Tackling mosquitoes and protecting bees

06 August 2021 | Muriel Cozier

‘The regulatory process in its current form does not protect bees from the unwanted consequences of complex agrochemical exposure.’

Researchers in Australia have begun a three year project that will use genomic sequencing to develop strategies to suppress the Aedes vigilax mosquito. The insect spreads the so called Ross River virus, the most reported mosquito borne disease in Australia, with more than 4000 cases reported each year.

The work will be carried out by the University of Newcastle, CSIRO, the NSW Department of Health and the University of Melbourne. The project is part of the University of Newcastle’s Grand Challenge 2020, to reduce the burden that mosquitoes pose to human health.

The research team said that advances in genomic sequencing meant that very small amounts of DNA could be sequenced to track genetic differences of individual mosquito genomes and find distinct populations – a technique which has not been applied to this species before. The study will help inform decisions on controlling the mosquito population.

Meanwhile, researchers from Royal Holloway, University of London, UK, have found that bees exposed to a combination pesticides, parasites and poor nutrition had higher rates of mortality than would be predicted from their combined impact. In particular, exposure to multiple agrochemicals was more likely to increase bee mortality than other stressors.

The researchers say that the findings, which have been published in the journal Nature1, confirm that exposure to combined stressors can have a far more harmful impact on bees than current environmental risk assessments predicts.

Dr Harry Siviter, joint first author on the paper and formerly of the Department of Biological Sciences at Royal Holloway, now at the University of Texas, Austin, US said: ‘Crops are treated with multiple agrochemicals, so bees are routinely exposed to several different chemicals simultaneously. Our analysis found that the interactions between these chemicals significantly increased bee mortality, beyond the levels we would predict if we just added the negative impact of multiple chemicals together. These interactions are not considered when agrochemicals are licensed for use, and so their impact on bees will be underestimated.’

The research team concludes that regulators and producers of agrochemicals must fundamentally change their approach to risk assessment. ‘The regulatory process in its current form does not protect bees from the unwanted consequences of complex agrochemical exposure,’ the researchers said.

1 DOI:10.1038/s41586-021-03787-7

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