Tyler McKay | Assistant News Editor
Featured image courtesy of Pixabay
We all know how pesticides are used to kill those unwanted insects that can decimate fields of crops. However, one group of pesticides specifically is having significantly adverse and unintended effects on the surrounding environment in which they are used.
These pesticides are called neonicotinoids or neonics; they have been linked to declining populations of bees and also for facilitating what is called Colony Collapse Disorder (CCD) whereby entire bee colonies die off.
However, there is a new study that came out that links these neonics to negative effects on birds.
But first, let’s explain what neonics are and how they are used. Neonics first arrived on the agricultural scene in the 1990s, but they have now become the most common pesticide. They coat seeds and are then absorbed into the plant and protect the plant for up to 10 weeks.
They are sometimes sprayed onto the plant and have replaced the pesticides that had to be sprayed onto the plants multiple times. According to Chemistry World, “They are especially effective against sucking pests (such as aphids), but also chewing insects.”
Neonics are seen as safer than the previously used pesticides as they are more selective with the pests that they kill. Other pesticides like organochlorine and organophosporus were known to be killing mammals as well as the intended insects. Neonics have been shown to “over-excite neurons at high doses, which can lead to epileptic-like effects, cell death or nerve cell inactivation.”
A European study found that they primarily impact European honeybees, which are brought into degraded landscapes in intensive agricultural areas. They are an insecticide designed to kill insects, so bees are negatively impacted by them in addition to pest insects.
The neonics are coated on almost all corn and canola seeds in Canada and on many soybean seeds as well; they are also very widely used in and on crops in the United States.
In 2013, a study was conducted by the European Food Safety Authority (EFSA) on the effect of neonicotinoid pesticides on bees. The study found that three types of neonicotinoids impacted “bee learning and navigation and reproduction. At lower levels, normal neuronal function is impaired. It is suspected that this is how bees are harmed. After repeat exposure, target nerve cells become more vulnerable and toxicity to insects increases.” These pesticides were found in the pollen and nectar of the plants and that is why they are affecting bees.
Honey bees produce approximately 90 million pounds of honey every year and are required to pollinate some of Canada’s most profitable agricultural products. The pollination services that bees are able to provide are valued at $5.5 billion per year in Canada alone.
Additionally, bumblebees are also crucial pollinators whose services often get mistaken for those of the honey bee.
Regrettably, “We do not know very much about the status of the vast majority of Canada’s 855 native bees,” says York professor and environmental scientist Sheila Colla.
“We have the most information for the native bumblebees (42 species) and know that about one-third of these species are at risk of extinction. This is very concerning given the importance of wild bees for food production and the sustainability of native ecosystems,” Colla adds.
However, the health of bees and bee populations is affected in many different ways by many different causes. Bee populations still face trouble on account of a number of other factors including loss of habitat, disease from managed bees to wild bees, and climate change. Therefore, banning neonicotinoids alone would not be enough to revivify struggling bee populations.
Currently, there is a program in Canada and the United States to track bee populations and record statistical information. This program is called Bumble Bee Watch and is based on the photographs and input from over 8,300 people.
According to York PhD student, Victoria MacPhail, in an interview with the Toronto Star, the program is used “to figure out where are our rare species, where are our common species and how are they doing.”
MacPhail continues, “Are they doing things that change their range, are they expanding their range, contracting their range, what flowers are they feeding on, what time of year do they come out — all these basic questions about bumblebees.”
The app was designed with the intention of getting more people out in their yards and around their neighbourhoods to look for bees.
This data is key to developing successful conservation efforts as the data from Bumble Bee Watch has been able to fill in the gaps. Users of the app have been able to provide data from over 41,000 sightings of about 40 of the 46 known species.
“I’ve been working on bumblebees since 2003 and I spent a good 10 years just driving around looking for some rare species and not really finding any. So, we kind of thought maybe it makes more sense to get more eyes on the ground,” says Dr. Sheila Colla to the Toronto Star, “
As for bee conservation efforts, Colla says we need more regulation managed and privately-kept bees as well as better tracking of bee movement and bee diseases: “The current government has really stalled on protecting species at-risk. They need to move through the listing and management process more quickly.”
“Currently there hasn’t been a priority made to conserve native bee biodiversity or bees at-risk of extinction. This is very worrisome,” Colla adds.
Unfortunately, it is quite difficult to study the health of bees. The current methods can not be utilized unless the bee is already dead. This is a pressing concern as one quarter of bee colonies in Canada die each winter.
Researchers test for the presence of pathogens, toxins, and pesticides in the bees’ system. These tests take quite a long time, are expensive, and often do not paint the whole picture of what is affecting the health of the bees.
The solution to this problem may come from a project that will soon be led by York biology professor Amro Zayed. Professor Zayed is a bee genomics expert as well as a York Research Chair.
On October 1, a $10-million project will begin to develop a new health assessment and diagnosis platform. “We need to think of innovative solutions to fix the bee health crisis. The current tools are just not cutting it,” said Zayed.
These new project aims to be able to create a system whereby bee health can be studied while the bees remain alive by looking for biomarkers.
“You can identify the stressors affecting a colony, not by searching for the stressor itself, but by looking for specific signatures of stress in the bee – what we call biomarkers,” said Zayed.
“The biomarker approach has a lot of potential for quickly screening stressors affecting bees before colonies decline.”
At the completion of the project Zayed and his team hope to be able to have beekeepers send in samples of their bees for biomarker testing and then receive a detailed health report.
They will also receive a report containing management strategies for how best to support the bee colonies and improve their health.
Additionally, there is also an immediate concern relating to the use of neonic pesticides and their negative effects on migratory birds in North America.
A recent study co-authored by York professor Bridget Stutchbury found the connection. “The study originated because of my book Silence of the Songbirds (2007) where I have a chapter on pesticide effects on birds,” professor Stutchbury says.
“At the time, I was amazed when doing the background research that so few studies had been done with modern pesticides on wild birds.
“These pesticides are very harmful for pollinators (includes bees that are needed to pollinate our crops) and now we know they hurt birds too. Unfortunately for migratory birds, neonicotinoids are in heavy use in the United States and Central/South America, where our birds go during our winter.”
New blood sampling techniques were used to see how much exposure wild birds had to the neonicotinoid pesticide.
For the white-crowned sparrow, on which the study was conducted, the researchers found that 75 per cent of the wild birds had been recently exposed to the pesticide.
“Farmers and pesticide manufacturers often argue that dosing experiments are flawed because they ‘force feed’ the pesticide to bird while in the real world the planted seeds end up underground where birds can’t reach them. But our research shows wild birds are being exposed somehow,” Stutchbury says.
In the study, white-crowned sparrows were caught during a stopover on their spring migration and fed seeds coated in neonicotinoids at a higher dose than would usually be found in the wild. The birds were then tracked using “lightweight tagging technologies and a collaborative research network called the Motus Wildlife Tracking System to track the effects in the sparrows’ natural habitat.”
“The timing for this study was good because we needed a way to track birds after they were released – and now there is a large network of automated radio-receiver towers in southern Ontario that could detect our birds as they flew by on spring migration.,” Stutchbury says.
The study found the birds that were given the higher dose of the neonic lost six per cent of their body mass within six hours. That same dose was shown to affect the migration pattern of the birds.
On average, the birds stayed three and a half days longer at the stopover site before returning to their migration compared to control birds.
“Both of these results seem to be associated with the appetite suppression effect of the pesticide. The dosed birds ate less food, and it’s likely that they delayed their flight because they needed more time to recover and regain their fuel stores,” said the lead author of the paper, Dr. Margaret Eng.
Although the toxic effects of neonicotinoids were once thought to affect only insects, most notably bees, this study has shown convincing evidence that birds that are exposed to the neonic pesticide will be affected by significant negative consequences.
“Our study shows that this is bigger than the bees – birds can also be harmed by modern neonicotinoid pesticides, which should worry us all,” says Stutchbury.
Recently, an article in the CBC highlighted the devastating fact that over the past 49 years, the total bird population across the United States and Canada has dropped by a significant amount. Exposure to pesticides was found to be a contributing factor to this decline.
This new study led by conservation scientist Ken Rosenberg presents a counted loss of 2.9 billion birds compared with 1970. This number shows a shocking population decline totalling 29 per cent of all birds on the continent.
His study combines population data from more than 500 species dating back 50 years.
The study found that the significant majority of the birds that have disappeared are neither rare, vulnerable, nor endangered species. Species such as sparrows, juncos, and starlings, which are considered to be quite common, were found to have had a drastic reduction in their respective populations.
Rosenberg expected to find that some species are declining while others are growing to fill the gap left behind; however, he was shocked to find that even the most well-adapted birds like starlings have lost 83 million individuals since 1970.
In 2019, Health Canada released a statement on neonicotinoids: “To protect bees and other pollinators, Health Canada has announced that it will be cancelling some uses of these pesticides, and changing other conditions of use such as restricting the timing of application,” as traces of this pesticide have been found accumulating in water bodies and near farmland.
Populations of insects near to those farms were shown to have decreased on account of the neonicotinoid use. A decision on any policy change is expected at the end of this year.
There were also studies conducted by the European Food Safety Authority (EFSA) in 2013. These studies led to the European Union member states agreeing to ban three kinds of neonicotinoids on crops that produces flowers.
However, in 2018, the European Union decided to ban the use of neonicotinoids outside. Their use has now been restricted to indoor use such as in greenhouses.
It is clear that neonicotinoid pesticides are having a negative effect on biodiversity across North America and across the world.
They are not only affecting the bees, which pollinate crops, but they are also negatively affecting bird populations.
While some progress is being made to reduce these problems, there is still much to do.
