A literature review was carried out to collate all available records of alien ants reported from Cyprus including species catalogued in the Global Ant Biodiversity Informatics (GABI) database (Janicki et al. 2016; Guénard et al. 2017) and scientific literature (Emery 1909, 1910; Georghiou 1977; Georgiadis et al. 2017; Salata et al. 2019; Demetriou et al. 2022, 2023a). In addition, specimens collected in the field by the authors on the island during 2012, 2021 and 2022, deposited in the collections of L. Borowiec and S. Salata (Department of Biodiversity and Evolutionary Taxonomy, University of Wrocław, Poland – DBET), Ch. Georgiadis (Museum of Zoology of the University of Athens, Greece – ZMUA), J. Wetterer (Smithsonian National Museum of Natural History, Washington, USA) and J. Demetriou (pers. collection) as well as material in the Museum of Natural History of the University of Wroclaw, Poland (MNHW) and Natural History Museum of Crete (NHMC) were examined (Suppl. material 1).

The identification of the ants was performed by comparing the specimens with type material deposited in museum collections such as that of MNHW alongside regional works on European ants and recent published revisions for genera and species complexes/groups (Agosti and Collingwood 1987; Seifert 2003, 2018, 2020; Czechowski et al. 2012; Seifert et al. 2017; Wagner et al. 2017).

The establishment status of alien ants was catalogued as Established i.e. “non-native species records with established populations in the wild” or Indoors introduced i.e. “non-native species records without established populations in the wild (e.g. in buildings, greenhouses, airports, quarantine surveys)” noting that within GABI the equivalent categories are given as exotic (= established) and indoors introduced (Janicki et al. 2016; Guénard et al. 2017). Lastly, the establishment status of data-deficient species is given as “Unknown”.

The native origin of species was decided based on GABI accessed through the antmaps.org website (Janicki et al. 2016; Guénard et al. 2017) and available scientific literature on the native range of species. Each species was assigned to one or more biogeographic realms sensu Holt et al. (2013). Criteria in Essl et al. (2018) were also applied to determine whether some species could be regarded as alien or native.

A dichotomous identification key to distinguish alien from native ant species inhabiting Cyprus was constructed using available scientific literature and specimens (Seifert 2003; Sharaf et al. 2016; Salata et al. 2020; Gotzek and Martinez 2021; Borowiec and Salata 2022). Additionally, several alien and invasive alien species included in the 100 of the world’s worst invasive alien species (Anoplolepis gracilipes, Linepithema humile, Pheidole megacephala, Solenopsis invicta and Wasmannia auropunctata) (GISD 2023), alien invasive species of Union Concern (Solenopsis geminata, S. invicta, S. richteri and W. auropunctata) (EU 2022/1203), species listed in a horizon scanning exercise (Peyton et al. 2019) (L. humile and W. auropunctata), alien ant species inhabiting the Eastern Mediterranean (Janicki et al. 2016; Guénard et al. 2017) as well as international and regional lists of widespread alien ants (Vonshak and Ionescu-Hirsch 2009; Wetterer 2009a, 2014a, b; Pospischil 2011; Borowiec 2014; Schifani 2019; Kiran and Karaman 2020; Salata et al. 2020; Pawluk et al. 2022a, b; Demetriou et al. 2023a) were added to the identification key to facilitate early detection, monitoring and management efforts across Cyprus.

The distribution of alien ant species within Cyprus was mapped. A total of 281 georeferenced observations (Suppl. material 1) were pooled in QGIS Version 3.18.2 free and open source Geographic Information System (https://qgis.org/en/site/) and were assigned to their respective land cover and presence within the NATURA2000 network. Boundaries and habitat types were based on the European layers of Corine Land Cover (CLC) project version CLC2018 and NATURA2000 sites, downloaded from Copernicus Land Monitoring Service and the European Environmental Agency, respectively. The occurrence of species within the boundaries of the protected RAMSAR site of Akrotiri (https://rsis.ramsar.org/RISapp/files/1375/pictures/GB1375map.pdf) (RAMSAR site code: 1375), was also documented. In addition to these distribution maps, information on occupied habitats are given, providing additional information alongside the broad CLC types. Therefore, with reference to the Copernicus Land Monitoring Service, records of ants within the following land-cover types were mapped: artificial surfaces, agricultural areas, forest and semi-natural areas, wetlands and water bodies as well as their respective sub-categories (https://land.copernicus.eu/user-corner/technical-library/corine-land-cover-nomenclature-guidelines/html). The area of occupancy (AOO) and extent of occurrence (EOO) of species were calculated through GeoCAT in a 2 × 2 km² grid, following guidelines of the International Union for the Conservation of Nature (IUCN) for the assessment of extinction risk of taxa (IUCN 2001; Bachman et al. 2011).

Photographs of specimens, unless stated otherwise, were taken by Prof. L. Borowiec using Nikon SMZ18 and Nikon SMZ 1500 stereomicroscopes, Nikon D5200 camera and Helicon Focus software. Locality data for each photographed specimen are provided in the figure titles.

Formicinae

Formicini

Camponotus cf. vitiosus

Fig. 2

Literature records. (Salata et al. 2023b).

Material examined. Suppl. material 1.

Origin. Sino-Japanese biogeographic realm.

Habitat details. Collected once from Cedar valley (Paphos), in high altitude (1196 m) in natural pine and cedar forest (Salata et al. 2023b).

Degree of establishment. Unknown.

Notes. A species resembling C. vitiosus was first recorded for the Mediterranean Basin from Israel, as Camponotus (Myrmamblys) sp. near vitiosus Smith, F., 1874 (Ionescu-Hirsch 2009). Specimens were intercepted at the Ashdod Port “in bamboo from China” (Ionescu-Hirsch 2009), while no additional records of the species have been provided since. A worker and a queen of the species were collected from the Cedar valley in 2012, situated within the Troodos mountain range, and the overlapping protected NATURA 2000 sites CY2000006 and CY2000016. Follow-up field surveys in 2022 provided no further material. In its native range (China, Japan and Korea), C. vitiosus has been collected both from urban and natural habitats in the lowlands and high mountains (Guénard and Dunn 2012; Kim and Lyu 2012; Park et al. 2014). The exact identity of this morphospecies will be further investigated with the help of molecular tools and sampling to retrieve any additional material.

Lasiini

Nylanderia jaegerskioeldi (Mayr, 1904)

Fig. 3

Literature records. Emery (1910); Georgiadis et al. (2017); Salata et al. (2019).

Material examined. Suppl. material 1.

Origin. Africa and Arabian Peninsula (Afrotropical and Saharo-Arabian biogeographic realms).

Habitat details. Common synanthropic species collected from urban habitats, plant nurseries, and households as well as from semi-natural and natural habitats such as a beach, stream valley, canyon, pastureland, and a river bank.

Degree of establishment. Established.

Notes. In Sicily aggressive behaviour towards Pheidole pallidula (Nylander, 1849) has been observed, although typically across the Mediterranean N. jaegerskioeldi is mostly collected from anthropogenic habitats (Obregón Romero and Reyes López 2012; Schifani and Alicata 2018; Reyes-López and Taheri 2018). In Cyprus, the species has been found indoors as a household pest, as well as in five natural protected areas including the Akrotiri marsh RAMSAR site. More research on its impacts on native ant communities is required.

Paratrechina longicornis (Latreille, 1802)

Fig. 4

Literature records. Salata et al. (2019).

Material examined. Suppl. material 1.

Origin. Indian subcontinent (Tseng et al. 2022) (Indomalayan biogeographic realm).

Habitat details. Common species in urban areas (garden, parks, parking lots, roadsides) and disturbed semi-natural habitats (beach, dirt road, field, waterfront).

Degree of establishment. Established.

Notes. This synanthropic species is widespread across Cyprus and has been collected from a variety of habitats. In Greece, P. longicornis can be found in the Dodecanese, inhabiting disturbed habitats in the lowlands and invading households (Borowiec and Salata 2022). Nevertheless, the species has been found to co-occur with native species, showing no signs of aggression (Salata et al. 2019). In Cyprus, the species can be found in urban and semi-natural habitats with evident human intervention and no adverse impact on native ant species has been observed. Nevertheless, detailed studies on the impacts of P. longicornis on native biodiversity are necessary. Paratrechina longicornis is also known to tend honeydew producing Hemiptera such as aphids (Saddiqui et al. 2019). In Cyprus, it was collected from Eucalyptus foliage probably feeding on honeydew secreted from Glycaspis brimblecombei Moore, 1964. Such a behaviour could exacerbate the socio-economic impacts of the psyllid. Further research on the impacts of the species as a household pest and its interactions with agricultural pests such as aphids or the alien cricket Myrmecophilus americanus Saussure, 1877 (Wetterer and Hugel 2014) could be prioritised.

Myrmicinae

Attini

Pheidole fadli Sharaf, 2007

Fig. 5

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Egypt (Sino-Arabian biogeographic realm).

Habitat details. Only one specimen collected from a plant nursery in Paphos. Probably unintentionally introduced through the horticultural pathway in soil.

Degree of establishment. Unknown.

Notes. The species was first described in Fadl et al. (2007) from specimens collected near the river Nile and was considered to be endemic to Egypt. A single specimen was collected in Paphos from a plant nursery, under plastic sheets placed on the soil. It was probably introduced unintentionally in potted plants from Egypt but this is not confirmed. The high soil moisture and temperature in the glasshouse may have provided suitable microhabitats for the species.

Pheidole indica Mayr, 1879

Fig. 6

Literature records. Salata et al. (2019).

Material examined. Suppl. material 1.

Origin. Indomalayan biogeographic realm.

Habitat details. Inhabiting urban habitats including parks, parking lots, pedestrian paths, plant nurseries, ports and parks as well as semi-natural habitats associated with humans such as sea and lake shores.

Degree of establishment. Established.

Notes. Synanthropic species collected from urban and semi-natural habitats in which there is human activity. In the Balearics, it [as Ph. teneriffana] has been observed to attack native Tetramorium cf. caespitum (Gómez and Espadaler 2006). Nevertheless, according to Sarnat et al. (2015), “Pheidole indica is not considered to be a major pest to either agriculture or native ecosystems”, although “further studies are required to test its ecological and agricultural impact outside its native range”.

Wasmannia auropunctata (Roger, 1863)

Fig. 7

Literature records. Demetriou et al. (2022).

Material examined. Suppl. material 1.

Origin. Central and South America (Panamian and Neotropical biogeographic realms).

Habitat details. Exclusively associated with human presence. Specimens have been collected from plant nurseries, greenhouses, urban parks, parking lots and pedestrian paths near hotels and tourist sites.

Degree of establishment. Established.

Notes. In invaded territories, W. auropunctata has been found to negatively affect native biodiversity as well as human and animal health (Lubin 1984; Hayashi 1999; Wetterer et al. 1999; Roque-Albelo and Causton 1999; Nishida and Evenhuis 2000; Roque-Albelo et al. 2000; Wetterer and Porter 2003; Mbenoun-Masse et al. 2017; Kidon et al. 2022). Only recently detected in Cyprus (Demetriou et al. 2022), W. auropunctata seems to be widely distributed in the Western part of the island (Paphos district). The abundance of the species seems to be variable, with only a few specimens collected from some sites and very high numbers from others. For example, in tourist sites, such as a hotel garden in Coral Bay and the Kato Paphos harbour, large numbers of the species were recovered while beating ornamental plants (Hibiscus rosa-sinensis and Ficus microcarpa), while sidewalks of a park in Mesogi, a hotel garden in Coral Bay and a hotel parking lot had very large colonies. More research is needed to comprehensively map the distribution of W. auropunctata in Cyprus and to assess interactions with native ants.

Crematogastrini

Cardiocondyla mauritanica Forel, 1890

Fig. 8

Literature records. Emery (1909).

Material examined. Suppl. material 1.

Origin. Saharo-Arabian biogeographic realm.

Habitat details. Found in urban (park, parking lot), agricultural (plant nursery) and natural habitats (dry river bank, reservoir).

Degree of establishment. Established.

Notes. Cardiocondyla mauritanica is known to prefer xerothermous, urban and semi-arid environments (Seifert 2003; Wetterer 2014b). According to its ecological preferences, in Cyprus it has been collected from the lowlands, in disturbed areas with evident human interference.

Cardiocondyla obscurior Wheeler, W.M., 1929

Fig. 9

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Indomalayan biogeographic realm.

Habitat details. Collected from urban habitats in Paphos foraging on trees, shrubs as well as on the ground in gardens and parking lots.

Degree of establishment. Established.

Notes. Native to Indomalaya, C. obscurior has been recorded from Europe and the Mediterranean as an indoor introduced species in France, Germany and the Netherlands (Seifert 2003; Blatrix et al. 2018; Boer et al. 2018) as well as an established alien species in Egypt, Israel, Syria and Spain (Donisthorpe 1930; Mohamed et al. 2001; Seifert 2003; Sánchez-García and Espadaler 2015; Janicki et al. 2016; Trigos Peral and Reyes-López 2016; Espadaler and Ortiz de Zugasti 2019). In contrast to recent findings of a single specimen in Greece (Demetriou et al. 2023b), C. obscurior seems to be established on the island of Cyprus with specimens being collected both on trees, according to its arboreal habits (Espadaler and Ortiz de Zugasti 2019) and from the soil.

Tetramorium bicarinatum (Nylander, 1846)

Fig. 10

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Indomalayan biogeographic realm.

Habitat details. Collected from two plant nurseries and a zoo in Paphos.

Degree of establishment. Indoor introduced.

Notes. The distribution of this species on the island of Cyprus should be monitored. It is predicted to have socio-economic impacts on households or horticultural plants, through mutualistic relationships with aphids and scale-insects including Aphis gossypii Glover, 1877 (Saddiqui et al. 2019), an alien aphid species collected from a variety of arable and ornamental plants (Morris 1937; Georghiou 1977).

Tetramorium caldarium (Roger, 1857)

Fig. 11

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Afrotropical biogeographic realm.

Habitat details. Found only from a zoo.

Degree of establishment. Unknown.

Notes. A species that has been detected only from a few countries in the Mediterranean region, including France (Radchenko 2004), mainland Spain and the Balearic Islands (Reyes and Espadaler 2005; Gómez and Espadaler 2006) as well as Egypt (Donisthorpe 1942) and Morocco (Cagniant and Espadaler 1993; Cagniant 1997; Taheri and Reyes-López 2018) in Northern Africa. According to Bolton (1980), the species is “associated with man and living in hothouses, zoos, or other constantly heated buildings”, although it has also been collected from urban habitats in gardens, terraces, and flowerpots (Cagniant 1997) being currently widespread in the cities and coasts of Morocco (Taheri and Reyes-López 2018). In Cyprus, the species has been collected only from a zoo, during ant collection on pavements and outdoors areas. Despite its worldwide distribution, no adverse ecological impacts have been recorded for the species (Wetterer and Hirta-Garcia 2015).

Tetramorium immigrans Santschi, 1927

Fig. 12

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Central Asia and Europe (Palearctic biogeographic realm).

Habitat details. Found from only two collecting sites in Paphos district, a zoo and Kato Paphos area.

Degree of establishment. Established.

Notes. A member of the recently taxonomically revised Tetramorium caespitum complex, currently widespread in Europe and the Mediterranean that has been found in anthropogenic and natural habitats (Wagner et al. 2017; Demetriou et al. 2023b). The species has been found to hybridise and compete with native Mediterranean species (Wagner et al. 2017; Cordonnier et al. 2019; Schifani et al. 2022). Although the native and invaded range of T. immigrans needs further examination, its presence in only two urban areas and absence from sampled natural habitats leads us to assume that the species is alien to the island.

Tetramorium lanuginosum Mayr, 1870

Fig. 13

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Subtropical East Asia (Indomalayan biogeographic realm).

Habitat details. Found in urban habitats including parking lots, urban green spaces with ornamental vegetation and a zoo.

Degree of establishment. Established.

Notes. The species has been collected from neighbouring Israel and Lebanon since the last century and more recently from Egypt (Wetterer 2010a). In Spain, T. lanuginosum was first recorded by Reyes and Espadaler (2005) and subsequently collected from a date palm grove where it presumably did not establish (Casiraghi et al. 2020). Tetramorium lanuginosum has been also recorded from urban habitats in Malta and Sicily (Schembri and Collingwood 1981; Schifani and Alicata 2018). In Cyprus it can be found in anthropogenic habitats, with two sites within the boundaries of the protected Akamas Peninsula (CY4000023 and CY4000010). Although the species has no recorded adverse environmental impacts, more research is necessary to establish its further spread into protected areas.

Solenopsidini

Monomorium bicolor Emery, 1877

Fig. 14

Literature records. Salata and Borowiec (2015b); Salata et al. (2019).

Material examined. Suppl. material 1.

Origin. Africa, Arabian Peninsula, Levant and Turkey (Palearctic, Saharo-Arabian and Afrotropical biogeographic realms).

Habitat details. Widespread, found in all kinds of habitats.

Degree of establishment. Established.

Notes. The most common and widespread alien ant in Cyprus, reaching the highest altitudinal range and collected from 15 protected areas. Despite its large AOO and EOO, it has been only recently detected in Cyprus (Salata and Borowiec 2015b) and does not seem to have any adverse environmental impacts. Nevertheless, the alien or native status of this species in the Middle East and in Cyprus is rather problematic. Monomorium bicolor is believed to be native to the Afrotropics (Bolton 1987) although on AntMaps it is shown as native to the whole of Africa and Middle East except Greece and Cyprus. Despite its recent report from Cyprus, its distribution on the island may suggest either its unintentional introduction since ancient times (L. Borowiec pers. comm.) or indeed its native status. Molecular analyses on populations from Cyprus, the Middle East, Northern and Sub-Saharan Africa could help to unveil the true status of the species in the aforementioned regions.

Solenopsis sp_CYP139

Fig. 15

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Unknown.

Habitat details. Collected from plant nurseries (indoors in crops under foil) and outdoor urban areas of Limassol and Paphos.

Degree of establishment. Established.

Notes. This unidentified species is well distinguished from all native species from Greece and Turkey; it is very small in size and has extremely small eyes (in the form of a black dot). We have decided to classify this morpho-species as alien due to its occurrence only within urban habitats and plant nurseries, which lead us to the hypothesis of an unintentional introduction via infested plant material. The species presumably belongs to an unidentified species of tropical/subtropical origin, which could be further investigated with the help of molecular tools. The description and morphometric data of this morphospecies can be found Suppl. material 4 for further examination and future comparisons.

Trichomyrmex destructor (Jerdon, 1851)

Fig. 16

Literature records. Georghiou (1977); Wetterer (2009b).

Material examined. Suppl. material 1.

Origin. Indomalayan biogeographic realm.

Habitat details. Urban habitats including houses, parking lots and paved roads.

Degree of establishment. Established.

Notes. Wetterer (2009b) cite “CAB 2000 in DAFF 2001” as a literature source for the presence of T. destructor in Cyprus. When checking CABI (2022) T. destructor was reported as present in Cyprus citing “CABI Data Mining (Undated)”. Despite comments of Salata et al. (2019) excluding the species from their list, Demetriou et al. (2023a) decided to include it based on records of Georghiou (1977), which had previously been overlooked. In particular, Georghiou (1977) noted this species as “Monomorium destructor Jerd.”, “from olives infested by Dacus oleae” in 1956 as well as in 1925 under the synonymic name “M. gracillimum Sm.” “feeding of eggs of Thaumatopoea wilkinsoni (Lep., Notodontidae)”. Upon collection of further material we confirm the presence of T. destructor on the island. The species was collected from five urban sites in Paphos and Limassol districts. Trichomyrmex destructor is known to be associated with electronic devices causing electrical damages as well as destroying stored household products and inflicting painful bites on humans (Wetterer 2009b). Negative socio-economic impacts in households or possible health risk could be monitored through citizen science initiatives assessing the socio-economic impacts of ants in households.

Trichomyrmex mayri (Forel, 1902)

Fig. 17

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Indomalayan biogeographic realm [speculated by Bolton (1987)].

Habitat details. Both in urban (dirt roads, road sides and uncultivated green spaces) and natural habitats (dry meadow, pine forest, reservoir).

Degree of establishment. Established.

Notes. A species common in the Arabian Peninsula (Sharaf et al. 2013), which is believed to originate from Indomalaya (Bolton 1987). It has been recorded from neighbouring Egypt, Israel and Syria where it is considered alien (Bolton 1987). In Cyprus, it occupies a large EOO and altitudinal range, while it has been also recorded from three protected areas (CY2000004, CY2000013 and RAMSAR1375). Nevertheless, its potential environmental or socio-economic impacts are unknown both throughout its native and introduced range.

Ponerinae

Ponerini

Hypoponera punctatissima (Roger, 1859)

Fig. 18

Literature records. N/A.

Material examined. Suppl. material 1.

Origin. Probably Egypt and Sub-Saharan Africa (Saharo-Arabian and Afrotropical biogeographic realms).

Habitat details. Only one collection site corresponding to a plant nursery (indoors in crops under foil) in Paphos.

Degree of establishment. Unknown.

Notes. An alien species collected across Europe and the Mediterranean from both indoors and outdoors localities, including natural habitats (Atanassov and Dlusskij 1992; Czechowski et al. 2012; Borowiec and Salata 2022). Although its native range remains quite uncertain, its presence on the island is supported by only one specimen collected in a plant nursery. This may indicate its recent introduction to the island through the horticultural or ornamental pathway, with further spread leading to its establishment in areas with sufficient humidity as observed in other European countries. Although Hypoponera ergatandria Forel, 1893 has been also noted as an alien species in Europe, the status of this species is uncertain, representing either a valid species or a junior synonym of H. punctatissima. As such, H. ergatandria is not included in the provided identification key and considered here as a junior synonym of H. punctatissima (Bolton and Fisher 2011; Seifert 2013; Lubertazzi 2019).

Cardiocondyla nuda (Mayr, 1866)

Notes. Although previously thought to be a widespread alien species, a revision of the group has concluded that C. nuda is geographically restricted in Oceania (Seifert et al. 2017). According to Seifert (2003), investigation of authentic material from the Palaearctic turned out to be C. mauritanica. Although the species is mentioned for Cyprus by Bernard (1956), these records also probably correspond to C. mauritanica.

Monomorium pharaonis (Linnaeus, 1758)

Notes. The only records of the species can be traced back to Wetterer (2010b) citing Radchenko (2004), a record corresponding to data in the Fauna Europaea database. Nevertheless, no specimens or scientific literature have been provided to support these records. The record of M. pharaonis in Fauna Europaea is probably erroneous as already shown for other ant species in the database, noted for example by Schifani and Alicata (2018) regarding Sicily or Demetriou et al. (2023b) for Greece. Although the presence of M. pharaonis on the island is highly possible, given its extended distribution throughout the world (Wetterer 2010b), we tentatively suggest the exclusion of the species from lists of alien species of Cyprus until further investigations provide adequate evidence. Citizen science approaches looking into the biodiversity and socio-economic impacts of ants in households could potentially uncover records of this synanthropic, indoors introduced species.

Monomorium subopacum (F. Smith, 1858)

Notes. As in the case of Greece (Demetriou et al. 2023b), following assumptions of Bolton (1987) and the native status of the species for neighbouring Mediterranean countries (AntWiki 2022), M. subopacum is considered native to Cyprus.

Nylanderia vividula (Nylander, 1846)

Notes. In Georghiou (1977) “Paratrechina nitidula Nyl.” is mentioned as collected in 1935 and identified by H.S. Donisthorpe. Such a nomenclatural combination does not exist and probably corresponds to Paratrechina vividula (Nylander, 1846), currently an obsolete combination of N. vividula. Nylanderia vividula has been reported as an alien species from neighbouring Egypt, Greece, Israel, Lebanon, and Turkey (Emery 1881, 1898; Donisthorpe 1950; Borowiec 2014). However, records from Greece are believed to correspond to N. jaegerskioeldi (Demetriou et al. 2023b) and no additional records have been uncovered from Turkey since Donisthorpe (1950). During our sampling in Cyprus we extensively collected only samples of N. jaegerskioeldi. Nylanderia vividula, a species native to the Nearctic biogeographic realm, might have been introduced to the island but failed to establish. Alternatively, records may correspond to N. jaegerskioeldi, a common species missing from Georghiou’s (1977) list but already known from Cyprus since 1910 (Emery 1910). Further sampling and tracing material in historical collections may shed light on the presence and invasion history of N. vividula on Cyprus. For the time being, records from Cyprus remain doubtful and in need of verification.

Solenopsis geminata (Fabricius, 1804)

Notes. The only record mentioning the presence of S. geminata in Cyprus can be traced to Collingwood et al. (1997), where the island is simply listed in the known distribution of the species. After 25 years of this mention no material has been uncovered. As in the case of Greece (Demetriou et al. 2023b), we expect that the presence and impacts of this invasive alien species would not go unnoticed. In the possible event of its past introduction to the island, any individuals or populations did not manage to establish. Furthermore, as horizon scanning exercises undertaken on the island (Peyton et al. 2019) did not assess S. geminata, due to the aforementioned dubious records, the possibility of the species reaching Cyprus, establishing viable populations and impacting native biodiversity, could be taken into consideration in the future.

Hypoponera eduardi (Forel, 1894)

Notes. Although included in the list of invasive ants of Greece and Cyprus (Salata et al. 2019), upon re-examination the species is currently treated by the authors as native to Cyprus due to both its narrow ecological requirements (i.e. soil moisture, habitat types found) as well as its native status in neighbouring countries (Demetriou et al. 2023b).

[After Borowiec and Salata (2022), modified]

[After Salata and Borowiec (2022), and Fisher and Bolton (2016), modified]

[After Borowiec and Salata (2022), modified]

[After Salata et a. (2020), Borowiec and Salata (2022), Bolton (1980, 2000) and Seifert (2023), modified]

[After Borowiec and Salata (2022) and Schmidt and Shattuck (2014), modified]

The number of known alien insect species in Cyprus has increased dramatically during the last decade (Demetriou et al. 2023a); there has been a steep increase in the number of recorded ants in part due to increased sampling intensity (Tables 1, 2). According to our analysis of CLC occupied by alien ants in Cyprus, the majority of species (90%) have been collected from anthropogenic habitats including artificial surfaces and agricultural land, with limited spread to forest and semi-natural areas or inland waters (Fig. 1). These data are in accordance with other similar observations, reporting alien insects, including ants, mostly dominating anthropogenic habitats (Espadaler and Bernal 2003; Lopez-Vaamonde et al. 2010; Schifani 2019; Rosas-Mejía et al. 2021; Demetriou et al. 2023b). Regarding the second level of CLC types, within artificial surfaces more than half of the habitats (54%) correspond to “urban fabric”, followed by “artificial, non-agricultural vegetated areas” (43%). Within agricultural land, “heterogeneous agricultural areas” dominate occupied habitats with a percentage of 69% of obtained records. Lastly, regarding forest and semi-natural areas, half of the occurrence records were classified as “shrub and/or herbaceous vegetation associations” (52%), followed by “forests” (33%) and “open spaces with little or no vegetation” (15%) (Suppl. material 1). Nevertheless, looking in greater detail into these forest and semi-natural areas and comparing these classifications with the notes taken on the habitat during the surveys, some correspond to traffic islands, roadsides, urban habitats and/or other areas with evident human pressure and modifications. This comes to show that the spread of alien ants into natural habitat types is perhaps limited and that their spread is probably favoured by anthropogenic habitat heterogeneity (Elton 1958; Hobbs and Huenneke 1992; Melbourne et al. 2007).

The NATURA 2000 and RAMSAR wetland networks also seem not to be impervious to biological invasions of ants, with seven species being present in a total of 20 protected areas (Suppl. material 2). Many records were situated around the edges of protected areas, as already reported by Liu et al. (2020), with the most noticeable case in Cyprus being that of W. auropunctata, collected just outside the protected areas of Faros Kato Paphou (CY4000013), Chersonisos Akama (CY4000010) and Ekboles Potamon Ezousas, Xerou, kai Diarizou (CY4000018) in Paphos. The alien ant fauna of the island both within protected areas and surrounding areas (Holenstein et al. 2021), should be further monitored to increase understanding of potential adverse effects on native biodiversity and protected habitat types. The Akamas Peninsula (CY4000010 and CY4000023) is of particular importance because of increasing pressure from urban developments which may increase the number and spread of alien species. Four alien species, M. bicolor, N. jaegerskioeldi, P. longicornis and T. lanuginosum have already been identified from the region, although no adverse effects have been reported. Although protected areas have been reported as refuges for native species against invasive alien species (Gallardo et al. 2017), the spread and establishment of species such as W. auropunctata should be monitored further.

Twelve out of 17 species are considered to be established with self-sustaining populations on the island; one is considered as an introduction to indoors because it is confined to plant nurseries and the zoo (i.e. T. bicarinatum). For four species, C. cf. vitiosus, H. punctatissima, P. fadli and T. caldarium, the establishment status is currently unknown because only single records/specimens have been found. These species may represent recent introductions that will fail to establish but ongoing monitoring is recommended. It is important to mention that the greenhouse in which P. fadli was detected, was destroyed and reconstructed (paved) a few months after the specimen’s collection (Demetriou pers. obs.).

Although introduction pathways of alien ants in Cyprus are largely unknown, plant nurseries seem to play a crucial role in the movement of alien ants (Jucker et al. 2008; Pospischil 2011; Blatrix et al. 2018). As shown in our study, six alien ant species were collected from plant nurseries and greenhouses with P. fadli and H. punctatissima known only from such localities. This shows that alien ants can be moved outside their native range in the soil of potted plants, as hypothesised for W. auropunctata (Vonshak et al. 2010; Demetriou et al. 2022), potentially bypassing phytosanitary inspections and border controls (Rabitsch 2011; Wong et al. 2023). The identification key aims to support detection and monitoring activities. Quarantine measures or chemical treatment could be implemented for imported plant material to mitigate further spread of invasive alien species such as S. geminata, S. invicta, S. richteri, and W. auropunctata (Rabitsch 2022a, b).

There is a lack of information on the environmental and socio-economic impacts of alien ants inhabiting Cyprus, although some invasive alien species have been scored as high through global impact assessments such as W. auropunctata, P. longicornis, T. bicarinatum, and T. destructor (Salata et al. 2019; Demetriou et al. 2022; Gruber et al. 2022; present study). Furthermore, according to Salata et al. (2019) aggressive behaviour towards native ant species has been observed by N. jaegerskioeldi but such observations are not supported by quantified analyses suggesting the need for further studies. These species should be considered for prioritisation on lists with further ongoing research on their impacts. As an example W. auropunctata has been listed both as one of the world’s worst invasive alien species (GISD 2023) and as an invasive alien species of Union Concern (EU 1143/2014; EU 2022/1203). Currently, no other native species have been found to occur in sites heavily infested by W. auropunctata and for the moment no spread in natural habitats has been observed (Demetriou pers. obs.).

Wasmannia auropunctata has the potential to threaten human and animal health because it can sting and in rare cases cause anaphylactic shocks with the potential to harm both wild and domesticated animals (Wetterer and Porter 2003; Kidon et al. 2022). Infestations of electronic devices by T. destructor also pose a potentially life-threatening socio-economic impact of ants on the island. Citizen science is being considered as an approach by the authors to assess the socio-economic impacts of ants in Cyprus and particularly their impacts in households. Such an initiative could also be used to enhance understanding of the presence of other alien species, verify past records of M. pharaonis, raise awareness of the impacts of alien ants as well as provide adequate data to perform risk assessments under EICAT and SEICAT protocols (Hawkins et al. 2015; Bacher et al. 2018).