Spring has not been canceled! While humans are social distancing and burrowed in at home, the earth is still spinning, the days lengthening, and weather restlessly churning out showers, winds, and sunshine to boost springtime growth before the parched summer months. Like us, plants seem keen on the changing season, bursting forth a palette of hues seemingly for our rapt enjoyment. But, alas, the end goal of flamboyant flowers is pollination and reproduction for its species, not brightening our neighborhood walks or perching elegantly in a vase.
Pollinators are crucial to our food supply—over 150 edible crops in the US depend on pollinators, including those favorites, apples, oranges, and tomatoes, and countless other foods. As most plants are rooted in one place, they evolved a type of quid pro quo for getting their pollen grains moved from the flower’s male parts (called anthers), to the female parts (the stigma). Many plants create delicious, high-energy nectar for creatures that swoop by for a snack then move to another flower, transferring pollen in the process. Types of pollinators are as varied as the plants they are attracted to.
Pollinators include scores of flying animals, so having brightly colored flowers can be a good way to attract attention. “Worldwide, there are more than 100,000 different animal species that pollinate plants,” according to the U.S. Fish and Wildlife Service. “Insects are the most common pollinators, but as many as 1,500 species of vertebrates also help pollinate plants.” Of course, a flower's shape, scent, and color conspire to serve its favorite pollinators. For instance, tubular-shaped flowers that are scarlet, orange, or white and mostly scentless are a big hit with hummingbirds sporting straw-like beaks and the ability to hover in front of a flower before moving to the next.
Perhaps the best known pollinator is the mighty bee. Nothing bumbling about these intrepid little explorers! With around 20,000 known bee species, they are found in every habitat on the planet that has insect-pollinated flowering plants. The US has over 4,000 native bee species. Not all bees “dance” or live in hives. In fact, the majority of bees are solitary, but bumblebees and honeybees are highly social, living in organized nests or hives. About 70 percent of bee species nest underground in tunnels in sand or take shelter in abandoned beetle burrows. But they do love brightly colored flowers that are open during the day with a sweet or minty scent. The flower must provide a “landing platform” so the bee can perch as it takes on nectar and pollen. You can plant a bee-friendly garden with native plants for your region, and resist using pesticides, to keep your bees busy and thriving!
Though they may be the bane of your barbecue, flies also pollinate plants. Not surprisingly, they are drawn to foul-smelling flowers that are pale, dull, and dark brown or purple. While not as hairy as bees, and thus less efficient pollinators, these two-winged insects (which include flies, gnats, and mosquitoes) swoop in for nectar, which can be risky if they choose a plant designed for a different pollinator. For instance, the U.S. Forest Service describes how dogbane, a shrubby herb that flowers in July and August, attracts butterflies whose long tongues become coated with pollen and a cement-like mixture from the flower. Butterflies can still lift off with the “load” but weaker pollinators like flies remain glued the flower and perish in a cloud of pollen.
One of the most important food groups relies on a tiny type of fly, the midge, for pollination. Chocolate comes from cocoa trees that flourish in the tropics. Its small, white flowers grow along the trunk and low branches. Unusual among flowers, they face downward and smell vaguely like mushrooms, which invites the miniscule midge to carry out its important chocolate-coated duties.
Plenty of mammals get in on the pollination action, too. Nectar-feeding bats are drawn to large, fragrant flowers that open at night and are pale in color. Other types of bats feed on the insects in the flowers, and collect pollen morsels in the process, thereby also serving as pollinators. Over 300 species of fruit are pollinated by bats, including mangoes and bananas. Jose Cuervo and other tequilas can also thank bats for their product, as agave plants rely on these nocturnal pollinators. The fancy word for the pollination of plants by bats is called chiropterophily.
The largest pollinator is the black and white ruffed lemur of Madagascar, whose strength and dexterity is needed to pollinate the traveler’s palm, an important edible fruit on the island. The lemurs climb high in the tree and use their nimble fingers to pry open the tough flower bracts, and poke their muzzle and tongue inside, collecting pollen in their fur and traveling to the next flower to spread the joy. There are scores of willing and unwitting pollinators around the world, which flowers cater to with their color, scent, and structure. Planting and nurturing gardens with this in mind will support life cycles of springtime and beyond. And brighten up our world.
Karyl Carmignani is a staff writer for San Diego Zoo Global. Read her previous blog, Watch Your Ps and Qs...Animal Style.
