First Record of Invasive Electric Ant in Canary Islands Reveals Genetic Divergence

Researchers have documented the first confirmed presence of *Wasmannia auropunctata*, commonly known as the ‘little fire ant’ or ‘electric ant,’ within the Canary Islands, an important discovery that highlights the escalating threat of invasive alien species (IAS) in the Western Palearctic. The initial detection occurred in August 2023 within the interior of a golf course and the surrounding gardens on the island of Tenerife, located in the southern part of the archipelago. This finding, which expands the known distribution of this highly aggressive species, was confirmed through a rigorous combination of morphological identification and advanced molecular barcoding techniques. The study provides critical data on the population structure and genetic makeup of this newly recorded group, revealing significant divergence from other established populations, such as those found in Málaga on the mainland of Spain. This genetic separation strongly suggests that the western Palearctic has been colonized by *W. auropunctata* through at least two independent invasion events, a finding that has major implications for understanding the dispersal patterns and future spread of this formidable species.

The threat posed by *Wasmannia auropunctata* is recognized globally due to its intrinsic biological characteristics and its low detectability, making it one of the worst invasive ant species worldwide. This species, which is native to South and Central America, has expanded its range to encompass at least 31 countries and islands, primarily within tropical and subtropical regions. Its invasive success is attributed to a confluence of traits, including a generalist diet, the ability to establish itself in diverse habitat types, and a highly successful supercolonial social structure. Furthermore, its invasive populations exhibit polygyny and clonal reproduction, which are key factors in its ability to thrive in human-modified environments. *W. auropunctata* is considered an extremely serious socioeconomic threat, ranking as the second ant species with the highest reported economic costs worldwide, estimated at US$ 7.35 billion. This species is also listed in the IUCN Global Invasive Species Database (GISD) and is recognized as a species of concern by the European Union, underscoring the severity of its ecological and economic impact.

The ecological consequences of *W. auropunctata* are severe, as it has been reported to displace native ant species, reduce the populations of various invertebrates, and even harm wild and domestic vertebrates and humans. In the context of the Canary Islands, this is particularly alarming because the archipelago is a biodiversity hotspot within the Mediterranean basin, with Macaronesia—which includes the Canary Islands—contributing significantly to the unique species count of this region. The Canary Islands themselves are highly vulnerable, with 40.3% of its fauna and 22.4% of its flora being endemic. The detection of *W. auropunctata* in this sensitive environment poses a significant risk to the endemic myrmecofauna, which currently includes 61 ant species and subspecies, 19 of which are endemic. The early detection of this species in a limited area, such as the golf course and adjacent gardens in Tenerife, provides a crucial temporal window for potential eradication efforts before its dispersal to other parts of the island or the wider archipelago can occur.

The scientific investigation into this new population involved meticulous morphological and molecular identification processes. Morphological examination was conducted using a Zeiss Stemi 2000 stereomicroscope, with species-level identification supported by taxonomic keys and Antweb images. The workers of *Wasmannia auropunctata* were described by several distinctive features: they are small ants, measuring 1–2 mm in total length, and are monomorphic. Key diagnostic features include pronounced frontal carinae that extend to the back of the head and form prominent antennal scrobes, antennae composed of 11 segments with a 2-segment apical club, large propodeal spines, and a convex mesosoma that lacks a mesonotal suture. These physical characteristics allowed for the unequivocal identification of the specimens collected in the Tenerife area. Furthermore, the study expanded its scope to molecular identification to confirm the species and assess its evolutionary history.

To confirm the species identity at a molecular level, DNA barcoding was performed on two specimens. DNA was successfully extracted from the samples using the Mag-Bind Blood & Tissue DNA HDQ 96 kit and subsequently amplified targeting the 5’ region (658 bp) of the mitochondrial COI gene. The Polymerase Chain Reaction (PCR) reaction followed a specific protocol involving initial denaturation at 95 °C for 4 minutes, followed by 40 cycles of thermal cycling (94 °C for 45 s, 47 °C for 45 s, and 72 °C for 90 s), and a final extension. The resulting PCR products were sequenced using Sanger DNA sequencing and subsequently analyzed using the Barcode of Life Data Systems (BOLD Systems) identification engine. This robust molecular approach provided definitive proof of the presence of *W. auropunctata* in Tenerife.

The molecular analysis provided even deeper insights into the invasion history of the species. Two 619-bp sequences with no ambiguities were obtained, which were 99.5% identical to sequences identified as *W. auropunctata* from Ecuador, clustering with sequences from Peru. In contrast, the single available sequence from the western Palearctic, originating from Málaga, mainland Spain, showed a significant genetic divergence. This Málaga sequence was 100% identical to a sequence from Argentina and clustered with sequences from Argentina and Gabon. Crucially, the Canary Islands sequence displayed a similarity of only 91.3% to the mainland Spain (Málaga) sequence. This high genetic divergence, amounting to 8.7%, is substantial and exceeds what is typically found within a single species, suggesting that the Tenerife population represents a distinct lineage. This finding strongly supports the hypothesis that the western Palearctic has been colonized by *W. auropunctata* via at least two independent introduction events.

The invasive success of *W. auropunctata* is further amplified by its unique reproductive strategies in introduced environments. While natural populations typically exhibit a haplodiploid reproductive system, populations in disturbed and introduced areas, such as those found in the Canary Islands, consist of queens produced through thelytokous parthenogenesis and males generated by a male clonality system. This unusual reproductive strategy is a key factor enabling the successful establishment of small founder colonies, even when the initial genetic diversity is low. This clonal reproductive system allows the species to preserve heterozygosity and avoid the detrimental consequences of inbreeding, which is often a concern in small founding populations. These biological mechanisms, combined with its ability to form supercolonies—which can extend hundreds of kilometers with interconnected nests—allow *W. auropunctata* to reach estimated densities exceeding 20,000 workers per square meter, a density that surpasses that of *Solenopsis invicta*.

The management of *W. auropunctata* requires immediate and coordinated action, especially given its potential to spread rapidly through human-modified habitats, which are often the entry points for invasive species. Globalisation and the massive movement of goods mean that materials like agricultural, horticultural, and construction items are frequently transported across borders without effective customs inspections. This has facilitated the rapid range expansion of the species. While local eradication efforts have seen success elsewhere—such as in Marchena island in the Galápagos archipelago, where 21 hectares were successfully eradicated, and in the Hawaiian archipelago—the threat remains significant. In the Canary Islands, the current known distribution is restricted to the golf course and its surrounding gardens, with an estimated maximum area of no more than 55 hectares. However, given the high population density of Tenerife (2,263 inhabitants/km²) and its status as a major tourist hub with high traffic, the potential for further undetected spread is high, necessitating intensive biosurveillance and proactive control measures to prevent a wider ecological crisis.

Subject of Research: Detection and molecular characterization of *Wasmannia auropunctata* in the Canary Islands.

Article Title: Is the spread of Wasmannia auropunctata ( Hymenoptera , Formicidae ) through the western Palearctic inevitable? First evidence of presence in the Canary Islands

Article References: Pérez-Delgado, A. J., Santos-Perdomo, I., Jiménez-García, E., Lugo, D., & Suárez, D. (2025). Is the spread of Wasmannia auropunctata (Hymenoptera, Formicidae) through the western Palearctic inevitable? First evidence of presence in the Canary Islands. Journal of Hymenoptera Research, 98, 419-433. https://doi.org/10.3897/jhr.98.144997

Image Credits: AI Generated

DOI: 10.3897/jhr.98.144997

Keywords: Wasmannia auropunctata, Invasive Species, Canary Islands, Palearctic, Biodiversity, Molecular Identification, Ant Ecology, Biosecurity, spread, Wasmannia, auropunctata, Hymenoptera