Stingless bees: Waiting for their moment in the sun
With stingers that are harmless to humans, stingless bees could be the pollinators that save the day.
Wed, Jul 09, 2014 at 02:03 PM
A stingless bee collects nectar. (Photo: Dr. Breno Freitas/Universidade Federal do Ceara in Fortaleza)
Just as a prudent financial investor needs a balanced stock portfolio in case one of the stocks starts underperforming, the world’s forests, fields, and farmers need a balanced pollinator portfolio in case a key pollinator becomes threatened or goes extinct.
The over-reliance of commercial agriculture on the honeybee, usually Apis mellifera, to pollinate crops worldwide and the honeybee’s recent global decline have created a perfect storm for that beleaguered insect, said Dr. Stephen Buchmann. An adjunct professor in entomology and ecology and evolutionary biology at the University of Arizona who specializes in insect/plant interactions, Buchmann believes an insect that many people in the United States have never heard of is waiting in the wings to help balance out the world’s pollinator portfolio. He is talking about stingless bees.
Stingless bees have been around for more than 90 million years, but many people in the U.S. may not have heard of them because they are not cold-tolerant and live only in the Old World and New World tropics in the Americas, Africa, Asia and Australia. They are called stingless because, even though they have stingers, their stingers are atrophied and harmless to humans.
A large and diverse group of bees in the tribe Meliponini, stingless bees comprise about 30 genera and 400-500 species. They range in size from those as small as tiny fruit flies, to ones the size of house flies, to those as large as bumble bees. While they lack the ability to sting, they defend themselves in a variety of other ways, including biting, pulling hair on the body, getting into eyes and ears, and spitting irritating acidic substances on intruders that cause painful burning sensations.
“People in the United States have no awareness of stingless bees even though they have 40 times more species than the honeybee (Apis),” said Buchmann. (Others put the rate as high as 50 times as many species.) “There are 11 species of Apis, but in the United States there is really only awareness of one of these species, Apis mellifera."
The worldwide decline of the honeybee has occurred in part, Buchmann said, because honeybees tend to be sickly. “They don’t have a lot of genes for genetic repair.” Their susceptibility to diseases and other problems has led him to another conclusion.
“I have seen the smoking gun with what is poisoning honeybees worldwide that has convinced me of the need to balance the pollinator portfolio with redundancy,” he said. Buchmann calls that smoking gun a class of synthetic insecticides used to treat seeds before they germinate. He contends the insecticide travels into plant tissues after the seeds sprout, gets into the pollen and nectar, and is picked up by honeybees when they visit the flowers.
These insecticides will affect stingless bees if they visit agricultural crops that have been treated with them, Buchmann said. But, he added, stingless bees are likely safer from insecticides than honey bees. That’s because the primary role of stingless bees, as it has been for centuries, is to pollinate forest trees, a task Buchmann calls critically important.
In the Yucatan, for instance, which Buchmann said is Mexico’s biggest honeybee-producing area and where he has researched stingless bees for 30-plus years, stingless bees and honeybees play different roles. “Stingless bees pollinate the tall forest trees,” Buchmann said. “Honeybees generally pollinate crops and weedy plants along roadsides.”
“Research into stingless bee use in agriculture is fairly new, although the use of stingless bees as crop pollinators is changing and becoming more widespread,” he added. “Many universities in southern Mexico and Brazil are researching the use of stingless bees, primarily species within the genera Melipona and Trigona, on crops as well as native plants.
Buchmann is one of a group of researchers in the U.S., Central and South America, Australia, Japan, and several countries in Europe who are studying stingless bees and trying to expand the historical pollination role of these bees into agriculture. While in ancient times stingless bees certainly helped to pollinate crops of civilizations such as the Mayans, the goal now is to explore their commercial agricultural potential to enhance global food production and distribution.
For his part, Buchmann has co-authored a brochure to help beekeepers and farmers in Yucatan maintain colonies of stingless bees, especially Melipona beecheii. The brochure has been translated into Spanish and Mayan and distributed during workshops given by Dr. Rogel Villanueva-Gutierrez (ECOSUR, the College of the Southern Frontier) in Chetumal, Quintana Roo, Mexico.
Stingless bees from Tetragonisca angustula are popular for beekeeping. (Photo: Demeter /Wikimedia Commons)
Dr. Breno Freitas, a professor at the Universidade Federal do Ceara in Fortaleza, Brazil, is another researcher who has conducted numerous studies of stingless bees. He also believes they are a promising group of pollinators and have the potential to help farmers around the world reduce over-dependence on the honeybee.
To understand stingless bees, though, he said they must not be thought of in terms of the honeybee and a single, signature species but as group of species with no keystone species among them. “Some show more potential to be domesticated and managed as a crop pollinator,” he said. “Others can still contribute to crop pollination, but the grower has to conserve the natural environment around the plantation to attract these species.”
Also, he added, stingless bees are generalists. “Therefore, one cannot find a crop or wild species dependent on a particular stingless bee species. Their importance resides exactly in the fact that they pollinate a range of native plant species and can potentially be used in a diversity of crop species.”
His research has shown some good examples of the potential for stingless bee use in commercial agriculture. As an example, Dr. Freitas said that some years ago his group tested the stingless bee Melipona subnitida for the pollination of greenhouse sweet peppers. “Although fruit set did not differ from the bee-pollinated to the self-pollinated flowers, M. subnitida significantly increased fruit weight (by 30 percent) and the number of seeds per fruit (by 86 percent) compared to the control. Also, the bee pollination resulted in significantly less deformed fruits compared to the control (65 percent decrease)."
“Although stingless bees certainly contribute to the pollination of many crops in the third world, those contributions have not been quantified,” he said. "Their present role in crop pollination is difficult to assess because it is limited to wild colonies visiting crops in developing countries. However, as the research into breeding and managing these bees for pollination purposes increases, along with the decline of the honey bee, I am sure they will grow a lot in importance not only in the tropics but also in greenhouse crops in the temperate world.”
Some studies and trial runs have been conducted on a small scale, he said. Germany and Japan – two countries where stingless bees do not occur naturally – are successfully experimenting with stingless bees as pollinators in protected environments, which is one of Dr. Freitas’s research lines. “Due to the reduced number of individuals per colony, limited flight range, and the fact that they do not sting, I believe stingless bees fit enclosure pollination better than other bee species and better than they would do in open and large cropped areas,” he said.
“Different stingless bee species have been tested successfully in protected cultivation of tomatoes, green peppers, hot peppers, seedless watermelons, strawberries and melons,” he added. “Other crops can also benefit from their pollination services, it is only a matter of conducting more studies to determine which ones.”
Freitas urges caution, though, with moving bees around the world. “History has shown a series of problems, such as the spread of diseases within and between species, when we moved bees out of their native areas,” he said, citing as examples Africanized honeybees that were brought to the Americas and exotic bumble bees species introduced in Israel and Argentina. “If stingless bees are to be introduced in countries where they are not native, careful studies should be done to make sure they will not become the vector of any diseases or become naturalized in local environments where they might cause ecological disturbances.”
He believes those who may not have heard about stingless bees will be hearing a lot more about them. That’s because he sees stingless bees playing an important role in two distinct fronts.
One of those is diversifying the pool of pollinators and increasing the amount of them in tropical areas where they are indigenous. “For that to happen,” he said, “it is only necessary for growers to understand the role of these bees and to adopt some pollinator-friendly practices to stimulate their presence in and around cropped areas.
The other is that stingless bees are destined for increased use as pollinators in protected cultivation. “I believe this kind of agriculture will grow a lot with the climate changes to come,” he said.
Stingless bee honey, U.S. beekeepers will be interested to know, is only available in small amounts because stingless bee colonies are much smaller than honey bee colonies. A stingless bees colony produces only 1-2 liters of honey per year compared to as much as 200-300 pounds of honey generated annually by a honey bee colony. It’s also stored in the hive in vessels of wax or cumen called pots, hence the name pot honey, rather than in the familiar double-sided hexagonal combs created by honey bee colonies. In another time, the conquistadores sent the wax back to Europe to make candles and seals on official documents. It is still used today for similar purposes.
Because stingless bee honey is only available in small amounts and in the local areas where it is produced, it is expensive, costing as much as $20 to $40 per liter. It is also highly valued as a medicinal product for the treatment of cataracts and to ease childbirth, especially by traditional Mayan medicine practitioners.
The honey is watery compared to honeybee honey, said Dr. Kwame Aidoo of the International Stingless Bee Centre in Cape Coast, Ghana. But that doesn’t hurt the taste. Quite the opposite. Stingless bees make the world’s best honey, said Buchmann, who proudly claims to have sampled honey from many different stingless bee species. M. beechii produces his favorite honey. “It’s intensely floral,” he said. “Just magical.”
For additional information about Melipona beecheii, watch the 7-minute video about this fascinating species below:
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