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Researchers use fly faeces to get insight into Singapore's biodiversity
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The genetic material of the critically endangered Sunda pangolin (left) and Raffles' banded langur can be detected in fly excreta.
PHOTOS: LIANHE ZAOBAO,SABRINA JABBAR
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SINGAPORE - Most people detest flies, so their faecal matter and vomit would be even more unappealing.
But a group of scientists have found that there is value in the waste of certain faeces and flesh-eating flies.
Researchers from the National University of Singapore (NUS) and Berlin’s Natural History Museum in Germany have found that the genetic material of the critically endangered Sunda pangolin and Raffles’ banded langur can be detected in fly excreta.
This paves the way for a low-cost, non-invasive way of surveying the diversity of wildlife in nature areas.
Their method, used in a study whose report was published on online archive bioRxiv in August, recorded 20 species of animals, including birds and reptiles, in the Nee Soon swamp forest using DNA signals found in excreta of about 400 flies.
Currently, the analysis of invertebrate-derived DNA (iDNA) – vertebrate DNA that is sourced from invertebrates (with no backbone), including mosquitoes and leeches – is used mainly to monitor mammals.
Biologist Rudolf Meier, who co-authored the study, said: “The advantage of flies is that they respond to any carcass and any dung that is nutritious. It could be a lizard dying behind some tree and flies will still be interested.”
But the traditional method of extracting DNA from the guts of flies is often an expensive, time-consuming process that involves dissecting each specimen, he noted.
“For me, biodiversity surveys have to use techniques that can be done by many people at low cost, because otherwise you cannot gather enough information,” said Professor Meier, who heads the Centre for Integrative Biodiversity Discovery at Berlin’s Natural History Museum.
So the scientists turned to fly faeces and food that they regurgitate.
But a group of scientists have found that there is value in the waste of certain faeces and flesh-eating flies.
Researchers from the National University of Singapore (NUS) and Berlin’s Natural History Museum in Germany have found that the genetic material of the critically endangered Sunda pangolin and Raffles’ banded langur can be detected in fly excreta.
This paves the way for a low-cost, non-invasive way of surveying the diversity of wildlife in nature areas.
Their method, used in a study whose report was published on online archive bioRxiv in August, recorded 20 species of animals, including birds and reptiles, in the Nee Soon swamp forest using DNA signals found in excreta of about 400 flies.
Currently, the analysis of invertebrate-derived DNA (iDNA) – vertebrate DNA that is sourced from invertebrates (with no backbone), including mosquitoes and leeches – is used mainly to monitor mammals.
Biologist Rudolf Meier, who co-authored the study, said: “The advantage of flies is that they respond to any carcass and any dung that is nutritious. It could be a lizard dying behind some tree and flies will still be interested.”
But the traditional method of extracting DNA from the guts of flies is often an expensive, time-consuming process that involves dissecting each specimen, he noted.
“For me, biodiversity surveys have to use techniques that can be done by many people at low cost, because otherwise you cannot gather enough information,” said Professor Meier, who heads the Centre for Integrative Biodiversity Discovery at Berlin’s Natural History Museum.
So the scientists turned to fly faeces and food that they regurgitate.
The researchers trialled a simplified technique, which gets the flies to naturally excrete their digestive fluids before dissolving the excreta in water and sequencing its DNA.
Their study found that nanopore DNA sequencing, a technique that can be used in a field station to get genetic information in real time, can reduce the time needed to obtain data if the target species can be matched with publicly available databases.
During their survey of Singapore’s largest swamp forest in Nee Soon between May and July, the researchers also discovered that collecting flies near a road yielded similar results to collecting insects from deeper in the forest.
Their study found that nanopore DNA sequencing, a technique that can be used in a field station to get genetic information in real time, can reduce the time needed to obtain data if the target species can be matched with publicly available databases.
During their survey of Singapore’s largest swamp forest in Nee Soon between May and July, the researchers also discovered that collecting flies near a road yielded similar results to collecting insects from deeper in the forest.
