Australian research has found that an insecticide may slowly contribute to bee population decline even at low doses.
A study by the University of Melbourne exposed bees to only small amounts of neonicotinoid insecticides (the most frequently used class of pesticides globally) including imidacloprid, akin to what one might expect in nature.
The insects still suffered—it lowered their energy levels, impacted their metabolism, killed brain cells, and caused blindness.
Emeritus Professor Philip Batterham said the insecticide throws off their guidance system and causes a decrease in reproductive capacity.
"We were able to attribute this oxidative stress to the binding of imidacloprid to receptors in the brain," Batterham told the AAP.
Batterham's study shed light on alternatives to insecticides, such as impeding pests' reproduction by genetic modification and the use of bacteria.
He said that all options must be on the table.
"We need to assess them all, and do the complete cost-benefit analysis and ask what is the best option in terms of crop yields and environmental health," Batterham said.
But the study noted that this was due to a lack of consensus in the data of the report of the impact on the decline of Australia's bee population.
"Information and advice available to the APVMA suggests that, in Australia, honey bee populations are not in decline and insecticides are not a highly significant issue, even though they are clearly toxic to bees if used incorrectly," the report said.
The report also noted that the biggest issues around insecticide use in Australia comes when there is a break-down in communication between the farmer and the beekeeper, resulting in a hive being exposed unnecessarily.
However, the species is under threat from other species.
Bees offer more utility than just honey to Australia.