Up to 80% of all plant species are pollinated mostly by insects. Crucially, three quarters of the world’s most common human food crops require insect pollination. No small task for the marquee pollinators: bees and butterflies. Thankfully, they have help. Enter the fly and the wasp, less famous pollinators but doing a yeoman’s share of the work. Time to learn more about these underrated pollinators.
Flies
Did you know that, after bees, flies are the most important pollinators? That’s what the January 2020 study “Non-Bee Insects as Visitors and Pollinators of Crops: Biology, Ecology, and Management” found. While hundreds of fly species visit crops, hoverflies and blowflies lead the pollinator pack (or swarm as the case may be). As described in Smithsonian Magazine’s “How Much Do Flies Help with Pollination”:
“Hoverflies and blowflies visit flowers to drink nectar, which fuels energetic activities like flying, and eat pollen to get the nutrients needed for sexual maturation. Like bees, many of these flies are hairy and trap pollen on the head and thorax as they feed. Larger flies can collect — and carry — hundreds and sometimes thousands of pollen grains as they fly from flower to flower. Unlike bees, which must forage close to their hive or nest, flies don’t have to provide for their young and can roam more widely.”
Mango growers in Australia even use rotting flesh (from fish to roadkill) to lure blowflies to help pollinate orchards. If you’re not impressed by mango pollination, but you do love chocolate, then this may get your attention: flies are the only pollinators of the cacao (cocoa) tree. No flies, no chocolate. Keep that in mind the next time you sink your teeth into a gooey, fudgy brownie. But what about flies on this side of the world? Not many mango or cacao growers in Texas. What do flies help pollinate in the Lone Star State? In the Texas Hill Country, evergreen sumacs, for one, depend quite a bit on flies for pollination. Flies are also key flower pollinators, but they have a certain type. As described by the Texas Wildlife Association in Critter Connections:
“Flies are attracted to things that smell bad like garbage and dead animals, so fly-pollinated flowers produce a bad odor like rotting meat. The flowers are plain in color like meat, or darker shades like brown and purple. Fly-pollinated flowers are shaped like a funnel and sometimes act as a trap to catch the insect. Another interesting thing about fly-pollinated flowers is that many of them do not produce nectar. Flies enter the flower because they are attracted to the smell, picking up pollen along the way and once they realize there is nothing to eat inside, they move on.”
If you didn’t realize flies were out there working so hard that may be because their disguise has worked. As described in Science Friday’s “The Unexpected Pollinator of the Cocoa Tree”:
“Most people have no idea that most of the little yellow-and-black insects zipping round their garden at speed—some can fly in short bursts at up to 25 mph (40 kph)—are not the helpful bees they think they are, but rather helpful flies.”
One way to quickly distinguish between these two petite pollinators (assuming they stop zipping around for a moment) is flies have only one pair of wings while bees have two pairs.
Wasps
If you’ve been stung by a wasp, it’s hard to imagine ever seeing them as anything other than little flying devils—hovering around your back door, trying to make a nest, just biding their time until they can sting you again. But, if you can, put understandable grudges aside and consider the wasp as helpful pollinator. Indeed, the first bees evolved from wasps. In its ode to the wasp, “Wasps Are the Bees Knees,” Popular Science addresses this “forgotten cousin” of the bee family tree:
“Bees have whole societies devoted to their conservation, while wasps, if thought of at all, pile up in yellowjacket traps…(but)…As it happens, stinging wasps also pollinate, if only by accident. Since the adults live mostly on sugar, they visit flowers to collect nectar, moving pollen around on the way.”
Despite their sleek killer appearance, and although admittedly not as hairy as their charming bee cousins, wasps do have fine, virtually invisible hair on their bodies to which pollen can cling. When it comes to pollinating, wasps are “generalists” that will pollinate just about any flower unlike bees that have been described as “quite fussy” when it comes to the types of flowers they’ll pollinate. And while, generally, wasps are pollinating generalists, some do have a specific purpose—pollinating figs—and it’s a heck of a purpose.
Briefly put, when a tiny fig wasp finds a fig with flowers, she shimmies through a small opening, often tearing off her wings and antennae in the process. Now, flightless and stuck inside, she lays her eggs and then dies. When the eggs hatch, they mate with other wasps born in the same fig. After mating, the males dig a path out for the females so they can find new figs. The wingless males then die inside the fig. For more details on this figgy miracle of nature, check out “So, Uh, There are Wasps in Figs?!”
Ever heard what they say about squirrels? They’re just rats with bushy tails and good PR. Similar might be said about wasps. In “Wasps Have an Image Problem, But Here’s Why We Need Them” pulls no punches: “Who wants to fund a nasty wasp study, after all, when we can publish the one-trillionth paper on the beauty of bees?” In the article, Seirian Sumner, Ph.D., who studies the evolution of insect social behavior at the Center for Biodiversity and Environment Research at University College London addresses the bias against wasps:
“The reason we hate wasps culturally is because we don’t understand what they do,” says Sumner. “And the reason we don’t understand what they do is because there’s very little science to show what they do. If we can make people think about wasps the same way they think about bees, then we can turn the wheels around and change the public perception of wasps.”
Will an impassioned Dr. Sumner and a Christmas figgy pudding make you feel differently about wasps? Possibly not. But if the next time you take aim to swat a wasp and miss, a flower may be pollinated.
Photo above of wasp and bee by James Wainscoat on Unsplash
