Researchers with Lund University in Sweden found that wild bee populations exposed to a class of neuro-active, nicotine-based systemic insecticides known as Neonicotinoids had a reduction in density, less reproduction and colonies that did not experience growth.
The “Neonics” are a class of pesticides which have previously been linked to declines in bee populations. They were developed in 1991 and commercial use began in the mid-1990s. Around 2006 commercial beekeepers began reporting what has become known as colony collapse disorder— entire colonies of bees died off with no obvious cause. The disorder has been reported in commercial colonies all over the world. Several studies have implicated Neonics, which are used to kill insects harmful to crops.
The Swedish scientists conducted the study in the wild, the first of its kind. They examined 16 patches of land with canola seeds, half of which were sprayed with the pesticide and the other half which were not sprayed. The researchers found that wild bees displayed negative health effects while honeybee populations, which pollinate crops with assistance from humans, did not display the illness. A second study found that in laboratory tests bees are not deterred by the pesticide but may in fact prefer crops sprayed with the chemicals. This could indicate an addiction to the nicotine in the pesticides. Both studies were published in the journal Nature.
The study’s lead author Maj Rundlof said the reduction in bee health was “more dramatic than I ever expected. Rundlof told Reuters that the bees sprayed with the pesticide also had not gained any significant weight when compared to the normal colonies.
David Fischer, director of pollinator safety for neonicotinoid manufacturer Bayer CropScience, said the study was faulty, accusing Rundlof and her team of using “an overdose” of the pesticide. However, Rundlof said the dosages used came from recommendations in Bayer CropScience documents.
Although Rundlof’s study marks the first time the effects of Neonics on bees in the wild were analyzed, the pesticides have previously been linked to a number of health issues for the bee population.
In July 2014 Dutch researchers published a study in the journal Nature which found a strong correlation between pesticides measured in surface freshwater and lower population growth rates of 14 species of birds in the Netherlands. The study suggests the bird population may be drinking infected water or feeding their offspring infected insects.
Twenty nine scientists from four continents spent five years researching eight hundred published studies that examined the effect of Neonics on ecosystems that support food production and wildlife. Their research was published in the journal Environment Science and Pollution Research. The Worldwide Integrated Assessment of the Impact of Systemic Pesticides on Biodiversity and Ecosystems (WIA) was produced by Task Force on Systemic Pesticides. The Task Force was formed in response to concerns about the impact of systemic pesticides on biodiversity and ecosystems. ”
The team said their study was, “the single most comprehensive study of Neonics ever undertaken”. The scientists research found that the Neonics are as great a risk to the environment as the previously banned DDT. In some cases the effects were found to be 5,000 to 10,000 times more toxic to bees than DDT.