Tuesday , July 5 2022

Neonikotinoid insecticides cause bees to leave their young at night: study – Science News


Spying on the bumblebees while the nest reveals strange behavior among those exposed to the tiny amounts of widely used pesticides.

Key points for pesticides and bees

Key points

  • Bumblebees exposed to neonicotinoid insecticide have spent less time to care
  • The research contributes to the case that widely used pesticides negatively affect bees
  • Natal bees could theoretically be at greater risk of honey bees, but experts say more research is needed

A study published in the journal Science that has found bees exposed to an insecticide called imidacloprid is less likely to feed and nurture its larvae and spend more time hanging around the edge of the nest.

According to researcher and biologist at Harvard University James Crall, the most striking and confusing conclusion was that the impact on bee behavior was the strongest night.

"If you look overnight, it's totally harmful," Dr Crall said.

"It's often the majority or the entire colony [affected by imidaclorprid] they will be immobile – you never see in healthy colonies.

Imidacloprid belongs to the class of insecticides called neonicotinoids (also called "neonics", which is much easier said).

Chemically similar to nicotine, these are highly effective insecticides that interfere with the nervous system of insects.

There was a constant and bitter dispute over evidence that neon use affects bees on the ground.

This year, the European Union has announced that it will ban the external use of three insecticides in this class, including imidacloprid.

Bee barcodes

For their study, dr. Crall and the team recorded the behavior of 12 colonies of Bumbus's impatiens of bumblebee types in the laboratory, every five minutes, 12 times a day for two weeks.

They followed the movement of the bee by adding small labels on the back, marked with a number and a barcode.

"It's like a really simple KR code," said Dr. Crall, who developed computer tracking software.

Bees were allowed to feed in neighboring chambers, some of which contained a nectar carrying a pesticide.

Separated laboratory study, dr. Crall and the team also studied how pesticides were affected by colonies on the ground.

Normally, bumblebee build an outlet wax "canopy" in order to keep their holding protected from cold.

But the bees that were exposed to imidaclopride were less likely to build a canopy compared to their healthy colleagues and were less able to control the temperature of the nest.

"Unprecedented detail" in the studio

An Australian expert who also studies the effects of neonation on bees says the study provided incredible details.

"This is the first time that we have used this method to look at the impact of such a composition within this colony on the education of young people," said Andrew Barron of the University of Macquarie, who was not involved in the new research.

He said the pesticide level used in the study was small – about 10 parts per billion.

While a new study in bumblebees, Dr Barron said it was not "unreasonable" to assume that there are similar effects in other bees.

"As for neurobiology of bees and brain structure, they are all really similar," said Dr Barron.

And, he said, there will be consequences of bees that spend less time for the care of young people less survival of the larvae and slower colony growth.

"It would consist of what we saw with the effects of pesticides on honey bees and bumblebees."

Evidence of how neonates affect bees is complex, not only because the same dose of pesticides can have different effects on the same species, depending on their location.

But Dr. Barron said that this only indicates that the effects of pesticides include interaction with other factors such as the local environment.

He pointed out that most studies have shown that low doses have negative effects on the behavior of bees, including their feeding ability.

Bees under threat?

Beyond pesticides and other pollutants, bees all over the world are confronted with a variety of environmental risks, including diseases such as those that cause varroa, as well as the lack of food.

According to the authorities, the Australian bee population is not declining.

But the same can not be said for our breeding bees, says Katja Hogendoorn, an expert on behavior at the University of Adelaide, who did not take part in the study.

Native bees also play an important role in pollinating – in crops as well as in native plants.

Dr Hogendoorn said there is little research about our original bees, so we do not know if the number is increasing or decreasing.

But Dr. Hogendoorn also said that studies in the US and Europe have shown that the population of bee populations has been halved. Similar data are likely in agricultural areas in Australia due to the removal of natural vegetation as well as the use of pesticides.

More than half of bee hives do not use fodder plants, which means that the original bees in agricultural areas are at risk of malnutrition, said Dr. Hogendoorn.

While beekeepers can move their bees of bees to avoid exposure to pesticides, the inseparable bees nesting in the stems are more vulnerable.

"Native bees about 300 meters around their nest, and unlike honey, can not dilute the effects of pesticides by using it far and wide," said Dr. Hogendoorn.

Nigel Raine of the University of Guelph in Canada points to another reason why domestic bees may be at greater risk.

Although bumblebees and bees live in colonies, the effects described in the new study may be more serious in what are called "lonely bees", he wrote in a comment published in Science.

Solar bees make up more than 20,000 species of bees in the world, and most bee species of Australia.

In solitary bees, dr. Raine wrote, women are "overburdened with single mothers", who are solely responsible for raising their corruptions.

This would make it "more likely that a small change in behavior as a result of exposure to pesticides will have a measurable impact on their ability to produce as high quality as possible high quality."

Where is the neon now?

Despite the concerns of beekeepers and others in Australia, the Australian Institute of Pesticides and Veterinary Medicines (APVMA) has no plans to review the use of insecticides following a decision on a European ban.

"Given that the health condition of the Australian bee is good, there is no reason for similar restrictions," the regulator states on his website, although he will continue to oversee this issue.

The APVMA also states that research on national residues, which tested animal and plant products, found no trace of neon signs in the tested medias.

But Dr Barron says his research with CSIRO has found a negative impact on bees from neonics to just five parts per billion.

This is well below the level of 10 parts per million tested by the National Residue Survey.

As well as dr. Barron, dr. Hogendoorn argued that a more rational use of neonics is in order.

"Neonics are a very useful tool and in many cases better than other things, but they need to be very carefully used," she said.

Dr. Barron said that if a pesticide is banned and replaced with other insecticides, this does not have to be a better situation.

While not seeking an agricultural ban, Dr. Hogendoorn says that such insects should be avoided in home gardens.

This year, Australian retailers announced that they would voluntarily withdraw the sale of neon configurations to home gardeners.

Confidor's manufacturer is calling on the APVMA website, stating that neon-based products are "safe when used in accordance with the label guidelines."

But Dr. Hogendoorn said that we need results on specific research on the impact of neon use, also in combination with other pesticides, in an Australian environment.

She added that it is also important to observe the impact of such pesticides on other useful organisms in the environment, which feed on nutrients and reduce the need for spraying.

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