae) in French Guiana. Columbia University, 229 pages.
Kevan, PG (1999). Pollinators as bioindicators of the state of the environment: species, activity and diversity. Agriculture, Ecosystems and Environment 71:473-393.
Ollerton, J, Winfree R, and Tarrant SP (2011). How many flowering plants are pollinated by animals? Oikos 120:321-326.
Potts SG, Biesmeijer JC, Kremen C, Neumann P, Schweiger O, and Kunin WE (2010). Global pollinator declines: trends, impacts and drivers. Trends in Ecology and Evolution 25:345-353.
Ratchscke BJ, and Jules ES (1993). Habitat fragmentation and plant-pollinator interactions. Current Science 65:273-277.
Vanbergen AJ (2013). Threats to an ecosystem service: pressures on pollinators. Frontiers in Ecology and the Environment 11:251-259.