Lasius neglectus is a small to mid-sized (2.5–3.5 mm) dull brown species with lighter brown appendages, dense pubescence, and a truncated propodeum. The species, which is believed to be native to Asia Minor, has been spreading across Europe for at least the past 40 years, but prior to its formal description (van Loon et al., 1990), L. neglectus had been treated as its two close relatives, L. alienus and L. turcicus Santschi (Seifert, 2000). The species, described from Budapest, is now known from other locations within Hungary and from Belgium, Bulgaria, France, Georgia, Germany, Greece, Italy, Kyrgyzstan, Poland, Rumania, Spain, Turkey, and the Canary Islands (Espadaler & Bernal, 2003;2004; Seifert, 2000). Lasius neglectus is likely present in other European cities, but is yet to reach densities high enough to cause reporting and identification (Harris et al., 2005). In addition to dominating resources to the likely detriment of native species, L. neglectus is also known to cause damage to vegetation and occupy buildings. The temperate habitat and invasive characteristics demonstrated by L. neglectus suggest it could become widespread in North America if a population becomes established. For a comprehensive fact sheet detailing the history, biology, pest significance of L. neglectus, along with an exemplary risk analysis for establishment in New Zealand, the reader is referred to Harris et al. (2005).
Native range. Asia Minor.
Introduced range. Includes: Budapest, is now known from other locations within Hungary and from Belgium, Bulgaria, France, Georgia, Germany, Greece, Italy, Kyrgyzstan, Poland, Rumania, Spain, Turkey, and the Canary Islands.
Lasius neglectus is unicolonial and polygynous, allowing it to form supercolonies of approximately 35,000 queens and 100 million workers across 14 ha (Espadaler & Bernal, 2004; Seifert, 2010). Populations studied in Spain showed strong activity when temperatures reached 20°C from early March to late November (Espadaler & Bernal, 2004). Aphid honeydew from a wide variety of aphid species (van Loon et al., 1990)is a primary food resource for L. neglectus, and the species is effective at dominating productive areas by displacing competing ant species (Espadaler & Bernal, 2004). Nesting sites include soil beneath stones, temporal refuges with aphids at the base of herbs, in grassy slopes, among tree roots, in apparently barren soil, and rubbish (Espadaler & Bernal, 2004; Harris et al., 2005). In its introduced range, L. neglectus is most closely associated with urban areas and disturbed habitats. The two most common means of dispersal for the species are human-assisted transport and colony budding. Lasius neglectus is not known to make nuptial flights, and it is assumed to practice intranidal mating (Seifert, 2000). Queen morphology and physiological state at maturity suggest that L. neglectus is intermediate between a monogyne independent colony forming species and other polygyne invasive tramp ant species (Espadaler & Rey, 2001).
Lasius neglectus is likely to prove a significant pest with regards to the native environment, agriculture and human habitations. Little is known about the effects L. neglectus has on other ants, but there is some evidence that it displaces other species that might compete for food or nesting resources (Dekoninck et al., 2002; Espadaler & Bernal, 2004; Espadaler & Rey, 2001; Tartally, 2000). The effects of aphid tending is very detrimental to trees and crops (Espadaler & Bernal, 2004; Espadaler & Rey, 2001; van Loon et al., 1990). The ants are also attracted to electrical fields and cause damage to electrical devices (Espadaler & Bernal, 2004).
Diagnosis among workers of introduced and commonly intercepted ants in the United States. Worker caste monomorphic. Antenna 12-segmented. Antennal club indistinct. Antennal scape length less than 1.5x head length. Eyes medium-sized (greater than 5 facets). Three distinct ocelli present. Mandibles with 7 (rarely 8) teeth including 2 basal teeth. Promesonotum separated from propodeum by metanotal groove, but not by a deep and broad concavity. Propodeum and petiolar node both lack a pair of short teeth. Propodeum lacking posteriorly projecting protrusion. Propodeal declivity at least twice length of propodeal dorsum. Metapleuron with a distinct gland orifice. Waist 1-segmented. Petiole upright and not appearing flattened. Gaster armed with acidopore. Distinct constriction not visible between abdominal segments 3+4. Erect hairs present on mesosoma, but not long thick and produced in pairs. Head length = 0.72–0.88 mm. Head width = 0.64–0.81 mm. Scape length = 0.68–0.80 mm.
Lasius neglectus can be separated from introduced species in the United States and commonly intercepted formicine genera by the combination of the following characters: (1) antenna 12-segmented; (2) monomorphic worker caste; (3) three distinct ocelli; (4) metapleural gland present; and (5) propodeal declivity at least twice length of propodeal dorsum. Separating L. neglectus from the native L. alienus is difficult. The mandibles of L. neglectus have seven or rarely eight teeth, two of which are basal (versus eight (or rarely nine) teeth, three of which are basal in L. alienus). Lasius neglectus is also relatively smaller (HW = 0.64–0.81 mm, versus 0.68–0.92 mm in L. alienus), with generally longer antennal scapes (SL = 0.68–80 mm, versus 0.72–0.89 mm in L. alienus). Lastly, L. neglectus is polygynous while L. alienus is polygynous. Additional morphometric characters used to separate the two species are available in Seifert (1992)and summarized in Espadaler & Bernal (2004), but beware that these characters are averaged across workers of entire colonies.
Dekoninck, W., De Baere, C., Mertens, J. & Maelfait, J.P. (2002) On the arrival of the Asian invader ant Lasius neglectus in Belgium (Hymenoptera, Formicidae). Bull. Ann. Soc. R. Entomol. Belg., 138, 45-48.
Espadaler, X. & Bernal, V. (2003) Exotic ants in the Canary Islands, Spain (Hymenoptera, Formicidae). Vieraea, 31, 1-7.
Espadaler, X. & Bernal, V. (2004) Lasius neglectus. CREF, UAB
Espadaler, X. & Rey, S. (2001) Biological constraints and colony founding in the polygynous invasive ant Lasius neglectus (Hymenoptera, Formicidae). Insect. Soc., 48, 159-164.
Harris, R., Abbott, K., Barton, K., Berry, J., Don, W., Gunawardana, D., Lester, P., Rees, J., Stanley, M., Sutherland, A. & Toft, R. (2005) Invasive ant pest risk assessment project for Biosecurity New Zealand. Series of unpublished Landcare Research contract reports to Biosecurity New Zealand. BAH/35/2004-1
Schultz, R. & Seifert, B. (2005) Lasius neglectus (Hymenoptera: Formicidae) - a widely distributed tramp species in Central Asia. Myrmecol. Nachr., 7, 47-50.
Seifert, B. (1992) A taxonomic revision of the Palaearctic members of the ant subgenus Lasius s. str. (Hymenoptera: Formicidae). Abh. Ber. Naturkundemus. Gorlitz, 66(5), 1-66.
Seifert, B. (2000) Rapid range expansion in Lasius neglectus (Hymenoptera, Formicidae)- an Asian invader swamps Europe. Dtsch. Entomol. Z., 47, 173-179.
Seifert, B. (2010) Intranidal mating, gyne polymorphism, polygyny, and supercoloniality as factors for sympatric and parapatric speciation in ants. Ecol. Entomol., 35, 33-40.
Tartally, A. (2000) Notes on the coexistence of the supercolonial Lasius neglectus Van Loon, Boomsma et Andrásfalvy 1990 (Hymenoptera: Formicidae) with other ant species. Tiscia (Szeged), 32, 43-46.
van Loon, A.J., Boomsma, J.J. & Andrásfalvy, A. (1990) A new polygynous Lasius species (Hymenoptera: Formicidae) from central Europe. I. Description and general biology. Insect. Soc., 37, 348-362.
Found most commonly in these habitats: 1 times found in Forest
Collected most commonly using these methods or in the following microhabitats: 1 times Winkler
Elevations: collected from 20 - 270 meters, 147 meters average