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.
The findings contradict an early 2014 report from the Australian Pesticides and Veterinary Medicines Authority, which concluded that the impact of neonicotinoid is not as significant as in Europe or North America.
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.
Unlike in other countries, and because of Australia’s unique ecosystem, scientific analysis of our bee populations indicates that the species are not in decline in Australia. Australia has 2,000 different species of native bees and according to data from the department of primary industries, 668,672 honeybee hives.
However, the species is under threat from other species.
The Varroa destructor, a tiny parasitic mite that feeds on the blood of bees, has instead been described as ‘the most serious threat’ to the viability of the Australian bee industry.
Bees offer more utility than just honey to Australia.
Most of the world’s food crops depend on bee pollination, including fruits and high-value products that keep Australia running such as coffee and cocoa. It is estimated that honey bees offer Australia up to $6 billion a year in pollination services.