In many regions of the world, insects are declining at an alarming rate. However, we still know very little about the number of species currently in existence. Scientists estimate that, up to now, we have described one million out of 5.5 million insect species on Earth. Thus, it is crucial to develop reliable methods to properly monitor biodiversity.
Researchers from Lund University have discovered for the first time that it is possible to detect insect DNA in the air. By using air samples from three sites in Sweden, the scientists identified DNA from 85 species, including bees, flies, moths, beetles, wasps, and ants, as well as some vertebrate species of birds and mammals.
While traditional sampling methods use malaise traps, which lead to the death of the sampled animals, or transect walks and moth trapping, which required taxonomic expertise and generally focus on larger species of insects, a DNA metabarcoding approach can be a safer, faster, and more accurate method of investigating biodiversity.
“In the face of the biodiversity crisis, we desperately need better information on the status and distribution of species,” said study lead author Fabian Roger, an environmental scientist at the Swiss Federal Institute of Technology in Zürich (ETZ Zürich).
“Our study is a proof of concept that shows that we can detect DNA from insects and vertebrates from air collected under natural conditions. This opens many exciting possibilities for species monitoring and detection, which could allow us to comprehensively monitor biodiversity at large spatial and temporal scales.”
Although this method is still in its infancy, it has the potential of becoming a powerful tool for biodiversity monitoring. In order to refine it, a greater understanding of how DNA moves through the air is needed. Luckily, aerosol experts and meteorologist have already studied the movement of airborne particles for decades, offering thus a strong foundation for accelerating the development of DNA sampling techniques.
“We are at the very beginning of exploring airborne environmental DNA for anything other than bacteria, pollen or spores – and even there we have only scratched the surface,” said Roger. “One of the first challenges will be to optimize sampling and molecular methods to increase sensitivity and achieve more reliable detection. Then we will need to understand how airborne environmental DNA is generated, transported and degraded.”
The research will be presented at the Ecology Across Borders conference in Liverpool (12-15 December, 2021).