Guess the replies if you ask if wasps and flies have any virtues. Many people wish them extinct, but they are important pollinators along with wild bees, honeybees, and lepidoptera.
The decline of 1-2% per year in insect populations around the world theoretically reduces agricultural yields. I thought it would be hard to measure the impact, so a paper published this week by the Harvard School of Public Health came as a surprise. The authors estimate pollination failure causes a 3-5% deficit of agricultural productivity in fruit, vegetables, and nuts. The loss of healthy food accounts for 427,000 excess annual deaths.
The data come from experimental farms across four continents monitoring gaps in product yields that depend on pollination. A global disease risk model was applied to estimate the impacts on dietary risks and mortality in different countries.
The economic costs fell mainly on low-income country providers of food. But the health burden fell mainly on middle-income countries, including China and India, because of the relative prevalence of metabolism-related diseases compared to communicable diseases among poor people. The proximate culprits are climate change and loss of biodiversity. We see in our mirrors those ultimately responsible for agricultural shortfalls from disappearing pollinators.