German biologists have shown that traces of hundreds of species of insects that were once in contact with the plant can be found in one single tea bag, reports Naked Science.
Insects are not part of the traditional cuisine of the peoples of Europe and Russia. However, local residents involuntarily and constantly eat them – including along with the most popular hot drink. German biologists have analyzed “environmental” DNA (environmental DNA, eDNA), trace amounts of which are contained in regular tea bags. They managed to find the genes of thousands of species of insects, and in each individual bag – hundreds. Scientists write about this in an article published in the new issue of the journal Biology Letters.
eDNA, which can be isolated from a variety of environmental objects, serves as a convenient tool for monitoring local ecosystems. It can even be caught from the air in order, for example, to find out the species composition of local insects, to determine the presence of certain rodents in a hole, or even people in a room. In a new study, Henrik Krehenwinkel and colleagues at the University of Trier in Germany found eDNA in regular tea bags.
Indeed, in order for the DNA of an insect to remain on a leaf, sometimes it is enough for an insect to gnaw on it. DNA is quickly destroyed by ultraviolet light in the open sun and is easily washed off with water, but crushed tea leaves can retain it for a long time, until the moment when the DNA enters the cup. Scientists were convinced of this by discovering that in addition to 100-150 milligrams of tea, in a bag bought at a nearby store, there are DNA fragments left by hundreds (up to 400) species of insects. In the entire set of samples, traces of already thousands of species have been identified.
Henrik Krehenwinkel himself admits that he prefers coffee to tea, and coffee beans are roasted, during which any DNA breaks down. However, the task of the authors was not to demonstrate the “contamination” of tea. They are confident that a similar approach will allow us to analyze plant samples that are preserved in old herbariums and find out by eDNA which insects surrounded them then. The same work can be done for modern plants in the field. These “evidence” will help to find out the composition of communities associated with different plants and ecosystems, and track their changes over time.
