A common pesticide used on apple trees may make it harder for bumblebees to pollinate the trees properly and thus producing poorer quality fruit.
Bumblebees pollinating apple trees that become exposed to neonicotinoid pesticides demonstrate a decrease in their ability to pollinate the trees effectively. Researchers found that the pesticide causes bees to visit fewer flowers and carry less pollen, resulting in apples that contain fewer seeds and fruits of poorer quality.
"One of the important things about our work is that it highlights the importance of pollination services," said Royal Holloway University of London's Dara Stanley, one of the study's lead authors. She added that this paper is one of the first to study how bumblebees and their ability to pollinate are affected by pesticides commonly used on trees and flowers.
The researchers used three bumblebee groups for this experiment. The first two groups were exposed to two different levels of pesticide meant to simulate pesticide levels normally used in the field. One group was exposed to 2.4 parts per billion; another at 10 parts per billion. The third group remained unexposed to pesticides.
Unsurprisingly, the group exposed to 10 parts per billion pesticide level suffered the most detrimental effects of lower quality fruits and decreased agricultural production.
"If exposure to pesticides alters pollination services to apple crops, it is likely that these other bee-pollinated crops would also be affected. Most importantly, the majority of wild plant species benefit from insect pollination services," the researchers wrote in their paper.
Neonicotinoid, or commonly known as neonic pesticides, are regularly used to keep pests away from many different plants such as corn and soybeans. Neonics remain with the plant after application even as it grows, thus the pesticide protection remains with it for a very long time.
However, the pesticide was also shown to affect insects that are beneficial to plants such as bees. Studies have found that pesticides have a negative impact on bee reproduction and behavior.
Experts recommend that further studies are needed to understand whether these negative effects will also affect agricultural production and what can be done to remediate the problem. Reducing pesticide use on plants or creating areas with lower pesticide levels can also help.
The researchers' paper is published in the Nature journal.
