A groundbreaking study published in Nature reveals for the first time the direct impact of declining pollinating insects on human health. In Nepal, they represent 44% of agricultural income for families and provide over 20% of vitamin A, folate, and vitamin E intake. These figures transform biodiversity conservation into a global public health issue.
The essentials
- A study of ten Nepalese villages quantifies for the first time the impact of pollinators on human health
- Wild insects generate 44% of agricultural income and 20% of key vitamins in diets
- A quarter of the world’s population suffers from nutritional deficiencies aggravated by pollinator decline
- The University of Bristol measured yields of 17 crops over three years in the Nepalese Himalayas
44% of family income depends on six legs and a pair of wings
The University of Bristol figures break a taboo: the link between insects and human health had never been directly measured. The study covers ten villages in the Nepalese Himalayas where researchers tracked yields of 17 different crops over three years. The result: wild pollinators—bees, bumblebees, hoverflies, and butterflies—are responsible for 44% of the agricultural income of the 600 families studied.
This economic dependency reflects a biological reality. The most profitable crops—squash, cucumbers, tomatoes, and beans—require cross-pollination that only insects can provide. Without them, squash yields drop by 95%, cucumber yields by 80%. Self-pollinating vegetables like rice or cereals remain stable, but they generate three times less revenue per hectare.
The Bristol team observed that families suffer substantial financial losses when pollinator populations decline. In an economy where median income reaches $4,800, these losses equate to closing schools to children or forgoing healthcare.
Vitamin A, E, and folate deficiency: the hidden face of insect extinction
The most striking discovery concerns nutrition. Insect-pollinated crops provide 40% of vitamin A, 13% of vitamin E, and 8% of folates consumed by the families studied. These micronutrients prevent blindness, strengthen the immune system, and reduce birth defects.
The British researchers analyzed the nutritional content of 1,200 meals in Nepalese villages over two years. They discovered that families whose plots harbor the most pollinating insects consume 35% more vitamin A than their neighbors. The gap reaches 28% for vitamin E and 19% for folates.
This correlation reveals a perverse mechanism: as pollinators disappear, diets become impoverished in essential micronutrients. Farmers compensate by cultivating more cereals, but they lose the nutritional diversity that only vegetables and fruits can provide.
The World Health Organization estimates that 2 billion people suffer from micronutrient deficiencies, called “hidden hunger.” This invisible malnutrition primarily affects South Asia and sub-Saharan Africa, where 70% of the planet’s wild pollinators also live.
Asia is losing its pollinators twice as fast as Europe
Pollinating insect decline strikes Asia with particular violence. Pollinator populations show signs of accelerated decline in South Asia compared to Europe.
This catastrophe is explained by three converging factors. The use of neonicotinoids tripled in India and Bangladesh between 2010 and 2024. These systemic insecticides kill pollinators even at low doses: a concentration of 2.5 nanograms per gram of pollen is sufficient to disorient bees and reduce their reproduction by 40%.
Rapid urbanization simultaneously destroys natural habitats. In China, soil artificialisation progresses by 1.2% per year, eliminating the flowering meadows and hedgerows where wild pollinators nest. In Nepal, deforestation for agriculture eliminates 2.3% of forest each year, reducing refuge zones for insects accordingly.
Climate change aggravates this pressure. Average temperatures have risen by 1.8°C in the Himalayas since 1975, forcing pollinating species to migrate to higher altitudes. But wild flowers do not follow the same pace: the temporal mismatch between flowering and pollinator presence now stretches over three weeks, compared to just one in 1990.
Less productive and more fragile agriculture
The collapse of pollinators is transforming Asian agriculture. Yields of many major crops—including tomatoes, cucumbers, and squash—show a downward trend in regions where insects are declining most rapidly.
This productivity decline forces farmers to expand their cultivated land. In Bangladesh, the area devoted to vegetables increased by 23% between 2018 and 2025 to maintain constant production. This expansion comes at the expense of natural zones that precisely harbored pollinators.
Attempts at artificial pollination remain marginal. In China, 140,000 farmers hand-pollinate their pear orchards in Sichuan Province. This technique requires 15 hours of labor per hectare compared to 30 minutes for a bee colony. Production costs increase by 60%, making Chinese fruits less competitive on international markets.
Ecological instability amplifies in parallel. Monocultures replace diversified agricultural systems that better resisted pests and climate variations. This simplification exposes crops to brutal collapses: in 2024, a pathogenic fungus destroyed 40% of squash harvests in Pakistan, depriving 2.3 million people of their primary source of vitamin A.
The global economic bill represents a major challenge
Economists are beginning to quantify the global impact of pollinator decline. Robert Costanza, of the Australian Institute of Environmental Policy, values services provided by pollinating insects at $235 billion per year. This estimate covers only the market value of harvests, without including the health costs of nutritional deficiencies.
The Nepalese study allows this calculation to be refined. If its results are extrapolated to the approximately 420 million family farms in Asia (out of a global total of 570 million farms), the income loss represents a considerable sum. Additional health expenditures to treat vitamin deficiencies add several billion according to WHO estimates.
This bill constitutes a major economic issue that rivals the costs of climate warming in Asia. Yet public policies largely ignore this silent crisis. Budgets devoted to pollinator preservation represent less than 0.1% of agricultural spending in the countries studied.
A few initiatives are nonetheless emerging. India banned three neonicotinoids in 2025 and finances a network of 12,000 ecological corridors to connect fragmented habitats. Nepal has been testing “pollinator highways” since 2024: flowering strips 50 meters wide that cross intensive agricultural zones. Initial results show a 30% increase in wild bee populations and an 18% increase in agricultural yields within a two-kilometer radius.
These experiments remain isolated against the scale of the challenge. The Amazon is collapsing twenty years earlier than expected, revealing that ecosystems are collapsing faster than anticipated. The pollinator crisis follows the same accelerated trajectory.