The Pollinating Power of Bumble Bees

Mar 10, 2022

By Molly Jameson

There are five social species of bumble bees (Bombus spp.) native to Florida, and each is an important pollinator throughout the state. European honeybees provide about 85 percent of our pollinating activity that is vital for supplying one-quarter to one-third of our food supply. Bumble bees, however, are also very important for pollination. More well known for their ability to pollinate native and ornamental plants, they can also pollinate a variety of food crops, including tomatoes, peppers, cucurbits, strawberries, blueberries, fruit trees, cover crops, and more.

pollinating

An American bumble bee pollinating white clover. Bumble bees are efficient pollinators of many crops and cover crops. Photo by B. Merle Shepard, Clemson University, Bugwood.org.

One way bumble bees outshine honeybees is in their ability to “sonicate” or “buzz pollinate” certain flowers, such as tomatoes, peppers, and blueberries. For instance, although tomatoes are self-pollinating (each flower contains both male and female plant parts), their flowers must be vibrated by wind or insect in order to release pollen for fertilization. When bumble bees land on a tomato flower and vibrate their bodies, it shakes pollen from the anther (the male part of a flower) to the stigma (the female part of the flower), resulting in pollination. Honeybees are not capable of vibrating at the frequency needed to open a tomato flower. Although wind also pollinates tomatoes, studies have shown that pollination by native bees can increase tomato fruit set by nearly 50 percent more than with wind alone! Additionally, native bees help cross-pollinate tomato plants, leading to larger tomatoes and an increased overall yield.

Another advantage bumble bees have over honeybees is in their pollination efficiency. For certain crops, such as strawberries, bumble bees are two-and-a-half times more efficient at pollination than honeybees. Some species of bumble bees also have a longer tongue than honeybees, which allows them to pollinate certain flowers, such as red clover, more effectively.

Here in our sub-tropical humid climate in North Florida, we experience many rainy and cloudy days throughout the year. On these days, honeybee foraging decreases significantly. Bumble bees, however, have larger bodies with more hairs that allow them to regulate their body temperatures more efficiently. This gives them the ability to forage for pollen and nectar on days honeybees are inactive.

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A diversity of native pollinator plants supports a diversity of native pollinators. Photo by Rachel Mathes.

Although it is very common for farmers to import honeybee colonies onto their farms to increase pollination rates, importing bumble bee colonies for open field crop pollination has had mixed results. Imported bumble bee colonies can, however, be very useful in closed settings, such as greenhouse tomato or cucurbit production. It may seem intimidating to work so closely to stinging insects, but bumble bee colony breeders select for mild-mannered bumble bees that pose little threat to greenhouse operators.

In open field settings, it is much more effective to harness the pollinating power of bumble bees by providing a diversity of nectar and pollen-rich plants to support wild bee colonies. Bumble bees are generalists, meaning they will visit a wide variety of flowers to suit their needs. Native plants provide the best sources of nutritious nectar and pollen for bumble bees and other native pollinators. Native wildflowers such as goldenrod, Coreopsis, Elliott’s aster, purple coneflower (Echinacea), thistle, Spanish needle, tickseed, swamp sunflower, dotted horsemint, and ironweed – among many others – are great nectar sources for native Florida bumble bee species. A few hedge rows, pollinator strips, or uncultivated farmland containing these plants can encourage bumble bees to inhabit the area. If purchasing a wildflower seed blend, be sure the mix is suitable for our area and does not contain invasive or weedy plant species.

Along with providing pollen-rich areas, it is also important to provide a place for queen bumble bees to nest. Nesting sites for bumble bee queens can be as simple as an old tree stump, a pile of leaves, or a hole dug by a larger animal. You can also install bumble bee nest boxes around the farm to encourage inhabitation. Lastly, help support pollinators by minimizing the use of insecticides – especially while flowers are present – and look for formulations that are least toxic to bees and other pollinators. By supporting pollinators and pollinator habitats, we also support our food supply, economy, and our environment.

Source : ufl.edu

Video: Can Gene Editing Give Seeds a Stronger Start?

Reagan Reed has a way of describing his research that might make a plant breeder pause.

“I’m the sort of person who likes to break things to understand them,” he says.

What he breaks are genes involved in seed germination. Reed, a Ph.D. candidate at the University of California, Davis, is investigating whether changing those genes can help seeds establish healthy plants under a wider range of conditions.

Reed recently attended the National Association for Plant Breeding meeting in College Station, Texas, as an NAPB Borlaug Scholar. His work speaks to a question that matters well beyond a research lab: what does it take for a seed to get a crop off to a strong start?

A seed that germinates quickly, alongside the others planted with it, spends less time vulnerable to stresses before seedlings become established.

“If you’re able to bridge that gap between germination to stand establishment, then that’s going to give you the highest probability of having a solid yield that year,” Reed says. “There’s a bunch that can go wrong after that, but it maximises your yield from the start, at least.”

Reed works in Dr. Imtiyaz Khanday’s lab at UC Davis, where his research focuses on seed quality in tomatoes and potatoes. He brings an unusual academic background to the work: at Skidmore College, he studied both biology and Latin.

Reed believes that combination prepared him for research. Translating an ancient text means studying each word, weighing its possible meanings and using context to reach the best interpretation. There is rarely a way to know with complete certainty what an author intended. Science, he says, requires a similar willingness to work through uncertainty.

“Attention to detail and comfortability working with uncertainty,” is how he sums up what Latin taught him.

In the lab, uncertainty can produce a surprise. Reed describes changing one gene and seeing little effect. Changing a second gene also appears to do little. Put both changes in the same genetic background, though, and the result can be substantial.

“I break this gene, nothing really happens. I break this other gene, nothing really happens. I combine them into the same genetic background, and now there’s a massive effect,” he says.

Those interactions matter as researchers gain the ability to edit multiple genes at once. They also complicate any simple account of how a trait works: improving a seed may depend on understanding what several genes do together.

For Reed, the question is whether that knowledge could help seeds germinate reliably when conditions are difficult. Some of the genes he studies prevent germination under certain conditions. That response may serve a plant well in one setting while limiting its usefulness in agriculture. He wants to learn what happens when those genes are changed, and whether the result improves establishment.

Yet a discovery that works in a lab still has a long way to travel before it reaches a field. Reed argues that agricultural biotechnology faces an economic challenge as well as a scientific one. New tools can create value for farmers, he says, but developing them requires a way to support the work in an industry where margins can be thin.

His fellowship with Flagship Pioneering gave him a view across AI, agriculture-related work and human health research. It also reinforced the importance of bringing people with different expertise into the same conversation—a benefit of gatherings such as the NAPB meeting.

“You need to have a team of people with different backgrounds who are willing to work together and approach the same problem in different perspectives and different ways,” he says.

That thinking connects the different parts of Reed’s path. Latin taught him to examine details without expecting a perfect answer. Gene editing lets him test what individual genes do—and what happens when their effects combine. Working with people beyond his own field helps him ask what those findings could become.

He came to agriculture because of its reach: the possibility that work by a small group of researchers could eventually make a difference on a much larger scale. His immediate focus is smaller and more precise. He wants to understand what helps a seed get through its first days and become a healthy plant.