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| Asian Needle Ant |
A research team led by experts from the Institute of Evolutionary Biology (IBE: CSIC-UPF), in Barcelona, has identified for the first time in Europe an individual of the Asian needle ant ( Brachyponera chinensis ), a highly invasive species. The team has used the DNA barcoding method to genetically identify the male of the species, found in a coastal municipality of Naples.
In recent years, the presence of various species of exotic ants has been detected in Europe , but in the case of B. chinensis , experts warn of elements of special concern.
"If it consolidates its presence in the territory, the invasion of the Asian needle ant could threaten native ant populations and alter the ecosystems of European natural and urban habitats," highlights the IBE in an informative note on the work led by its researchers.
The authors highlight, as an important threatening factor, that "the establishment of B. chinensis in urban areas could constitute a public health problem, given the documented reaction caused by the poison injected by this ant."
The results of the investigation in which the first detection of this species in Europe has been confirmed have been published in the journal Zootaxa .
Invasive alien species are considered one of the main causes of the current biodiversity crisis. In recent years, humans have introduced 200 species of ants outside their natural range and some of them have become invasive. This is the case of the Asian needle ant, Brachyponera chinensis, which has undergone an impressive expansion of its range in the last 80 years.
Its natural distribution includes coastal regions of mainland China, Taiwan, the Korean peninsula and Japan, while in the 1930s it was introduced to the United States of America (USA), where it has established itself and is now present in 17 state. In the North American territory, B. chinensis invades native forest habitats and has had a strong negative effect on most native ant species. Additionally, due to its sting and the properties of the venom it injects, B. chinensis has been identified as an emerging public health threat in the US, causing significant allergic reactions.
First known specimen in Europe
One of the authors of the new study and an amateur entomologist, Vincenzo Gentile, collected an unidentified male of the genus Brachyponera that was attracted to the light of a street lamp on July 3, 2020 in Torre Annunziata (Naples, Italy), in a residential area. approximately 1 km from the city port.
The morphological characteristics of the specimen and the subsequent genetic analysis confirmed that it was the first specimen of Brachyponera chinensis identified in European territory.
A first morphological investigation revealed that the invasive ant did not belong to any of the most frequent invasive families – Formicinae, Dolichoderinae and Myrmicinae subfamilies-, but rather belonged to the Ponerinae subfamily, of mostly predatory ants. However, the identified specimen – in particular of the genus Brachyponera – was different from any native Euro-Mediterranean posture.
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The subsequent genetic analysis, carried out by INPhINIT ”la Caixa” predoctoral researcher Mattia Menchetti in the IBE Butterfly Diversity and Evolution laboratory, led by lead researcher Roger Vila, confirmed that it was a male Brachyponera . chinensis . The study suggests that its origin is possibly the USA, or that the invasive species has been introduced to both continents from the same place of origin.
“Genetic barcoding, also known as DNA barcoding, is a very useful tool. It involves using a short DNA sequence as a barcode specific to each species. In this way, we can identify any sample, which is useful both in basic science and in the control of invasive species, pests, the illegal trade of species, in forensic analysis, etc.”, explains Menchetti.
The nest of origin may be in private areas that are difficult to
access and the colony – or colonies – may have time to spread
undetected
Like many other soil invertebrates, ants are often accidentally introduced to new environments due to globalization and in particular the plant trade. Their frequent introduction into private gardens makes it difficult to detect these species in their early stages, before they spread over a wide region, as is the case with B. chinensis in Torre Annunziata. Although the ants of the city of Naples had been studied between 2016 and 2021, no other individuals of this species had been found.
The fact of having collected a flying male, in the process of swarming, suggests that at least one nest is already in an advanced stage after the introduction. “The nest of origin may be in private areas that are difficult to access and the colony – or colonies – may have time to spread without being detected”, adds Mattia Menchetti. "However, it cannot be ruled out that a queenless colony was introduced and that the males were produced by the worker ants, an exceptional but possible occurrence for B. chinensis ."
The Mediterranean basin is home to a growing number of exotic species, but most have been confined to the interior of buildings and greenhouses, or in urban settings. However, the expansion of B. chinensis into US forest habitats suggests that this species could invade European natural habitats, particularly forests, with potential negative effects on native ant communities and ecosystem health.
Ecological and health problems
“This is an invasive species that is causing important ecological and health problems in the United States and that in Europe could have effects comparable to those of the Asian hornet or the Argentine ant. Experience tells us that, once the exponential phase of expansion of an invasive species has arrived, we do not have the tools to eradicate it and, at most, we can control it by investing enormous amounts of public resources, so we must take advantage of the window of opportunity which represents the so-called latency phase; the time during which the invasive species consolidates in the new place and is still very localized” , explains Roger Vila.
With experiences like the current one, Roger Vila proposes «rethinking the control strategy of invasive species and redirecting resources towards biomonitoring, which allows early detection, and a body of officials for immediate action as soon as the alarm goes off of a new introduction ».
In the specific case now detected, Mattia Menchetti indicates that the experts "call for action at this early stage of the new biological invasion and propose that a detailed survey of a large area around Torre Annunziata be carried out."
scientific collaboration
This research has received the support of the ”la Caixa” Foundation, among others. The Institute of Evolutionary Biology (IBE) is a mixed institute of Pompeu Fabra University (UPF) and the Higher Council for Scientific Research (CSIC) founded in 2008 in Barcelona.
IBE researchers study the processes and mechanisms that generate biodiversity, and their lines of research cover topics such as genetic and molecular evolution, population biology, the biology of complex systems and the recovery of ancient DNA. The institute has more than one hundred and twenty workers, who are distributed between two neighboring buildings: the Barcelona Biomedical Research Park (PRBB) and the Mediterranean Center for Marine and Environmental Research (CMIMA).
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