Nylanderia

Emery, 1906

Crazy ants

Nylanderia is a large of formicine with over 130 described and a nearly distribution, notably absent from Europe. The genus was resurrected from synonymy with Paratrechina in 2010 based on molecular and morphological reassessment. Species range from small to in size (1–4 mm) and exhibit coloration from pale to black. Several species are significant pests, including N. fulva (tawny crazy ant) and N. bourbonica, which form massive supercolonies and cause ecological and .

Nylanderia terricola by (c) Jake Nitta, some rights reserved (CC BY), uploaded by Jake Nitta. Used under a CC-BY license.

Nylanderia bruesii by (c) Jake Nitta, some rights reserved (CC BY), uploaded by Jake Nitta. Used under a CC-BY license.

Nylanderia faisonensis by (c) Even Dankowicz, some rights reserved (CC BY), uploaded by Even Dankowicz. Used under a CC-BY license.

Pronunciation

How to pronounce Nylanderia: //ˌnaɪ.lænˈdɪˌriə//

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Identification

distinguished from other Prenolepis -group genera by combination of six mandibular , macrosetae on and legs, and paired erect macrosetae on and . Some with elongated mesosoma superficially resemble Paratrechina longicornis but retain diagnostic mandibular and setal characters. identified by erect scape macrosetae combined with six mandibular teeth (vs. five in Euprenolepis and Pseudolasius). Males more difficult to distinguish due to reduced mandibular ; scape macrosetae present (absent in Paratrechina and Paraparatrechina). Several species pairs, particularly N. vividula and N. terricola, require male specimens for reliable identification.

Images

Appearance

Small to -sized , typically 1–4 mm in total length. Coloration ranges from pale to black. generally , though some show size variation. Body shape compact and with short, relatively high mesosomal regions compared to related like Paratrechina longicornis. Workers possess six mandibular , macrosetae on and legs, and paired erect macrosetae on and —features considered for the genus. have erect macrosetae on scapes surrounded by , and six (rarely seven) mandibular teeth. Males have reduced mandibular (one or two teeth) and subtriangular .

Habitat

inhabit diverse environments from deserts to rainforests, with highest diversity in forested and warmer regions. Most species are , living and foraging primarily above ground. Nests typically in leaf litter, rotting wood, and soil. Some species show specialized associations: N. arenivaga and N. phantasma occur in sandy substrates; N. microps and undescribed Australian species are small-eyed and likely subterranean or . N. bourbonica nests opportunistically in temporary sites habitable for only days or weeks. N. faisonensis occupies ephemeral locations in hardwood forest leaf litter or soil.

Distribution

Nearly distribution across all geographic regions except high-latitude areas and notably absent from Europe. occur in Nearctic, Neotropical, Afrotropical, Oriental, and Australasian regions. In the Americas, two distantly related clades: Clade I (AC1) extending from Nearctic (Utah) through Neotropical regions with Neotropical subclade in Mesoamerica, and American Clade II (AC2) exclusively Neotropical with overlapping distribution in Mesoamerica. established globally through human commerce.

Seasonality

In temperate regions, reproductive production occurs during summer, with in nests and emerging early the following spring. Nylanderia are typically among the first reproductives to after Prenolepis. Tropical species show less defined seasonal patterns, though specific data limited.

Host Associations

Nylanderia wojciki - of N. deyrupi
Nylanderia faisonensis - of N. parasitica

Life Cycle

Colony foundation details largely unknown for most . In temperate areas, reproductives produced in summer, overwinter in nest, emerge following spring. Colony size varies: N. bourbonica forms large colonies with frequent nest movements; N. faisonensis maintains small colonies of 125–150 individuals. At least three undescribed workerless known from eastern United States, representing strategy. Two inquiline species described: N. deyrupi and N. parasitica, which lack and produce only sexual offspring in colonies.

Behavior

Efficient, rapid foragers that often discover resources first and recruit nestmates quickly via chemical trails, but rarely defend resources against later-arriving competitors. Form large, nests with frequent nest movements in some . At least one species, N. flavipes, exhibits both monogynous and polygynous colony structures; of across unclear. When agitated, N. fulva produces formic acid as defensive compound. Interspecific combat documented: N. fulva secretes detoxifying cuticular substance that neutralizes fire () , enabling .

Ecological Role

Among the most abundant in many regions where they occur; fifth most frequently encountered ant genus in global leaf-litter . As , N. fulva and N. bourbonica reduce ant diversity and diversity generally. Rapid resource discovery and recruitment may influence competitive dynamics within ant . (N. deyrupi, N. parasitica, N. deceptrix) represent specialized exploitation of congeneric .

Human Relevance

Several are significant pests. N. fulva (tawny crazy , formerly Rasberry crazy ant) has spread explosively across Texas, Louisiana, and other southeastern US states, forming massive that displace fire ants and other species. cause electrical equipment damage through short-circuiting as ants swarm into component boxes. N. bourbonica and N. vaga are tramp species widespread in tropics and subtropics. N. pubens (Caribbean crazy ant) forms enormous populations in Caribbean region. Other species include N. clandestina, N. flavipes, N. guatemalensis, and N. vividula. Control efforts complicated by large colony sizes and nesting.

Similar Taxa

ParatrechinaHistorically conflated with Nylanderia; separated by lack of macrosetae and different mesosomal proportions
PrenolepisShares Prenolepis -group membership; distinguished by placement and male characteristics
ParaparatrechinaFormerly included in Paratrechina lato; differs in macrosetal patterns and lacks synapomorphic characters of Nylanderia

More Details

Taxonomic History

Nylanderia was described as subgenus of Prenolepis by Emery (1906), later placed as subgenus of Paratrechina (Emery 1925), elevated to (Wheeler 1936), synonymized with Paratrechina ( 1973, confirmed Trager 1984), and finally resurrected as valid genus by LaPolla, Brady & Shattuck (2010) based on molecular and morphological reassessment. Until 2010, most were placed in Paratrechina.

Phylogenetic Position

Within Prenolepis -group, sister to clade containing Pseudolasius, Euprenolepis, and Paratrechina stricto. Paratrechina sensu lato found to be polyphyletic, segregating into three clades: Paratrechina sensu stricto, Paraparatrechina, and Nylanderia.

Fossil Record

Two fossil known: N. pygmaea from Eocene Baltic amber and N. vetula from Miocene Dominican amber.