The Science of Sustainability

Meet the Natives: Wild Bees

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Before I met Claudio Gratton, an entomologist at the University of Wisconsin-Madison, my idea of a “bee” was a little striped insect that lives in a hive and makes honey, pollinating the flowers whose nectar it collects.

But according to Gratton, the honeybee that I’m imagining is only one of a huge, diverse — and largely unknown — set of bee species on the planet. Despite their ubiquity in North America, honeybees are a European import.

“There’s a lot of other pollinators out there,” explains Gratton. The 500 or 600 wild bee species that live in Wisconsin are only a fraction of the 4,000 native to the United States. But because they tend to be solitary, aren’t easily managed, and don’t produce honey, they’ve mostly flown under the radar.

I saw some of these native bees neatly pinned in glass cases in Gratton’s lab. They range from big, fluffy bumblebees to tiny creatures barely larger than the head of the pin skewering them. Some are iridescent — almost otherworldly.

Augochlorella aurata, one of the four thousand bee species native to the United States. Image by Sam Droege, USGS Native Bee Inventory and Monitoring Program.

Augochlorella aurata, one of the four thousand bee species native to the United States. Image by Sam Droege, USGS Native Bee Inventory and Monitoring Program.

Much more than just eye-catching novelties, native bees could be the key to avoiding an impending agricultural crisis.

We rely on honeybees to pollinate about three-quarters of the world’s food. Crops like almonds, apples, onions, and blueberries all need animals like insects and bats to ferry pollen from anther to stigma. Most commercial farmers rent honeybee hives each year to provide pollination services. But over the last decade the honeybee population has been devastated by an onslaught of agricultural chemicals, diseases, parasites, and climate-change-induced shifts in plant behavior. In combination, these forces cause Colony Collapse Disorder, which has claimed a third of the nation’s honeybees every year for the last seven years.

Could wild, native bees step into the breach and offer the same agricultural support long provided by honeybees?

“Using native pollinators as a substitute for honeybees is something we’re looking at,” Gratton says. After all, before European settlers arrived with their straw beehives in the 17th century, wild bees and other native pollinators turned America’s flowers into food. Based on Gratton’s studies of cranberry farms in Wisconsin (the country’s largest cranberry producer), they may be doing it again. Some cranberry farmers can get a good yield without bringing in any honeybees at all. A study in New Jersey found similar results for watermelons. In fact, some recent data suggest that wild bees may be even more efficient pollinators than honeybees.

So how can farmers encourage wild bees to pollinate crops? Studies suggest that strategies like planting small patches of other flowering plants among crops, avoiding pesticides and herbicides, and planning crop rotations to ensure blossoms throughout the season can all encourage native-pollinator activity. But perhaps most critical, says Gratton, is keeping agricultural landscapes diverse. Because wild bees depend on natural landscapes for habitat and food, interspersing fields with uncultivated areas like grasslands and forests can actually increase crop yield.

Native bees, like these bumblebees visiting flowers in the University of Wisconsin Arboretum, may be able to replace some of the agricultural pollination services provided by honeybees, which are currently struggling.

Native bees, like these bumblebees visiting flowers in the University of Wisconsin Arboretum, may be able to replace some of the agricultural pollination services provided by honeybees, which are currently struggling.

As Gratton points out, “We often think of these areas as wastelands, as unproductive environments, when in fact they’re very productive.”

But even if farmers are able to attract native bees, one of the key questions is whether or not these bees will be able to sidestep the challenges facing honeybees.

The answer is “maybe.” In honeybee colonies, tens of thousands of bees pick up an array of pesticides and herbicides as the hives are trucked around the country chasing blooming crops. These chemicals get commingled and concentrated in the food fed to the queen bee and her young. This can create a toxic cocktail that wipes out generations of larvae. But most native bees tend to be loners. A single bee feeding only her own offspring might be able to avoid the disastrous effects of concentrating and combining agricultural chemicals.

But these are new questions, and the answers won’t reveal themselves without much more data, which can be difficult for researchers to collect. Wild bees’ solitary habits make them especially challenging to study.

“One of the things I would love to do,” says Gratton, “is to have eyes everywhere in the landscape.” But even if you can find them, bee species are tricky to tell apart — even for experts — so Gratton is working with colleagues in the engineering department to develop a computer program that can identify a bee’s species just by looking at the veins on its wings. He’s hoping that one day this technology will become a mobile app, so anyone anywhere could snap a cell phone picture and help entomologists like Gratton make sure that native pollinators keep on pollinating.

For now, Gratton and his students troop into the landscape with low-tech equipment, trapping bees with insect nets, bowls of soapy water, and simulated nests made out of bamboo. They painstakingly catalog the insects they catch. And they hope that the data they collect will shed light on the promise that native pollinators can help build sustainable agricultural systems — with or without honeybees.

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Category: Biodiversity, Climate, Environment, Video

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Eleanor Nelsen

About the Author ()

Eleanor Nelsen is a graduate student in chemistry at the University of Wisconsin-Madison. When she's not studying rhodium chemistry, Eleanor enjoys reading and writing about science. She lives in Madison with her husband Luke and their growing collection of livestock.
  • Lindsey Hoshaw

    I had no idea there are so many different types of bees. There are 4,000 that are native to the US?! I have a vivid memory of stepping out on my back porch in Arizona as a kid and watching something drip from the roof. It was honey and my family discovered that local bees had built a hive in the walls and in our roof. There was nothing quite so joyous as tasting fresh honey made (literally) in my own backyard.

  • http://www.facebook.com/wesley.rolley Wesley Rolley

    This is a good article about a real problem. We are in the Santa Clara Valley with a lot of fruit trees, all pollinated by native bees and never have a problem. The only thing missing from the story is that much of the honey you can buy in big box stores comes from factories in China, manufactured by people, not bees.

  • Eleanor Nelsen

    Lindsey — I know, I was amazed by how many species there are, too! Ever since we interviewed him, I've been on the lookout for unusual bees. And what a cool story about the honey dripping off the roof…I'm curious about what happened to the beehive, though!

    Wesley — thanks for your comment! It's great to hear about areas that are bucking the conventional wisdom that honeybees are indispensable. And there are so many aspects of pollinator ecology and honey (or "honey") production that need (and fortunately are now getting!) media attention, cheap foreign honey among them. Yet another reason to support your local farmers' market!

  • roxanne fox

    i have been harboring bees now for 15 years where i live on a restore the wetlands project in northern louisiana. i am organic as of 8+ years. the gas drilling and fracking here is awful, air emissions coat the leaves and flowers with trace chems that drop the bees dead. i have a bamboo stand and make bee homes. i have well water for misting they love. many diversified bees live happily together, i have plants from everywhere i transplant to my yard of 3 acres from the 7,000 down in the duck ponds area. this land piece is the only one NOT leased and drilled on. it is daunting to pick up dozens of dead bees around these drilling sites., evidence of the toxins emitted., on just a one day walk. i also habitat for tree frogs, dragonflies and butterflies. the bees, i am passionate about. i'm known as the crazy bee lover who refuses to mow or bushhog leeways! my signs declare:
    "Don't Tread on Me,. Bees". i also put rinds and fruit out and often see bees on these feeding that i otherwise see only on certain plants. they are adapting to the hard times of cleared plants needed to sustain them. i have bees yearround. but then i do envite them.

  • http://www.unctv.org David Huppert

    love that bee-net!

  • Ana Miguel

    I wish all lovely and care for you 2 and iam thankfull for all you been doing to ours planet earth (home) living all together http://www.adobedesigner.com visit my website all greetting from Ana.

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