Lasius emarginatus
(Olivier, 1792)
ManhattAnt, Central European Bicolored Ant
Lasius emarginatus is a small formicine to western Eurasia that has become a notable in North America. First discovered in New York City in 2011, it earned the nickname "ManhattAnt" and has since become one of the most common ants in the city, spreading at approximately 2 km per year into New Jersey and Long Island. are distinguished by their reddish- contrasting with darker brown and . The is increasingly reported as an indoor pest and forms with -producing on street trees. Unlike many ants, it does not display supercolonial .



Pronunciation
How to pronounce Lasius emarginatus: /ˈleɪ.si.əs ɛˌmɑr.dʒɪˈneɪ.təs/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
measure 3–5.5 mm and are distinguished by a reddish or brownish-red contrasting with a and . Males are uniformly brown and larger at 7–14.5 mm; females () are 7–10 mm with the same color pattern as workers. The can be reliably separated from closely related Lasius species through morphometric analysis, with identification confidence of 93–99% when using combined genetic and morphological approaches.
Images
Habitat
to and temperate regions of western Eurasia. In its North range, occupies urban environments including parks, street trees, and indoor spaces of multi-story buildings. Has been observed nesting above ground level in taller buildings in Manhattan.
Distribution
to the Western Palearctic, including Europe, the Caucasus, and Asia Minor. to North America: first detected in New York City in 2011, now established throughout Manhattan and spreading at 2 km/year into New Jersey and Long Island. Climate matching suggests potential for expansion across the eastern United States from Massachusetts to Georgia.
Seasonality
occur between June and August.
Diet
. Forms with -producing pests of street trees.
Life Cycle
may live up to 30 years; live approximately 3 years. Colony founding occurs through independent foundation or pleometrosis (multiple queens cooperating initially, with workers eventually eliminating all but the queen).
Behavior
Not aggressive toward humans but will attack or competing colonies to expand territory. are not supercolonial—neighboring nests show aggression rather than the reduced aggression typical of many .
Ecological Role
Forms mutualistic relationships with -producing on street trees, potentially facilitating pest . Has become a urban in New York City despite its relatively minor role in .
Human Relevance
Increasingly reported as an indoor pest in urban buildings. Subject of scientific interest as a rapidly spreading with potential for broad eastern North expansion.
Similar Taxa
- Lasius platythoraxSimilar and overlapping range; distinguished by different swarming times, nest preferences, and morphometric characters. F1 hybrid Lasius nigroemarginatus occurs between these two .
- Lasius nigerHistorically confused due to superficial similarity; excluded as parental of L. nigroemarginatus based on morphometric and phenological data.
Sources and further reading
- BugGuide
- Wikipedia
- GBIF taxonomy match
- iNaturalist taxon
- NCBI Taxonomy
- Catalogue of Life
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- The ManhattAnt: Identification, distribution, and colony structure of a new pest in New York City, Lasius emarginatus
- The ManhattAnt: identification, distribution, and colony structure of a new pest in New York City, Lasius emarginatus
- Lasius nigroemarginatus Forel, 1874 is a F1 Hybrid between L. emarginatus (Olivier, 1792) and L. platythorax Seifert, 1991 (Hymenoptera, Formicidae)