Researchers from Nagaland University have identified stingless bee species that can pollinate efficiently to increase agricultural yield. This finding, the researchers claim, could significantly boost polyhouse farming in the country.
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The study found that the stingless bee species — Tetragonula iridipennis Smith and Lepidotrigona arcifera Cockerell — when introduced under greenhouse conditions, were able to pollinate around 10 crops, including chilli, cucumber, watermelon, and squash varieties such as pumpkin.
Avinash Chauhan, scientist and principal investigator (AICRP Honeybees & Pollinators), Department of Entomology, School of Agricultural Sciences, Nagaland University, confirms the details: “Stingless bees have a limited range of 50 to 100 metres and can withstand temperatures of up to 40 degrees Celsius. In contrast, the rock bee, Apis dorsata, which is an important pollinator in open conditions, on the other hand, has a much wider range and cannot be confined within a polyhouse,” he points out.
Other qualities that make stingless bees ideal for pollination in confined spaces are their floral fidelity and stingless nature. “These bees return to the same flower until they fully exploit the nectar; this fidelity to flowers qualifies them as excellent pollinators. They don’t sting either, sparing farmers the discomfort,” Chauhan says.
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Honey being extracted from stingless bees. Image by Avinash Chauhan.
Pollinating in a polyhouse
India is experiencing a sharp decline in invertebrate pollinator species — and we are beginning to feel the sting.
A drop in the pollinator population could also threaten the country’s food security. A 2023 paper cites a report by the Agricultural and Processed Food Products Export Development Authority (APEDA), which shows that honeybees alone contribute to approximately 20% of total crop yield in India. The study states that more than half of all crop yields depend on insect pollinators, while 34% of oilseeds and around 15% of fruit production rely significantly on them. This is especially noteworthy given that the 2023-2024 Economic Survey reports that the agriculture sector s for 18.2% of India’s GDP and provides livelihood to about 42.3% of the population.
However, statistics also reveal a reduction in agricultural land area due to various factors, including urbanisation. This is where greenhouse or polyhouse farming gains significance, with its potential to produce crops in substantially smaller spaces.
Stingless bees, or Meliponini in the family Apidae, were earlier considered to be tropical bees, but some species are also found in temperate and sub-temperate regions. Of the 27 species of stingless bees identified in India, Nagaland is home to six.
Stingless bee pollinating chilli flowers. Image by Avinash Chauhan.
Some of the crucial findings of this study include a significant increase in yield in chilli varieties when pollinated by stingless bees. A press release from the University notes, “In king chilli, the percent fruit set increased to 29.46% compared to non-pollinated crops (21.00%). Likewise, in chilli (Capsicum annuum), the fruit set and healthy fruits increased by 7.42% and 7.92%, respectively, over non-pollinated ones. Similarly, seed weight — an indicator of viability or germination — increased by 60.74% when pollinated by stingless bees.”
Soubadra Devy, senior fellow at the Ashoka Trust for Research in Ecology and the Environment (ATREE), however, feels that crop pollination should be carried out by a diversity of pollinators for healthier crops. “Polyhouse environments could also breed diseases; it’s not the ideal condition for crop pollination. It is similar to monoculture,” she says.
She points to a study she led to assess pollination in the city (Bengaluru) during extreme weather conditions — both during excessive rainfall and drought. The researchers noticed a clear drop in yield during drought, likely due to fewer female flowers and a shift in the pollinator community, notably a sharp decline in the population of the critical pollinator Trigona sp., or stingless bee. “We found that stingless bees did not survive extreme heat; pollination during the drought was largely carried out by A. dorsata,” Devy says, underscoring her apprehensions about the survival of stingless bee species in polyhouse heat during summer.
The meliponiary at School of Agricultural Sciences, Nagaland University. Image by Avinash Chauhan.
Latest buzz in the box
Nagaland University researchers also highlight the stingless bee’s potential to produce honey as an additional benefit for farmers who rear them. Chauhan says that stingless bees often pollinate small flora, including medicinal plants, and their honey is known for its antibacterial and antifungal properties. “The propolis — a resin-like substance made by bees — is also medicinal in nature and has good demand in the market.”
The researchers have developed special brood boxes for stingless bee apiaries to help farmers make the most of these tiny bees. “Stingless bees seal their hives very well using hardy propolis. Their nest structure is such that the brood, honey, and pollen are all stored together in one chamber. Farmers who harvest this honey often use hammers and chisels to break open the chambers, leading to the brood and pollen getting mixed with the honey, which results in fermentation,” he explains. As a solution, the brood boxes have been designed with separate chambers for honey, and bee behaviour has been manipulated so that the bees store honey apart from the brood and pollen, he adds.
As for the next steps in the research, Chauhan says that going forward, the focus will be on crops that are in higher demand globally, as well as on developing improved extraction techniques for honey produced by stingless bees. “The medicinal properties of the honey will also be analysed through proper testing and melissopalynological studies (pollen analysis to determine botanical and geographical origin),” he says.
This article originally appeared on Mongabay. Read the original article here