A single green tea bag could contain up to 400 different species of insects . This is what a team of scientists from the University of Trier in Germany found while conducting a study on samples of teas and dried herbs purchased from German food stores.
Living beings leave more or less visible traces of our presence wherever we pass. These traces include secretions such as saliva, debris, and even dead skin cells, many of which contain our DNA. Insects are no exception. Spiders , beetles and other invertebrates leave traces of their existence , also on the tea leaves that, while growing, they may have bitten or even simply rubbed.
Now, in a new study published in Biology Letters , scientists have just detected evidence of no more and no less than 1,200 different species of invertebrates in just 40 samples of teas and dried herbs . “What really surprised me was the great diversity we detected,” Trier University ecological geneticist Henrik Krehenwinkel told The Scientist . “We found in green tea up to 400 species of insects in a single tea bag.”
In total, the researchers found traces of 3,264 invertebrates in samples of tea and other commercial herbs purchased from German grocery stores, including predators, herbivores, detritivores (they feed on detritus or decaying organic matter), and parasites. of all the world. There were traces of DNA from spiders, cockroaches, mites, flies, butterflies, praying mantises and many more.
Krehenwinkel and his team suspect that this amazing diversity is due to the way dried herbs, such as tea leaves, mint and parsley, are processed. What happens is that grinding them grinds up the DNA of everything around the plant in the field , including some whole insects and their eggs. The result of the grinding is mixed and spread throughout the batch.
The resulting environmental DNA (eDNA) provides valuable information to researchers as it can be used to locate the place where plants are grown and shows the status of the invertebrate biodiversity present in the area. “Dried plant material appears well suited as a novel tool for monitoring arthropods and arthropod-plant interactions, detecting agricultural pests, and identifying the geographic origin of imported plant material,” the team write in their paper.
Despite what has been said, scientists are not throwing bells on the wing and it is just as they point out in the publication: “Although our electronic DNA method represents an important advance for the monitoring of arthropods, it should be noted that it is not free from bias and will require further standardization in the future. In this sense, the researchers are not clear whether the method used would not detect certain species that, although they are frequent in the environment, leave less of a genetic trace in these plants.
Still, it is clear that this method provides more information than we were getting before and could be used to simplify environmental monitoring and possibly even help extend species records over time , using herbarium specimens from museums. .
Insects and other invertebrates are essential for life, as they are part of our life support system: the natural environment. It would be excellent news if records of reading tea leaves were obtained.
Reference:
Krehenwinkel H, Weber S, Künzel, S y Kennedy, S. 2022. The bug in a teacup—monitoring arthropod–plant associations with environmental DNA from dried plant material. Biology Letters. DOI: https://doi.org/10.1098/rsbl.2022.0091
