They are in various places: on sidewalks, in gardens, in drains and, sometimes, inside our homes. To the cockroaches They are one of the most hated pests in the world and represent, for many people, a great fear, especially when they appear in the domestic environment. But, after all, what is the origin of this ubiquitous insect? A new study, published on Monday (20), may have the answers.
A searchpublished in Proceedings of the National Academy of Sciencessuggests that the german cockroach — one of the most common species worldwide and popularly known as “kitchen cockroach” — originated in South Asia, despite its name. Furthermore, researchers discovered that it may have spread around the world due to its affinity with human habitatswhich explains why we encounter these insects so often in everyday life.
The term “German cockroach” was used to name the Blattella germanica by the Swedish biologist Carl Linnaeus, who was the first scientist to describe the cockroach, back in 1776, in Europe. That’s where the hypothesis that cockroaches originated in Germany arose. However, according to the researchers of the new study, this is a mistake.
To reach this conclusion, researchers analyzed the genomes of 281 German cockroaches collected in 17 countries, including Australia, Ethiopia, Indonesia, Ukraine and the United States. From the analysis, they were able to identify similarities and differences between the genomes to estimate when and where cockroach populations might have been established.
Researchers have found that the German cockroach’s closest living relative is likely the Asian cockroach. Blattella asahinai, which can still be found in South Asia. They estimate that the Blattella germanica separated from this Asian species about 2,100 years ago.
Migration of cockroaches from South Asia to Europe and the rest of the world
Scientists believe that the German cockroach traveled west, towards the Middle East, “hitchhiking” with the commercial and military traffic of the Islamic caliphates around 1,200 years ago. After that, it may have started to spread eastward approximately 390 years ago, with the rise of European colonialism and the emergence of international trading companies such as the Dutch and British East India Companies.
About a century later, the German cockroach may have “hitchhiked” to Europe and, from there, spread around the world, according to researchers.
According to Franz Essl, an ecologist at the University of Vienna, German cockroaches were able to spread and survive to the present day due to “their extraordinary adaptability”. He explains, in an article published in Naturethat this insect is capable of quickly adapting to highly modified environments, including the urban environment occupied by humans.
Furthermore, they are “opportunistic” insects, which “makes them prone to being transported as hitchhikers to new places,” according to Essl. “This is a perfect combination of ingredients to make a species very successful in a human-shaped world.”
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