Sector News

Glyphosate disrupts honey bee gut bacteria

October 3, 2018
Energy & Chemical Value Chain

Glyphosate is among the most widely used agricultural chemicals in the world, and the companies that make it describe it as safer and more environmentally-friendly than other herbicides.

But a group of researchers in Texas now report that the weed killer, sold as Roundup, could harm honeybees indirectly by disrupting the bacteria in their guts (Proc. Natl. Acad. Sci. USA 2018, DOI: 10.1073/pnas.1803880115). The scientists think the findings could help explain the decline in honeybees observed over the past decade or so.

The team, led by Nancy Moran, an expert in bee biology at the University of Texas, Austin, treated hundreds of worker bees with glyphosate at concentrations they might encounter while foraging near agricultural fields, reintroduced them into their hive, and then analyzed the gut bacteria of treated and untreated bees in the hive. After three days, the researchers found that the abundance of some of the eight predominant species fell in treated bees compared with untreated ones, suggesting that exposure to glyphosate changed the composition of the bees’ guts. When challenged with a common bee pathogen, the worker bees exposed to glyphosate died at higher rates than unexposed bees, suggesting that the bacterial shake-up made the insects more vulnerable.

The conclusions match previous reports demonstrating that honeybees with compromised gut flora are malnourished and susceptible to infection. Those findings, along with data showing that glyphosate can affect soil bacteria and accumulate in bee honey and hives, indicate that researchers should explore whether possible off-target effects of the popular herbicide have played a role in honey bee decline, Moran says.

About 10 years ago, there was a noted die-off of honeybees, later termed colony collapse disorder. Mortality rates have continued to be high, Moran says, but the die-offs haven’t been as sudden. Researchers have been looking at the role of pesticides and fungicides in the decline, as well as infection. But glyphosate hasn’t really been part of those earlier conversations, says Fred Gould, an entomologist and plant pathologist at North Carolina State University. The field, he says, is “getting better at looking for subtle off-target effects,” such as those described in the new study.

As an herbicide, glyphosate works by blocking an enzyme called EPSP synthase in plants and microbes needed to create aromatic amino acids like phenylalanine and tryptophan. Glyphosate doesn’t kill microbes, but it keeps them from growing, and most bacteria found in bee guts carry the gene for the enzyme.

Bottom of Form

But while some species of bacteria in bee guts were susceptible to glyphosate, others were less so, either because they carried a gene for a glyphosate-resistant version of EPSPS, or because of other unknown mechanisms, Moran says. Her group next plans to repeat their experiments on whole hives, and to explore the nonEPSPS resistance mechanisms.

The environmental impact and health effects of glyphosate form a contentious issue, Gould says, so whole hive studies could shed light on the herbicide’s effects on a critical species for agriculture.

These studies also could help guide how to avoid possible negative effects of glyphosate on honeybees. The likely outcome will be some sort of best practices on when and where to spray glyphosate, says Juliana Rangel, an entomologist at Texas A&M University. Pollination via honeybees is an approximately $15 billion per year industry, she says, and “a lot of times, these tragedies can be avoided with a better understanding of the system.”

By: Megha Satyanarayana

Source: cen

comments closed

Related News

July 14, 2024

Europe ethylene spot prices turn firmer on demand, feedstock, looming cracker turnarounds

Energy & Chemical Value Chain

European ethylene spot prices have firmed week on week on the back of better-than-expected demand amid higher feedstock values and an increasing focus on upcoming planned cracker maintenance outages. Spot deals this week have been reported at discounts of 32-35% on the pipeline, prior deals had been at discounts of around 38-39%.

July 14, 2024

Marcel Imwinkelried appointed new Siegfried CEO

Energy & Chemical Value Chain

He will succeed Reto Suter, who has led the Siegfried Group as CEO ad interim since the departure of Wolfgang Wienand on May 1, 2024. Suter will now focus on his role as Chief Financial Officer for Siegfried. Wienand will become CEO of Swiss competitor Lonza.

July 14, 2024

Honeywell acquires Air Products’ LNG technology, business for $1.8B

Energy & Chemical Value Chain

Honeywell Inc. (Charlotte, North Carolina) has reached agreement to acquire Air Products’ (Leigh Valley, Pennsylvania) liquefied natural gas process technology and equipment business for $1.81 billion. The deal is expected to close before the end of the year. The price represents a multiple of 13 times the unit’s estimated 2024 EBITDA.

How can we help you?

We're easy to reach