by Staff Writers
Ithaca NY (SPX) Nov 16, 2017
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.
Brisbane, Australia (SPX) Nov 14, 2017
A new type of cell has been found in the eye of a deep-sea fish, and scientists say the discovery opens a new world of understanding about vision in a variety of light conditions. University of Queensland scientists found the new cell type in the deep-sea pearlside fish (Maurolicus spp.), which have an unusual visual system adapted for twilight conditions. Dr Fanny de Busserolles at ... read more
Darwin Today At TerraDaily.com
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|