Researchers from the University of Trier have developed a procedure with which DNA traces of insects from dried plants can be obtained and evaluated. "We have examined commercially available teas and herbs and found in a single tea bag DNA of up to 400 different types of insects," says Henrik Krehenwinkel from the University of Trier, according to a press release. Together with colleagues, the biogeographer presented the newly developed method in the specialist magazine »Biological Letters«.
If a bee collects nectar from a flower, it leaves some saliva. A bug stings in a leaf, a spider leaves silken threads. All this is sufficient to detect the DNA of the insects, explains Krehenwinkel. Eggs or excrement are also suitable traces for the biogeographer. Whether there is a limit to what is detectable still needs to be investigated. "In principle, however, individual cells, such as a beetle, are probably enough," says Krehenwinkel.
Eruten made of dried plant material
According to the University of Trier, the innovation of the newly developed method consists in taking the environmental DNA (eDNA) not from the surfaces of the plants as usual, but from crushed, dried plant material. "Drying seems to preserve DNA particularly well," says Krehenwinkel.
So far, researchers have examined samples or caught traps if they examined which insects are on which plants. The insects die; In addition, the scientists avoid a lot of information. Because Edna is usually not available long on the plant cover because it is broken down by UV light or washed away by rain. Another restriction is that almost only insects are recorded on the surface of the plant. "Now we can also prove which insects live inside the plant," explains Krehenwinkel.
According to the researcher, the new method opens up the possibility of analyzing old plant stocks in museums and comparing their insect population with today's. "This would make it possible to find out what the insect community looked like years ago when the plant was collected, and what it looks like at the site today." This is particularly relevant in view of the insect extinction.
