Air pollution killing giant Asian honey bees: Study
MUMBAI: The giant Asian honey bee or apis dorsata, which produces more than 80% of India’s honey, is falling prey to air pollution, according to a first-of-itskind analysis of the impact of air pollution on insects by the National Centre for Biological Sciences (NCBS), Bengaluru, which is a centre of the Tata Institute of Fundamental Research.
A four-year study of over 1,800 apis dorsata found that more than 80% of the bees collected from moderate and highly-polluted sites died within 24 hours in Bengaluru as compared to less polluted areas where the number of dead bees was less by 20%. In addition to NCBS, collaborators on the study include Massachusetts Institute of Technology, Cambridge; Institute for Stem Cell Science and Regenerative Medicine (instem), Bengaluru; Knightcardiovascularinstitute; and the department of medicine and molecular and medical genetics at the Oregon Health and Science University, Portland. The study was published in the Proceedings of the National Academy of Sciences, the United States of America, on Tuesday.
Results also revealed that the rate at which giant Asian honey bees visited flowers was lower in more polluted areas. Additionally, bees from more polluted areas showed irregular heartbeats, lower blood cell count among others. Bee debris also containedseveraltoxicelements.
While the sites in the study are specific to Bengaluru, Shannon B Olsson, lead author and associate professor at NCBS’S naturalistinspired chemical ecology laboratory, said the heath of wild bees in more polluted cities such as Delhi and Mumbai are likely be severely impacted. “In a city like Delhi, which is among the top 10 polluted cities in the world, there are likely to be more severe effects on bees than in Bengaluru, but there may not be the same exact impacts since the sources and components of air pollution are different in the two cities,” said Olsson.
“India is home to nine of the world’s 10 most polluted cities, but we have no idea of the impact of air pollution on plant and animal systems. The importance of bees and other pollinators to India’s plant biodiversity and agro-economy cannot be overstated,” she added.
India is the world’s largest fruit producer, second-largest vegetable producer and the second-most populous country. Scientists said the findings offer important contributions to the understanding of India’s food security and ecosystems. Geetha Thimmegowda, another lead author and a postdoctoral researcher at NCBS, said, “Such studies are imperative to reveal the full impact of air pollution not only on humans and environmental ecosystem, but also economic loss to pollinatordependent crops and food security in highly-polluted and vulnerable regions such as India.”
Arunabha Ghosh, founder and CEO of the Council on Energy, Environment and Water, said much of the air quality studies in India have either considered sources of pollution or impact on human health, and to an extent on economic productivity. “This study covers important new ground by examining the impact of air pollution on pollinators, which would have serious implications for agricultural output in India. Such findings underscore the need to raise India’s ambient air quality standards,” he said.
The impact of poor air quality did not just take its toll on apis dorsata. Experiments undertaken with drosophila melanogaster (fruit fly) reared in the laboratory displayed similar effects when exposed to air pollution.
Researchers said this suggests the impact is not species-specific nor likely the result of other environmental factors.
“This study provides us with hard evidence that all is not well with our wild bees since it was done with wild bees naturally visiting flowers in Bengaluru city and not in lab assays on reared honey bees kept in hive boxes that may already be stressed or immuno-compromised,” said Hema Somanathan, who studies bee behaviour and pollination ecology at the Behavioural and Evolutionary Ecology (BEE) laboratory at the Indian Institute of Science Education and Research, Thiruvananthapuram, and who was not involved in the study.
Researchers said more than 80% of all flowering plants rely on animal pollination, and that India’s annual mango export could stand to lose over ₹65,000 lakh because 53% mangoes would disappear without insect pollinators like honey bees.