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Taxonomic name: Lasius neglectus Van Loon, Boomsma & Andrásfalvy, 1990 Synonyms: Common names: invasive garden ant (English) Organism type: insect Lasius neglectus is a recent arrival in Europe. Some of its populations have attained pest status but on other sites, the ant is still in an arrested state, perhaps in the lag-phase, lacking the major characteristics of invaders. Its negative effects are caused by the enormous numbers of ants tending aphids on trees and occupation of electrical conduits in homes and gardens. Description Lasius neglectus, though known to be present at a location in Budapest, Hungary, was only described in 1990 (Van Loon et al. 1990). It is a member of the sub-family Formicinae. The length of the worker, queen and male are 2.5-3mm (worker), 5.5-6mm (queen), 2.5mm (male); the mandibles are 7-toothed; hairs are lacking on the scape (first segment of antenna) and usually on the legs. Their colour is yellowish-brown with the thorax somewhat paler. The live weight of the worker is 0.65-0.80mg and the queen, 6.8-9.6mg. Espadaler and Bernal (2004) observed that "the female is immediatly recognisable within the European Lasius by its comparatively reduced size and proportionately smaller gaster (swollen part of abdomen), as compared with the thorax. The male is the smallest within the European Lasius (s.str.) species". Polygyny in the nest (the presence of more than one functional queen), and the enormous numbers of workers travelling up and down trees is also a characteristic of the species. Similar Species Lasius austriacus, Lasius turcicus More Occurs in: ruderal/disturbed, urban areas Habitat description In Europe Lasius neglectus is found in urbanised areas, from city streets to semi-urban lots with some natural vegetation. Trees are a key resource for the ant. In Asia Minor it is found in natural steppe habitats (Seifert, 2000). General impacts Lasius neglectus may invade the interior of houses and occupy electrical conduits, causing short-circuits or damage to electro-mechanical devices. Outdoors, it nests at the base of plants and attends aphids on trees, usually producing negative effects. As a result of the ants protecting aphids and "milking" them for their honeydew it causes honeydew to be produced in large quantities, in turn causing sooty mould to grow on leaves. Not all populations seem to be invasive, in Spain only three out of eleven populations have been denounced as damaging or invasive. This is probably due to climatic constraints, especially dryness during the Mediterranean summer. Notes Lasius neglectus is a poorly known species living in huge supercolonies with no apparent within-colony boundaries, and with a highly polygynous kin-structure (Van Loon et al. 1990; Boomsma et al. 1990) Geographical range Native range: Lasius neglectus is probably native to Turkey. Known introduced range: L. neglectus has expanded westwards to many European countries and has reached the Canary Islands (Espadaler and Bernal, 2003). It has been reported in Belgium, Bulgaria, France, Georgia, Germany, Greece, Hungary, Iran, Italy, Kyrgystan, Romania, Spain and Uzbekistan. For comprehensive updated information on distribution, with maps, coordinates, locality, country and references please see Distribution Lasius neglectus Introduction pathways to new locations Transportation of habitat material: Movement of potted plants, turf peat, soil from construction. Local dispersal methods Natural dispersal (local): Movement of soil or cuttings of vegetation. Management information Preventative measures: The Pacific Ant Prevention Programme is a proposal prepared for the Pacific Plant Protection Organisation and Regional Technical Meeting for Plant Protection. This plan aims to prevent the red imported fire ant and other invasive ant species with economic, environmental or social impacts from establishing within or spreading between countries in the Pacific. A detailed pest risk assessment for the eight species ranked as having the highest potential risk to New Zealand (Anoplolepis gracilipes, Lasius neglectus, Monomorium destructor, Paratrechina longicornis, Solenopsis geminata, Solenopsis richteri, Tapinoma melanocephalum, Wasmannia auropunctata) was prepared as part of 'The invasive ant risk assessment project', Harris et al. 2005., for Biosecurity New Zealand by Landcare Research. Lasius neglectus scored as a high-risk threat to New Zealand. The Invasive ant risk assessment for Lasius neglectus can be viewed at Lasius neglectus risk assessment. Please see Lasius neglectus information sheet for more information on biology, distribution, pest status and control technologies. Integrated Pest Management: Usual measures against domestic ants are not expected to be effective. The enormous numbers of ants that integrate in the supercolonies are to be controlled by an Integrated Pest Management (IPM) strategy, involving both chemical control on trees and soil, physical management of trees (cutting branches in contact with buildings) and limiting irrigation as much as possible (Rey and Espadaler, 2005). Please follow this link for more detailed information on the management of the Lasius neglectus compiled by the ISSG. Nutrition Feeding is mainly based on sugary foods (aphid honeydew, nectar, vegetal juices). In spring the ants look for aphids at the base of herbs and small vegetation, where the ant constructs temporary earth shelters. In summer, when tree aphids are abundant, the ants shift to this nearly ubiquitous resource. Reproduction The colony grows by budding, involving the displacement of queens with some workers at short distances (a few metres). In laboratory studies, isolated queens have also been shown to be able to found new colonies, although it is not known if this possibility exists under natural conditions. The carbohydrate content of newly mated queens is consistent with the observed loss of mating flight of this species although the relative wing area indicates that L. neglectus queens should be able to fly. Lifecycle stages Lifecycle stages (data from one colony in north-east Spain): eggs (from April to October), larvae (all year around), worker pupae (May, June, September, October), sexuals pupae (May, June), winged sexuals (May, June). Reviewed by: Xavier Espadaler CREAF-Unitat d'Ecologia Universitat Autònoma de Barcelona Spain Principal sources: Van Loon et al. 1990; Boomsma et al. 1990; Seifert, 2000; Espadaler & Rey, 2001; Espadaler and Bernal, 2004 Compiled by: Wayne J. Crans, Director - Mosquito Research, Rutgers University, New Brunswick, NJ. USA & IUCN/SSC Invasive Species Specialist Group (ISSG) To contribute information, please contact Shyama Pagad. Last Modified: Wednesday, 28 October 2009