Bombus impatiens nectaring on Lantana sp. in Okemos, Michigan. Photo taken September 24, 2017 by F. W. Ravlin. Canon 5D Mark III, 100 mm macro.
Pyrethroid pesticides are effective. Sometimes too effective.
Researchers at Michigan State University’s entomology department have unlocked a key to maintain the insecticide’s effectiveness in eliminating pests without killing beneficial bugs, such as bees. The study, featured in the current issue of Proceedings of the National Academy of Sciences, shows that molecular tweaks can make the difference.
Pyrethroids target the voltage-gated sodium channel, a protein found in nerve and muscle cells used for rapid electrical signaling. Pyrethroids basically work by binding to the voltage gate of the sodium channel and prevent it from closing. The nervous system becomes over-stimulated and the insect is killed. These pesticides, however, don’t have the same effect on humans, or other mammals for that matter.
Ke Dong, MSU insect toxicologist and neurobiologist and co-author of the paper, honed in on a single protein that could afford bumble bees the same resistance as humans – tau-fluvalinate, a pyrethroid insecticide. Dong worked with Shaoying Wu, lead author from Henan Agricultural University (China), who conducted the research in Dong’s lab as a visiting scholar.
“For the first time we are showing that unique structural features in bee sodium channels interfere with the binding of tau-fluvalinate to bumble bee sodium channels,” Dong said. “This opens the possibility of designing new chemicals that target sodium channels of pests but spare bees.”
Sodium channels are large transmembrane proteins of more than 2,000 amino acid residues. Dong’s lab spent many years unraveling this groundbreaking advance. The scientists initially started with sodium channels from other bugs, such as mosquitoes, fruit flies, cockroaches, mites and ticks, to find where pyrethroids bind on insect sodium channels to effectively kill them. They got some help from nature.
“By examining wild mosquitoes that have become resistant to pyrethroids, we were able to help narrow down the potential sites on which to focus,” Dong said.
Specifically, in a previous study, Dong and the team identified mutations that made the channels more resistant to pyrethroids. Working with Boris Zhorov, a computer modeling expert from McMaster University in Canada, they identified two distinct pyrethroid binding sites on insect sodium channels. They also uncovered the molecular differences between mammals’ and insects’ differing reactions to pyrethroids.
For the current study, the team focused on a longstanding enigma that bumble bees and honey bees are highly sensitive to most pyrethroids, but they were resistant to tau-fluvalinate. Currently, tau-fluvalinate is widely used to control agricultural pests and also varroa mites, which are one of the biggest threats to bees worldwide.
Eventually, the team discovered that the channel is resistant to tau-fluvalinate but sensitive to other pyrethroids. Further mutational analysis and computer modeling revealed that specific amino acid residues in bumble bee sodium channels are responsible for the selective toxicity.
Future research will examine sodium channels from various pest and beneficial insects to explore the features of pyrethroid binding sites, which could lay the groundwork for designing new and selective pesticides. It also will shed light on how pests develop resistance to insecticides over time and how beneficial insects respond to them in the field.
Learn more: REFINING PESTICIDES TO KILL PESTS, NOT BEES
Check this out if you are interested in beekeeping: Flowers Across Sydney
The Latest on: Pesticides
via Google News
The Latest on: Pesticides
- Striking A Regulatory Balance Between Hemp And Pesticideson November 29, 2019 at 8:40 pm
There are no pesticides registered by the Environmental Protection Agency (EPA) specifically for use on hemp. However, according to the National Law Review, there are six federally registered ...
- Peer Pressure Linked To Fertilizers And Pesticides On Lawns; Could Wildflowers Follow?on November 29, 2019 at 9:43 am
If your neighbors have a green, treated lawn, you may be likely to have one too: a space dedicated to fertilizers, pesticides and regular watering. That’s according to a National Science ...
- Health Canada data reveals roughly 95% of pot samples tested negative for pesticideson November 29, 2019 at 7:15 am
4:18 Next phase of Canada’s cannabis legalization takes effect WATCH ABOVE: Next phase of Canada's cannabis legalization takes effect Health Canada testing has found that roughly 95% of pot samples ...
- Maharashtra to permit co-marketing of pesticideson November 28, 2019 at 11:39 am
The pesticides sold under co-marketing route needed to be property labelled with the name of the manufacturer and the marketing company properly displayed. The Maharashtra Agriculture department has ...
- Red kite died after being poisoned by 'highly toxic' pesticideson November 28, 2019 at 1:54 am
Further tests have now revealed the presence of two pesticides and concluded that this was most likely the cause of the bird’s death, particularly given it was fit and healthy and had died soon after ...
- On balance, some neonicotinoid pesticides could benefit bees: studyon November 27, 2019 at 5:02 am
The story of neonicotinoids is growing more nuanced. Europe has banned outdoor use of three of these insecticides to protect bee populations. Two other neonicotinoids are still permitted, but little ...
- Thailand Decides Against Pesticides Ban After U.S. Pressureon November 27, 2019 at 1:46 am
Thailand backed down on a plan to prohibit three pesticides from Dec. 1 after coming under pressure from farmers, the U.S. government and lobbyists for chemicals companies. The ban on paraquat and ...
- U.S. Protests Thailand's Plan To Ban 3 Pesticideson November 27, 2019 at 1:09 am
Thailand will ban three popular pesticides starting Sunday over public health concerns. Many farmers aren't happy. The U.S. government is urging Thai officials to reconsider.
- German farmers protest government restrictions on fertilizers, pesticideson November 26, 2019 at 6:40 pm
Nov. 26 (UPI) --Thousands of farmers in Germany parked their tractors outside Berlin's Brandenburg Gate on Tuesday in protest of government restrictions on fertilizers, pesticides and insecticides.
- Demonstrators Call on Thai Government to Delay Pesticides Banon November 25, 2019 at 8:51 pm
About 2,000 demonstrators marched to Thailand’s Government House on Tuesday to demand a delay in a ban due from Dec. 1 on three pesticides, as a dispute over the plan escalates. The protesters ...
via Bing News