image of Order:Hymenoptera Family:Formicidae Genus:Pachycondyla Species:Pachycondyla chinensis Specimen:casent0104738 View:profile

Invasive Asian needle ant found in Europe, threatens biodiversity

Invasive exotic species are considered one of the main causes of the current biodiversity crisis.

Invasive exotic species are considered one of the main causes of the current biodiversity crisis. In recent years, humans have introduced 200 species of ant from outside of their natural area of distribution and some of them have become invasive. The global exotic pet trade and global plant trade have aided in the transport of such insects. This carries various pros and cons, and has even recently speculated to help aid the climate crisis. Such is not the case of the Asian needle ant, Brachyponera chinensis, which has seen its area of distribution greatly expand in the last 80 years.

Origins of the Asian needle ant

The Asian needle ant has seen decades of distribution, naturally originating in regions of China, Japan, the Korean peninsula, and Taiwan. The ant went on to invade the United States during the 1930s, where one can find B. Chinensis in 17 states today. The common denominator for the Asian needle ant is its negative effect and presence on other ants in the areas of invasion because of the poison it contains can kill other insects upon biting. For humans, the bite also causes a painful allergic reaction, which has become a public health concern due to rising allergic episodes where the ant is present.

Asian needle ant discovered in Europe

A team led by the Institute of Evolutionary Biology (IBE) – a joint venture between Consejo Superior de Investigaciones Científicas (CSIC) and Pompeu Fabra University (UPF) in Barcelona – shared findings of the inaugural finding of the Asian needle ant in the European region. The ant identified was a male, drawn to a light source within a residential area of Naples, Italy in early July. After evaluation and genetic analysis were performed, findings revealed that the identification of B. Chinensis was correct and the first of its kind on European soil.

Something that makes B. Chinensis different is how its morphological results showed that this invasive species varied from the other invasive groups in the region, including Dolichoderinae, Formicinae, and Myrmicinae divisions. Instead, the Asian needle ant belonged to Ponerinae, notably known for containing predatory ants, despite the genus Brachyponera isolating from any native European-Mediterranian types of its kind. While your typical guide to Europe may include sightseeing, transportation and landmarks, the Asian needle ant may be the newest, albeit unwanted, attraction on your list according to scientists who verified its presence in the area. 

The confirmation of the male ant was the result of genetic analysis by INPhINIT researcher Mattia Menchetti at the Butterfly Diversity and Evolution Laboratory – part of the IBE, who theorised that the origin could be from the United States, or that the ant has come to both the European and North American continents from and same location of origin. The ant collected was also a flying male, indicating the process of swarming and the presence of a nest in its advanced stages. According to Menchetti, the source of the nest could be anywhere from hard-to-reach areas, or within colonies that are hard to find – giving time for the insects to multiply while remaining unseen.

Menchetti shares that genetic barcode – also referred to as DNA barcoding – is a helpful asset to search for a specific species, allowing for DNA sequences to act similarly to a unique barcodes, identifying samples gathered.

Trade facilitates the spread of foreign species

Ants are frequently introduced to new environments via plant trading and globalization. The movement and growth of the plant trade into private gardens shields the discovery of the insects at early stages of development, so when they are spread, the discovery of the invasion is somewhat of a surprise. This is also the case for Brachyponera chinensis.

Stopping invasive species is a growing challenge

The issue with invasive species, especially ones like B. Chinensis, is the problems they create for both public health and their new ecosystems. In urban areas, the public health crisis is particularly evident, which highlights the importance of regulation and identification of invasive species closer to their arrival date. The USDA Forest Service has confirmed that there is a heightened presence of these insects. Once an invasive species expands into an ecosystem, we cannot get rid of it without an immeasurable number of resources and materials, making the latency phase in invasion a key factor in avoiding large-scale ecological disruption. Some regions have turned to a small virus to fight invasive insect types, such as an Atlanta-based trial to combat invasive fire ants in the region, but most scientists agree that stopping invasion in the latency phase is key.

The latency phase is defined as the period it takes for the invasive species to become established in the new place, making it localized. Roger Vila, a lead investigator who was involved with the genetic analysis of B. Chinensis, explained that the method of controlling invasive species types would require us to “redirect resources towards biomonitoring” – something that will lead to upfront identification and result in a response team just as those species are identified. It is still unknown how fast this species will spread throughout Europe and threaten native ecosystems across the continent.

Marleena Garris

Marleena Garris is a reporter at Breakthrough.

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