Scientists have demonstrated for the first time that popular pesticides called neonicotinoids disrupt bumblebees' ability to pollinate.

Bees are responsible for the pollination of some of the world's most important crops, but have been experiencing significant population declines in recent years, Royal Holloway University reported. Until now, researchers were unclear as to what affect these widespread pesticides had on bees' pollination services.

A team of researchers observed that bumblebees exposed to real-world levels of neonicotinoid pesticides collected pollen from apple trees and flowers less frequently. Trees pollinated by bumblebees exposed to pesticides produced apples with 36% fewer seeds, which could have a significant influence on fruit quality.

"We found effects of neonicotinoid pesticide exposure on crop pollination services provided by bumblebees at the colony level. To our knowledge this is the first study to examine the impacts of pesticides not just on bees themselves, but on the crucial pollination services they provide to crops and wild plants," said lead author Dara Stanley, School of Biological Sciences at Royal Holloway.

To make their findings, the researchers looked at three groups of bumblebees exposed to varying levels of neonicotinoid pesticides in a controlled setting for a period of 13 days. Two of these groups were exposed to levels of pesticides typically found in agriculture environments, while the third control group was not exposed to any pesticides. Their findings suggest bees exposed to varying levels of pesticides behave differently towards flowers than those not exposed.

"Bumblebees are major pollinators of apples and many crops around the world. The findings of this study have important implications for both society and the economy, as insect pollination services to crops are worth at least $361 Billion worldwide every year, and are vital to the functioning of natural ecosystem," said professor Nigel Raine, formerly from the School of Biological Sciences at Royal Holloway, University of London.

The findings were published in a recent edition of the journal Nature.