Introduced-species
Guides
Microplax
Microplax is a genus of true bugs in the family Oxycarenidae, established by Fieber in 1860. The genus includes species native to the Mediterranean region, with at least one species, Microplax albofasciata, having expanded its range northward to the Channel Islands and Germany, and subsequently introduced to North America. The 2012 detection in California represents the first documented occurrence in the United States.
Microprius rufulus
cylindrical bark beetle
Microprius rufulus is a small cylindrical bark beetle in the family Zopheridae, measuring approximately 3.2 mm in length. The species has a broad native distribution spanning tropical Africa, northern Africa, the Middle East, and South Asia, with introduced populations established in Germany, Cuba, USA, Malta, and the Cayman Islands. It is typically found under tree bark and exhibits attraction to light.
Mimosestes
pea and bean weevils
Mimosestes is a genus of seed beetles in the family Chrysomelidae, subfamily Bruchinae, containing approximately 13 described species. These beetles are associated with legume seeds and have been documented as introduced species in some regions, including Hawaii. The genus has been subject to phylogenetic studies examining host plant utilization patterns. Some species serve as hosts for parasitoid wasps, including the braconid Urosigalphus mimosestes.
Mirificarma eburnella
Mirificarma eburnella is a small gelechiid moth with a Palearctic distribution, now established in California as an introduced species. It is associated with leguminous host plants and has been studied as a potential biological control agent for invasive clovers. Adults are active in spring and early summer.
Mirinae
plant bugs
Mirinae is a subfamily of plant bugs within the family Miridae, comprising seven recognized tribes: Herdoniini, Hyalopeplini, Mecistoscelini, Mirini, Restheniini, Scutelliferini, and Stenodemini. Members are phytophagous true bugs with piercing-sucking mouthparts. The subfamily includes economically significant species such as the fourlined plant bug (Poecilocapsus lineatus), which causes characteristic necrotic leaf damage on numerous ornamental and agricultural plants. Some species have been introduced to new regions, including New Zealand, where they have established non-native populations.
Monarthropalpus
boxwood leafminer gall midge
Monarthropalpus is a genus of gall midges in the family Cecidomyiidae. The genus contains at least one described species, M. flavus, commonly known as the boxwood leafminer. These small flies are native to Europe and were introduced to North America, where they have become significant pests of boxwood (Buxus spp.) ornamental plants. The larvae develop as leafminers within boxwood leaves, causing characteristic yellow-orange discoloration, blistering, and gall formation that disfigures foliage.
Monelliopsis pecanis
Yellow Pecan Aphid
Monelliopsis pecanis, commonly known as the yellow pecan aphid, is a sap-feeding insect in the family Aphididae that specializes on pecan (Carya illinoinensis). It is one of two primary 'yellow' or 'honeydew' aphid species affecting pecan production, distinguished from the blackmargined aphid (Monellia caryella) by its roof-like wing posture and lack of a black marginal stripe on the wings. Outbreaks typically occur later in the growing season than those of M. caryella and can cause significant defoliation, reduced nut yield, and quality degradation. The species reproduces parthenogenetically during spring and summer, with sexual forms appearing in autumn to produce overwintering eggs.
Monocrepidius lividus
Click beetle, Wireworm beetle
Monocrepidius lividus is a click beetle in the family Elateridae, native to Europe and introduced to the eastern United States. It is one of the most frequently observed elaterid species on iNaturalist, with over 5,700 records. The species belongs to a genus that was historically conflated with related click beetle taxa, and its nomenclature has undergone revision.
Monopis longella
Pavlovski's Monopis Moth
Monopis longella is a tineid moth with a broad Palearctic and Oriental distribution, now established as an introduced species in eastern North America. Its larvae construct tubular tunnels in bird nests where they feed on keratinous materials. The species is notable for a distinctive mitochondrial genome arrangement that differs from typical lepidopteran patterns.
Monostegia
Monostegia is a genus of sawflies in the family Tenthredinidae. The genus contains at least one well-known species, M. abdominalis, commonly called the loosestrife sawfly. Adults are characterized by black heads and thoraxes with yellow legs and abdomens. The genus has a holarctic distribution, originally native to Europe and Asia but introduced to North America in the 1950s, where it has since expanded its range considerably.
Monsoma pulveratum
green alder sawfly
Monsoma pulveratum, known as the green alder sawfly, is a species of common sawfly in the family Tenthredinidae. Native to Europe, it has been accidentally introduced to North America and is documented in the Pacific Northwest region of the United States as well as parts of Canada. The species has been identified as a potential forest pest in its introduced range.
Musca autumnalis
face fly, autumn housefly
Musca autumnalis, commonly known as the face fly or autumn housefly, is a nonbiting muscid fly native to the Palearctic region that was introduced to North America in the 1940s–1950s. Adults are obligate pests of cattle and horses, feeding on ocular and nasal secretions, tears, saliva, and blood from wounds. The species exhibits pronounced seasonal population dynamics, with peak abundance in late summer and autumn, and undergoes facultative diapause in adults triggered by short photoperiod and cool temperatures. Larval development occurs exclusively in fresh cattle dung, where larvae feed on microbial flora and fauna.
Muscina pascuorum
Pasture Fly, European Scavenger Fly
Muscina pascuorum is a muscid fly native to Europe that has become established across North America. The species is closely allied to M. stabulans and M. levida. It is known to enter homes in autumn and winter, where adults accumulate on windowsills. Larvae develop in fungi, particularly woodland mushrooms, rather than in carrion or manure like many related muscids. The specific epithet 'pascuorum' refers to pastures, reflecting its original European habitat association.
Myosides
Myosides is a genus of weevils in the family Curculionidae, subfamily Entiminae. The genus was established by Roelofs in 1873 and is native to Asia. At least one species, Myosides seriehispidus, is known to have established populations in North America since 2000.
Myosides seriehispidus
Hair-banded Broad-nosed Weevil
Myosides seriehispidus is a broad-nosed weevil native to Asia that has established populations in North America since 2000. It is notable for its triploid chromosome complement and obligate parthenogenetic reproduction, meaning all individuals are female and reproduce without mating. The species is commonly known as the Hair-banded Broad-nosed Weevil.
Myrmecocephalus concinnus
Myrmecocephalus concinnus is a species of rove beetle (family Staphylinidae) in the subfamily Aleocharinae. It has an exceptionally broad geographic distribution spanning six continents, including native ranges in Africa, North and South America, Europe, and Asia, with introduced populations in New Zealand and the Galápagos Islands. The species belongs to the tribe Falagriini, a group of small to medium-sized rove beetles often associated with ant colonies or decaying organic matter.
Myrmecosaurus ferrugineus
Myrmecosaurus ferrugineus is a rove beetle (Staphylinidae: Paederinae) first described from Argentina in 1932. The species has been introduced to the southeastern United States, where it has been recorded in Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, and South Carolina. As a member of the myrmecophilous genus Myrmecosaurus, it is associated with ant colonies, though specific host relationships remain poorly documented. The species name refers to its rusty or iron-colored appearance.
Myrmica specioides
Myrmica specioides is an ant species native to the West Palearctic region that has established introduced populations in North America. It was first recorded in the eastern United States in 2013 from Wake County, North Carolina. The species was identified through morphometric comparison to type specimens and DNA barcoding. Its invasive potential and ecological impacts in North America remain subjects of discussion.
Nathrius
Nathrius is a genus of longhorn beetles in the subfamily Cerambycinae, tribe Psebiini. The genus contains three described species, including the widely distributed N. brevipennis, which has been introduced to Australia. Members are small cerambycids with reduced elytra exposing part of the abdomen.
Naupactus leucoloma
white-fringed weevil, white-fringed beetle
Naupactus leucoloma is a broad-nosed weevil native to South America that has become a globally distributed agricultural pest. Adults are flightless, parthenogenetic females outside their native range, with males occurring only rarely in Argentina, Uruguay, and southern Brazil. The species is notable for its extreme polyphagy, having been documented feeding on over 385 plant species. Larval root-feeding causes substantially more economic damage than adult folivory.
Naupactus peregrinus
Naupactus peregrinus is a species of broad-nosed weevil in the family Curculionidae, subfamily Entiminae. It belongs to the large Neotropical genus Naupactus, commonly known as "white-fringed weevils." The species has been recorded from the southeastern United States (Alabama, Arkansas, Florida) and parts of South America (Chaco, Entre Ríos in Argentina). Like other members of its genus, it is likely associated with vegetation and may have been introduced to some regions, though specific ecological details remain poorly documented.
Nemapogon variatella
Pale Corn Clothes Moth
Nemapogon variatella is a small tineid moth with a wingspan of approximately 12 mm. Native to Europe, it has been introduced to North America where established populations have been documented. The species is associated with fungal and detrital food sources, with larvae recorded feeding on bracket fungi including Coriolus versicolor, Laetiporus sulphureus, and Polyporus squamosus.
Nemastoma
harvestman
Nemastoma is a genus of small harvestmen (Opiliones) in the family Nemastomatidae, first described by C.L. Koch in 1836. Species in this genus are litter-dwelling arachnids found primarily in Eurasia, with some introduced populations in North America. The genus includes species complexes with notable morphological diversity, such as the N. bidentatum complex, which exhibits extensive subspecific differentiation and parapatric distribution patterns in Slovenia. Several species have been documented as introduced to North America, including N. bimaculatum, which has established populations in Canada.
Nemastoma bimaculatum
Gold-spotted Harvestman
Nemastoma bimaculatum is a small harvestman species native to western Europe, recognized by its distinctive coloration. It has been introduced to North America, where established populations occur in Ontario, Canada. The species was first documented in North America by LeSage (1977).
Neocochylis dubitana
Little Conch
Neocochylis dubitana, commonly known as the Little Conch, is a small tortricid moth native to the Palearctic region with introduced populations in North America. The species was originally described by Hübner in 1799 as Tortrix dubitana and has undergone several taxonomic revisions, most recently transferred from Cochylis to Neocochylis. It is a relatively well-documented species with over 800 observations on iNaturalist, reflecting both its actual abundance and the ease of identification among conch moths. The moth is associated with open habitats where its larval host plants occur.
Neocrepidodera ferruginea
European rusted flea beetle, Altise ferrugineuse européenne
Neocrepidodera ferruginea is a flea beetle in the family Chrysomelidae, native to Europe and introduced to North America. Adults are brown in color and feed on a variety of herbaceous plants, particularly grasses and composites. The species inhabits meadows and grasslands, and has been recorded from numerous host plants including Poaceae, Asteraceae, and various weeds. Larvae develop within roots and central stems of host plants. In North America, it was first documented in Ontario and Québec in the 1970s and has since spread northeastward, where it is considered a potential agricultural pest.
Neomyia cornicina
Small False Greenbottle
Neomyia cornicina is a common coprophagous muscid fly native to the Palaearctic region, with introduced populations in the Nearctic. Adults and larvae feed on cattle dung, contributing to dung decomposition. The species is frequently used as a model organism in ecotoxicological studies examining the effects of veterinary pharmaceuticals on non-target dung fauna.
Neoscona nautica
Brown Sailor Spider
Neoscona nautica, commonly known as the brown sailor spider, is an orb-weaving spider in the family Araneidae. Native to Asia and Pacific islands, it has been introduced to both the Americas and Africa. As a member of the genus Neoscona, it constructs spiral orb webs to capture flying insect prey.
Nephrotoma suturalis
tiger crane fly
Nephrotoma suturalis is a species of tiger crane fly in the family Tipulidae, first described by Loew in 1863. The species has been extensively used as a model organism in cell biology research, particularly for studies of spermatogenesis and spindle microtubule dynamics. Two subspecies are recognized: N. s. suturalis in the southeastern USA and N. s. wulpiana with a broader distribution including western North America and adventive populations in Europe and Hawaii.
Nesticodes rufipes
Red House Spider
Nesticodes rufipes, commonly known as the Red House Spider, is a cobweb spider in the family Theridiidae and the sole species in its genus. It has been introduced globally and is found on multiple continents including North America, South America, and oceanic islands. The species has been studied extensively for its predatory behavior, exhibiting a type II functional response to prey density. Research indicates that habitat complexity significantly affects its predation efficiency, with reduced capture rates in more complex environments due to prey refuge availability.
Neuroterus anthracinus
Oyster Gall Wasp
Neuroterus anthracinus is a gall wasp in the family Cynipidae that forms chemically induced leaf galls on oak trees. The species exhibits heterogony, alternating between sexual and agamic (parthenogenetic) generations that produce two distinct gall types: the oyster gall and the April-bud gall. This wasp has been widely distributed across Europe and has been introduced to North America.
Niambia capensis
African Cape Isopod
Niambia capensis is a species of woodlouse in the family Platyarthridae, first described by Dollfus in 1895. It is native to Africa, with records from South Africa and Namibia, and has been introduced to North America. This terrestrial isopod belongs to the suborder Oniscidea, which contains the familiar pillbugs and sowbugs. The species represents one of the few documented cases of transoceanic dispersal in terrestrial isopods, likely through human-mediated transport.
Niphonyx
hops angleshade
Niphonyx is a monotypic moth genus in the family Noctuidae, containing the single species Niphonyx segregata. The genus was erected by Shigero Sugi in 1982. The sole species, known as the hops angleshade, is native to eastern Asia and was introduced to the northeastern United States in the 1990s. The genus is characterized by its small size and specialized larval association with hop plants.
Niphonyx segregata
Hops Angleshade
Niphonyx segregata, known as the Hops Angleshade, is a noctuid moth native to eastern Asia. The species was introduced to the northeastern United States in the 1990s and has established a breeding population there. It belongs to the subfamily Condicinae within the diverse family Noctuidae.
Nipponoserica peregrina
Nipponoserica peregrina is a scarab beetle in the family Scarabaeidae. The species exhibits a disjunct distribution, occurring in Japan and in the eastern United States (Maryland, Massachusetts, New York, Virginia, West Virginia, and Vermont). The North American population is considered introduced. The specific epithet 'peregrina' refers to its wandering or foreign nature, reflecting its transoceanic range.
Notioplusia illustrata
notioplusia moth
Notioplusia illustrata, commonly known as the notioplusia moth, is a noctuid moth first described by Achille Guenée in 1852. Native to the Caribbean, Florida, and the Americas, it has been introduced to Australia and South Africa, where its larvae feed on Lantana camara leaves. The species has been utilized as a biological control agent for this invasive plant.
Novius koebelei
Koebele's ladybird
Novius koebelei is a ladybird beetle native to Australia, first described by Olliff in 1892. The species exhibits notable color variation, having been described as new six times after its original description due to this variation. It has been introduced to New Zealand, where it was first recorded in Auckland in 2006, and to California for biological control purposes alongside N. cardinalis, though it is not believed to persist there now.
Nylanderia flavipes
Yellow-footed Ant
Nylanderia flavipes is a small ant species in the subfamily Formicinae, native to Asia and introduced to the Nearctic region including the United States. It was previously classified under the genus Paratrechina before taxonomic revision. The species serves as a documented host for the parasitoid wasp Gollumiella buffingtoni, with workers showing unusual tolerance and active assistance toward the parasitoid's development. It is one of at least five introduced Nylanderia species established in the Nearctic region.
Nylanderia steinheili
West Indian Crazy Ant
Nylanderia steinheili is an introduced ant species in the Nearctic region, originally described by Forel in 1893 under the genus Prenolepis. It is one of at least five Nylanderia species introduced to North America from tropical regions. The species is known from the West Indies and has been recorded in the Galápagos Islands and parts of South America. Its introduced status in the Nearctic suggests potential for ecological impact, though specific biological details remain poorly documented compared to congeners like the tawny crazy ant (Nylanderia fulva).
Oberea erythrocephala
Leafy Spurge Stem Boring Beetle, Red-headed Leafy Spurge Stem Borer
Oberea erythrocephala is a slender, elongate longhorn beetle introduced to North America as a biological control agent for leafy spurge (Euphorbia esula). Adults have distinctive red heads, black eyes, and grayish-black hind wings. The species is univoltine and oligophagous, feeding and developing only on certain Euphorbia species in the subgenus Esula. It was approved for release in the United States in 1980 and has since established populations across at least fifteen states and several Canadian provinces. The beetle is considered secondary to Aphthona flea beetles in leafy spurge management due to its narrower host range.
Ochthephilum fracticorne
Ochthephilum fracticorne is a rove beetle (Staphylinidae) first described by Paykull in 1800. It belongs to the subfamily Paederinae and is characterized by the abbreviated elytra typical of the family. The species has a broad native distribution across the Palearctic and has been introduced to North America.
Octonoba
Octonoba is a genus of cribellate orb-weaving spiders in the family Uloboridae, established in 1979. The genus comprises 33 described species distributed across East Asia, with highest diversity in China, Japan, and Taiwan. Members are characterized by a carapace length exceeding 1.4 mm, distinguishing them from the related genus Purumitra. One species, O. sinensis, has been introduced to the United States.
Octonoba sinensis
Octonoba sinensis is a cribellate orb-weaving spider in the family Uloboridae. Native to East Asia, it has been introduced to the United States. As a member of Uloboridae, it lacks venom glands and instead uses a cribellum—a specialized silk-producing organ—to create sticky capture threads.
Ocypus aeneocephalus
Ocypus aeneocephalus is a species of large rove beetle in the family Staphylinidae. It is native to Europe and has been introduced to western North America, including British Columbia, Canada, and Washington State, USA. The species is part of the hyperdiverse rove beetle genus Ocypus, which contains numerous species with varied ecological roles.
Ocypus olens
Devil's Coach-horse Beetle, Devil's Coach-horse, Devil's Footman, Devil's Steed
Ocypus olens, commonly known as the Devil's Coach-horse Beetle, is a large rove beetle in the family Staphylinidae. Originally described as Staphylinus olens in 1764, this species has a long history of association with folklore and superstition across Europe, particularly in Ireland where it was known as 'Dar Daol' (the Devil's beetle). The beetle is a formidable predator with an intimidating defensive posture—raising its curled abdomen like a scorpion when threatened. In North America, it has been introduced to California where field studies suggest it may serve as a biological control agent for the brown garden snail (Helix aspersa), an agricultural pest.
Odiellus
harvestmen
Odiellus is a genus of harvestmen in the family Phalangiidae, containing approximately 17 described species distributed across Europe and introduced regions. The genus includes Odiellus spinosus, a well-studied species with a sequenced genome and documented life history. Members of this genus are characterized by relatively short legs compared to many other harvestmen and often possess distinctive body ornamentation including spines or granulations.
Odontomachus haematodus
two-spined trapjaw ant
Odontomachus haematodus is a large, aggressive species of trap-jaw ant native to South America that has established introduced populations across the southeastern United States, particularly along the Gulf Coast. The species is notable for its powerful, spring-loaded mandibles capable of rapid snapping movements used in prey capture and defense. Workers are active both diurnally and nocturnally, foraging in and around rotting wood and occasionally nesting within plants such as Aechmea aquilega. Research has documented this species as a predator of Thoropa taophora tadpoles and has identified unique queen pheromones involving dialkyltetrahydrofurans, compounds previously unknown in eusocial insects.
Oecobius amboseli
Oecobius amboseli is a species of wall spider in the family Oecobiidae, first described in 1974. Native to East Africa and Egypt, it has established introduced populations in northwestern Europe including Denmark, the Netherlands, and Belgium. As a member of the Oecobiidae, it belongs to a family known for constructing flat, circular webs on vertical surfaces.
Oecobius annulipes
Ringed Wall Spider
Oecobius annulipes is a small wall-dwelling spider in the family Oecobiidae, native to Northern Africa and introduced to Brazil, St. Helena, and Pacific Islands. This species has been studied extensively for its photoperiod-sensitive life cycle and web-building behavior. Adults are active primarily from April to early September, with complex overwintering strategies that vary based on photoperiod conditions. The species constructs characteristic flat, tangled webs on walls and structures, and has been observed capturing prey through specialized web-use behavior.
Oecobius maculatus
Oecobius maculatus is a small spider in the family Oecobiidae, commonly known as wall spiders or disc web spiders. Native to the Mediterranean region extending to Azerbaijan, it has been introduced to the United States and Mexico. The species is characterized by its flattened body form and association with human structures.