Pesticides reduce their egg-laying capabilities
Researchers found 26% of queen bumblebees treated with insecticides, stopped founding new colonies after winter hibernation. This means over a quarter of bumblebee nests are being lost every year, increasing their chances of extinction.
Pesticides affect male bees’ sperm health
Researchers found drones (male honey bees) with neonicotinoid exposure did not have reduced sperm count, but did have reduced sperm viability. Their conclusion finds that pesticides leads to queen honey bees failing to become properly fertilised and leads to premature colony failure.
Glyphosate reduces healthy gut microbiome in honey bees
Glyphosate is a very successful herbicide because it targets an enzyme usually only found in plants. However, gut bacteria in honey bees also contain this enzyme and once affected by glyphosate, increases their susceptibility to infection by disease and other pathogens.
Research has shown glyphosate leads to a weakened immune system in bees, and could be one of the causes of Colony Collapse Disorder.
Fungicides reduce beneficial fungi in Bee Bread
Honey bees use pollen to make what is known as “bee bread”. This is where they collect pollen, then mix it with a bit of nectar and some of their digestive fluids before tightly packing it into their cells where it ferments. Fermentation breaks down proteins into important vitamins such as amino acids, lactic acid, and vitamin K. Honey bees eat this because it is a source of medicine, as pollen comes from a wide range of plant sources – just as we get our vitamins from a wide range of fruit and vegetables.
But fungicide research has shown that it reduces beneficial fungi needed for bee bread fermentation, leading to inferior quality bee bread which reduces their immune system and ironically leads to more fungal disease – such as Chalkbrood.
Neonicotinoid exposure damages bees brains and affects their ability to forage
Researchers have found “rapid mitochondrial depolarization in neurons” in bumblebees exposed to neonicotinoids – meaning the plasma membrane of a muscle or nerve changes in permeability, affecting how cells transmit nerve impulses.
They found that bees suffered poor navigation, which led to poor foraging, which then led to a deficit in colony growth and contributed to bumblebee decline.