New ‘bee soup’ method may help in large-scale bee monitoring programmes

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Traditional methods of monitoring bees is something that is not only time consuming, but unreliable and expensive and when large-scale monitoring programmes are being considered, such an approach is not only impractical but also infeasible.

To get around this researchers have come up with a new method, which they claim is far more accurate and cheap. Researchers at University of East Anglia propose crushing up bees into a ‘DNA soup’ to help conservationists understand and even reverse their decline.

Published in journal Methods in Ecology and Evolution, the study shows that collecting wild bees, extracting their DNA, and directly reading the DNA of the resultant ‘soup’ could finally make large-scale bee monitoring programmes feasible.

This, researchers suggest, would allow conservationists to detect where and when bee species are being lost, and importantly, whether conservation interventions are working.

At a time when UK’s National Pollinator Strategy is planning a large-scale bee monitoring programme, there is a need for ways that would go beyond pinning individual bees and identifying them under a microscope as the number of bees needed to track populations reliably over the whole country makes traditional methods infeasible.

This new research, a collaborative effort of researchers from UEA and those from Conservation Grade and the University of Reading in the UK, and the Kunming Institute of Zoology and the China National GeneBank at BGI-Shenzhen in China, shows how the process could become quicker, cheaper and more accurate.

Lead researcher Prof. Douglas Yu, from UEA’s School of Biology, said that there is a need for more efficient identification methods if we scientists want to improve understanding of bee populations and their responses to conservation interventions.

“The big challenge is that there are hundreds of wild bee species per country, almost 300 in the UK alone. Even with the necessary expertise, it would be impossibly time-consuming to count and identify all the bees in each location – which is where the ‘soup’ comes in”, adds Yu.

For the research, scientists took samples of bees from different locations in the Chilterns, the Hampshire Downs and Low Weald. A total of 204 bees were extracted, and the resulting soups put through a DNA sequencer.

The scientists then used a computer program to map the raw DNA reads against the genomes of bee mitochondria, which are found in nearly every animal cell. Each bee species has a distinct genome, allowing the team to identify which species of bees had been present in each sample.

The process did not require taxonomic experts and still proved to be more accurate. Also, by skipping the DNA-amplification step known as PCR, the method was able to estimate the biomass contributed by each species, which opens the way to tracking population trajectories.

Prof. Yu said that their ‘soup’ method is a sensitive thermometer for the state of nature and large-scale bee monitoring programmes would really benefit from this type of DNA sequencing.

Yu added that their method can easily be scaled up to track more species, like the 1000 or so total pollinating insects in the UK.

Using this method researchers can find out where species diversity or abundance is highest – for example in the countryside or in city parks – and how species diversity is affected by farming methods – for example, to see if habitat set-asides support more bees.

Researchers added that species biodiversity at any given site can be revealed in a single drop of soup. It’s a technique that shaves weeks, months, years off traditional ecological methods, saves money and spares the need for tons of taxonomic expertise.