GM Free Cymru

Glyphosate screws up honeybee navigation

Date Added to website 9th August 2015

Glyphosate screws up honeybee navigation

Comment: This is a very important paper, with findings that confirm something raised many years ago in conferences and presentations associated with GMOs and the agrichemicals that go with them. We remember a conference, maybe ten years ago, at which there was much discussion about findings (in Germany?) that suggested honeybees in the vicinity of GMO crops were losing their ability to navigate back to their hives, and were getting lost -- with dramatic losses then being suffered by previously viable hives. The evidence just stacks up, day by day, that glyphosate is a seriously nasty chemical. It is, after all, marketed by Monsanto as "the ultimate killing machine"........

Balbuena, M. S., Tison, L., Hahn, M. L., Greggers, U., Menzel, R., & Farina, W. M. (2015). Effects of sub-lethal doses of glyphosate on honeybee navigation. The Journal of experimental biology, dev-117291.


Glyphosate (GLY) is a herbicide that is widely used in agriculture for weed control. Although reports about the impact of GLY in snails, crustaceans and amphibians exist, few studies have investigated its sub-lethal effects in non-target organisms such as the honeybee Apis mellifera, the main pollen vector in commercial crops. Here, we tested whether exposure to three sub-lethal concentrations of GLY (2.5, 5 and 10 mg/L corresponding to 0.125, 0.250 and 0.500 µg/animal) affects the homeward flight path of honeybees in an open field. We performed an experiment in which forager honeybees were trained to an artificial feeder, and then captured, fed with sugar solution containing GLY traces and released from a novel site (the release site, RS) either once or twice. Their homeward trajectories were tracked using harmonic radar technology. We found that honeybees that had been fed with solution containing 10 mg/L GLY spent more time performing homeward flights than control bees or bees treated with lower GLY concentrations. They also performed more indirect homing flights. Moreover, the proportion of direct homeward flights performed after a second release at the RS increased in control bees but not in treated bees. These results suggest that, in honeybees, exposure to GLY doses commonly found in agricultural settings impairs the cognitive capacities needed to retrieve and integrate spatial information for a successful return to the hive. Therefore, honeybee navigation is affected by ingesting traces of the most widely used herbicide worldwide, with potential long-term negative consequences for colony foraging success.