Insects are among the most numerous and abundant animals in the world, and many of them belong to so-called alien species that have spread beyond their specific natural environment of origin. However, not everyone knows that it is one of the most invasive species European insects, as explained in an article published in the journal Neobiota. In fact, these insects have spread to almost every other continent and caused billions of dollars in damage to the world economy.
In Europe and Italy, it is little talked about because these species belong to our ecosystems and do not cause much damage, as fire ants or other animals from geographical contexts very distant from ours can do. In other parts of the world, these insects are known to be among the main culprits collapse of local biodiversity and conservation biologists are constantly trying to keep them at bay so they don’t cause more serious damage.
Among the most affected areas are North Africa, the Arabian Peninsula, Australia, various archipelagos in the Atlantic and Pacific, New Zealand, and Central and North America. Among the most feared insects are ants, beetles, moths and even wasps and small tisanuras, also known as silverflies.
Looking at the list of European species capable of conquering other continents, the question spontaneously arises as to how they managed to settle in other territories, given that most have perfectly adapted to the European continental climate, different from those of other continents. However, as one of the authors of the study explains to us – Rylee Isitt of the University of New Brunswick in Canada – we must not be fooled by the extreme climatic conditions with which these insects have had to deal: many species that have arrived on other continents are actually able to adapt to many climatic conditions and have found ecological niches that in some ways resemble their habitat of European origin.
But how did these insects manage to get to other continents? «Simple – Isitt said in a comment shortly after the article was published – Like everyone else: traveling together with a person».
The model proposed by the Canadian professor is quite simple and also takes into account the direct effect of human diffusion of the species. Taking into account the international trade routes that had developed since the second half of the sixteenth century, shortly after the discovery of America and the introduction of the Atlantic slave trade, Isitt succeeded track the arrival of European species to the rest of the world, although not always accurately. In fact, several years pass between the arrival of a species in a new territory and its direct observation by a person who is able to identify it, especially in a complex context such as the first colonial empires in which indigenous people were persecuted. there were few people educated to study the local flora and fauna.
To solve this problem and clarify once and for all the history of the invasion of European species, the researchers also tried another approach that cannot be accused of inaccuracy: they tried old bills of lading that were present in sea shipments. These connected the new colonial cities with the countries of origin of the European population and made it possible to obtain the dates of departure and arrival of goods with maximum accuracy.
“The study of the ancient transportation system was very important for our research, as it allowed us to develop a new theory that explained the massive arrival of European species to other territories,” explained the researchers. Among the goods most present in these shipments was plants and large containers of soiluseful for fertilizing the arid soil of some non-European regions and, according to Isitt, the abundance of these elements helped insects from our territories to spread to the world.
Once the settlers landed, they spread their wares over a large area and indirectly spread large numbers of “exotic” animals, including through horticulture and agriculture. Introduced plants could too they provided suitable food and habitat for the subsequent arrivals of non-native insects that would otherwise not be able to find something to eat because they would not be adapted to the native flora. Thus, populations of insects of European origin began to increase worldwide, creating a real paradox for science.
This research is also very useful for understanding the ways in which insects spread in the past, compared to current ways that allow insects to travel even by plane and reach very isolated areas once inaccessible to the species.