When a Cornell-led team of scientists analyzed two dozen environmental factors to understand bumblebee population declines and range contractions, they expected to find stressors like changes in land use, geography or insecticides.
Instead, they found a shocker: fungicides, commonly thought to have no impact.
“Insecticides work; they kill insects. Fungicides have been largely overlooked because they are not targeted for insects, but fungicides may not be quite as benign – toward bumblebees – as we once thought. This surprised us,” said Scott McArt, assistant professor of entomology and the lead author on a new study published Nov. 15 in the journal Proceedings of the Royal Society B.
While science has studied insecticides, such as neonicotinoids, that attack bugs’ central nervous systems, this new work shows how fungicides – particularly chlorothalonil, a general-use fungicide often found in bumblebee and honeybee hives – may negatively affect bee health, said McArt, a fellow at Cornell’s Atkinson Center for a Sustainable Future.
Building on a large data set collected by Sydney Cameron, professor of entomology at the University of Illinois, the scientists discovered what they call “landscape-scale” connections between fungicide usage, pathogen prevalence and declines of endangered United States bumblebees. (Landscape scale refers to the area in which foraging bumblebees live, about 2 kilometers in diameter.)
While fungicides control plant pathogens in crops, the bees pick up their residue when foraging for pollen and nectar. As farms use both insecticides and fungicides, the scientists worry about synergy. “While most fungicides are relatively nontoxic to bees, many are known to interact synergistically with insecticides, greatly increasing their toxicity to the bees,” McArt said.
Chlorothalonil has been linked to stunted colony growth in bumblebees and an increased vulnerability to Nosema, a fatal gut infection in bumblebees and honeybees.
“Nosema can be devastating to bumblebees and honeybees,” said McArt. “Since fungicide exposure can increase susceptibility of bees to Nosema, this may be the reason we’re seeing links between fungicide exposure, Nosema prevalence and bumblebee declines across the United States in this data set.”
For domestic and global agriculture, bumblebees are a key component due to their ability to use “buzz pollination” that vibrates and shakes pollen loose from flowers. In the United States, bees contribute more than $15 billion to the economy and $170 billion to global agribusiness, according to global economic research and a 2012 Cornell study. While half of crop pollination work is done by commercially managed honeybees in the U.S., the other half is done by bumblebees and wild bees. In New York, pollination services contribute $500 million to the state’s agricultural economy.
McArt and his Cornell colleagues will continue to investigate fungicide-insecticide synergisms and fungicide-pathogen interactions under the New York State Pollinator Protection Plan and a new grant from the New York Farm Viability Institute.
The Latest on: Bee decline
- Activists dressed as bees set Christchurch City Council meeting abuzzon June 25, 2020 at 9:20 pm
A hive of “bees” swarmed a Christchurch City Council public meeting this morning as climate activists highlighted the plight of insects. In today’s hearing of verbal submissions for the council’s ...
- Bees need changing-weather protectionon June 24, 2020 at 11:00 pm
Honey bees and other pollinators are critically important to securing the nation’s food supply and providing ecosystem services that insure plant diversity, soil stability and species richness. Fruit ...
- Bubble-blowing drone could help pollinate flowers when no bees are aroundon June 24, 2020 at 12:49 pm
Could a a bubble-blowing drone help fill in for declining bee populations when it comes to pollinating flowers? It sounds crazy. It might just work.
- Are honey bees colonies coming back? Study says maybeon June 23, 2020 at 8:32 am
The buzz of honey bees may be coming back. Beekeepers were recently surveyed and they reported having only lost 22.2% of their colonies from Oct. 1 to March 31. The usual average rate of colony loss ...
- A Record Number of Bees Died Last Summeron June 22, 2020 at 11:09 am
It’s been a bad year for bees. According to the preliminary results of the University of Maryland’s annual survey, U.S. beekeepers lost 43.7% of their honey bees from April 2019 to April 2020. That’s ...
- Soap Bubbles Can Pollinate Flowers, but Can They Replace Bees?on June 22, 2020 at 9:32 am
In a paper published this week in iScience, scientists at the Japan Advanced Institute of Science and Technology show that specially designed soap bubbles can deliver grains of pollen to flowering ...
- Teenagers create 13-mile 'Bee Byway' in their town to save native beeson June 17, 2020 at 10:48 pm
Joshua Nichols and Luke Marston are using their STEM skills to save the bees. The bee population is quickly declining in the United States, with urbanization leading to the fragmentation of their ...
- Former Bumble Bee CEO Gets 40 Months in Jail for Tuna Price Fixingon June 17, 2020 at 7:09 pm
The CEO of Bumble Bee Foods has been sentenced to jail two years after he was charged with conspiring with competitors to fix prices for canned tuna. Christopher Lischewski was found to be a leader of ...
- Scientists find way to pollinate plants with soap bubbles as bees declineon June 17, 2020 at 1:45 pm
"It sounds somewhat like fantasy, but the functional soap bubble allows effective pollination and assures that the quality of fruits is the same as with conventional hand pollinat ...
- With bees in short supply, soap bubbles could assist with pollination, study findson June 17, 2020 at 8:00 am
For us to keep enjoying apples, melons and blueberries, bee populations have to be kept healthy and well. If all else fails in efforts to save them, pollinating flowers with soap bubbles could work, a ...
via Google News and Bing News