Since around 2002, farmers in Odisha have been noticing that fewer bees visit their fields each year. It was not just one single species of bees that began to disappear, but several, many of which farmers knew were linked to the health of their fields. They are not alone. For years, similar anecdotal information has been streaming in from farmers in places as far apart as Punjab and Kerala, Maharashtra and Tripura. Scientists so far have found it difficult to verify this information, largely because of the lack of already existing data to compare it with. A study published in the peer-reviewed journal Biological Conservation in May 2017 now tries to augment India’s information by looking at data from farmers instead.
“We asked farmers if they could identify various kinds of bees and they actually stated the percentage-wise declines of these bee populations in this area,” said Parthib Basu, a co-author of the study, and lead scientist at the Centre for Pollination Studies, which comes under the Department of Zoology at the University of Calcutta. “These are perhaps first-ever published accounts of such a decline in such terms from India.”
The study confirms a view that has been considered unorthodox by some in the scientific community – that those who live on the land are often its closest observers and that their contributions to scientific knowledge should not be dismissed.
Ominous reports of bee colonies collapsing seemingly without reason have been reported around the world at least since 2006. Reports of species extinctions have become increasingly common in the last few decades, but the case of bees has particularly alarming implications for human existence.
This is because bees are pollinators, which is to say that they help plants to transfer pollen from male to female parts and so help in fertilisation. While staple crops such as paddy and wheat self-pollinate, many vegetables and fruits rely heavily on external pollinators such as bees to reproduce. In the absence of these pollinators, productivity might decline as much as 80% for some plant species.
The mystery has perplexed scientists around the world for 20 years now. Three studies released around 2012 narrowed down the cause to neonicotinoids, a very popular class of pesticides that can be lethal for bees’ functioning. Studies after that have complicated the adverse relationship between bees and pesticides, linking their decline also to intensive agriculture that is known to contribute to lower biodiversity.
India might not have monocropping on the vast scale of Europe or North America, but many of its farmers do practice intensive agriculture – where land is not being deforested and consumed for industrial purposes.
This and other studies from the Centre for Pollination Studies make perhaps the most significant contribution to the growing knowledge base around bees in India. Since 2011, Basu and his team of scientists, along with local field workers – all of whom are mentioned as co-authors in these papers for their work in collecting data – have been documenting different aspects of the bees’ decline, including higher rates of oxidation in honey bees exposed to pesticides, which makes them age faster.
As expected, land with lower pesticide use had higher diversity of bee species, according to another study from the centre. A third study showed that bees exposed to pesticide stress lost their sense of smell due to warping of their antennae – and so were unable to return to their hives, which contributes, again, both to their eventual starvation and to the collapse of the hive at large.
“These changes must have been taking place with the introduction of pesticides over the last four to five decades,” Basu said. “We started with farmers’ perceptions that bees were reducing and now we also know the reasons.”
Source: Scroll.in, June 5, 2017
https://scroll.in/article/839067/bees-are-disappearing-in-india-and-we-…
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