United States – Pesticides used by farmers have been acting as bee’s birth control, which may help explain the massive decline in bee’s populations.
Almost everybody knows that currently bees are dying and it has to do lot with the pesticides men use. But it was not clear exactly what the pesticides did.
Now, a new study published on July 26, 2016, may have the answer. A team of researchers was led by Geoff Williams, a bee researcher at the University of Bern in Switzerland and according to their findings, the pesticide more commonly used acts as ‘birth control’ for male bees.
Studying the male bees, so often ignored, was a turning point in the investigation. The male bees are known as ‘drones’, and their only purpose is to mate with a queen, to create more workers.
However, as it can be easily seen, it is a critical purpose. Lack or poor mating can decline the colony’s population and in the end, cause its elimination.
As it happens, drones exposed to neonicotinoid insecticides (the most common pesticide in the world) produce fewer sperm cells than unexposed males, which takes its toll in their ability to procreate.
The team focused solely on the drones, exposing them to two pesticides that are being reviewed in the European Union, precisely because of bee’s decline, clothianidin, and thiamethoxam.
The amount used was the same bees could find in nature’s flower pollen. The results stated that the drones exposed had sperm viability 8 to 11 percent lower, and 39 percent less living sperm, compared to the unexposed drones.
A big number of bees have died in the last years
In the last decade, honey bees have been dying, American and European beekeepers have denounced declines of thirty percent in their hives per year. A study conducted between beekeepers in the United States discovered that in a period of a year, almost half of the bees colonies had died.
But they are not the only ones. Scientists have also found that Monarch butterflies and bumblebees are dying in huge numbers.
This has many causes, from habitat loss to parasites. However, the indiscriminate use of pesticides in the hands of farmers may be one of the most important elements for the decline in the different pollinators’ populations.
According to Dennis van Engelsdorp, a bee researcher at the University of Maryland, stated that neonicotinoids, which are the most commonly used pesticides, also carry ‘sub-lethal’ effects.
“We’re beginning to find that these exposures may be hurting and slowing down colonies in more insidious ways”, he claimed.
Should the authorities just ban neonicotinoids?
The problem is not that easy. Dave Shutler, an ecologist at Acadia University in Nova Scotia, has been studying the number of pesticides bees are exposed to, while looking nectar and honey. The discovery was astonishing: Over thirty different insecticides were found inside the beehives, in pollen that was stored.
Honeybees are hugely important for human survival. They alone pollinate 70 percent of the food crops grown by humans. The honey beekeepers produce and the pollination of this crops not only is valued at billions of dollars, but it also means plants keep growing to be eaten by either humans or the herbivores humans will later consume.
Without the humble honeybees, humanity will face a food crisis of unknown precedents.
Sources: National Geographic