The Effects Of Glyphosate On Honeybees

Glyphosate or Roundup is the mostly commonly used herbicide in the world. A Monsanto scientist discovered the chemical in 1976, and its use has risen dramatically over time. This is in part due to the introduction of Roundup ready seeds in 1996. Glyphosate has increased from 5.7 million kilograms in 1990 to 125 million kilograms in 2014 (Benbrook 2016). Honeybee hives have also decreased over this period from approximately 3 million in 1992 to 2.5 million in 2011 (Monsanto & HBAC 2014). Honeybees pollinate many crops around the world, which leads to increased increase food production. With the deaths of honeybees come many complications. Pimentel (2005) calculates that the use of pesticides creates a 286 million dollar loss in the United States, …show more content…
Balbuena et al. (2015) perform a catch and release experiment to determine the effect of glyphosate on honeybees. The bees ate 10mg/L, 5mg/L, and 2.5mg/L of glyphosate. Exposure to glyphosate slows the bees’ return trip to the hive. Flight paths are also affected. Bees fed with the higher concentrations took more time returning to the hive and had more indirect flights. The bees that ate 2.5mg/L and 5mg/L had indirect flights after the first release, but had normal flights after second. This affects their homing behavior. Memory retrieval is impaired because the probability of bees taking a shorter route to the hive is lower, therefore, longer flights and lack of improved homing behavior is increased. Exposure to glyphosate at non-lethal levels cause sublethal effects and, in turn, changes bees’ foraging behavior.
Another study by Frazier et al. (2015) looks at the effects of pesticides on foraging bees. They calculate 53 different pesticide residues on 8 crops and number of dead and dying bees. Frazier et al. (2015) finds a decrease in number of forager bees in cotton. Fungicide levels are higher than insecticides. The bees collect residues beyond target crop. The author concludes bees are in coming into contact with agrochemicals. Bee deaths are highest in cotton, pumpkin and

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