Adventive-species
Guides
Bactericera minuta
Bactericera minuta is a small psyllid species native to North America that has become adventive in South America, where it was first recorded in Colombia. It feeds on willow species (Salix), particularly Salix humboldtiana, and has been associated with phytoplasma disease symptoms in infested trees. The species was originally described in 1910 and represents one of only two Bactericera species known from South America, where the genus is not native.
Caloptilia triadicae
Chinese Tallow Leaf Miner
Caloptilia triadicae is a small moth in the family Gracillariidae, described by Davis in 2013. It is a leaf-mining specialist on Chinese tallow tree (Triadica sebifera), an invasive plant in the southeastern United States. The species is adventive (non-native) in North America and has been investigated for its potential as a biological control agent. Its seasonal abundance patterns and parasitoid associations have been studied in Florida.
Ceraticelus
dwarf spiders
Ceraticelus is a genus of dwarf spiders in the family Linyphiidae, subfamily Erigoninae. First described by Eugène Louis Simon in 1884, the genus currently contains approximately 34 species and two subspecies distributed primarily in North America, with some species occurring in Europe and Asia. The genus definition has been historically problematic due to superficial treatment of male palpal bulb morphology. Recent taxonomic work has clarified diagnostic characters through examination of the type species, C. fissiceps.
Ceraticelus artemisiae
A small dwarf spider (subfamily Erigoninae) described from southern California in 2009. Often found co-occurring with its probable sister species Ceraticelus phylax, with which it shares distinctive male palpal bulb morphology. The genus Ceraticelus is taxonomically problematic due to inadequate definition and superficial treatment of diagnostic characters.
Cercyon
water scavenger beetles
Cercyon is a genus of small water scavenger beetles in the family Hydrophilidae, subfamily Sphaeridiinae, with at least 50 described species worldwide. The genus is predominantly terrestrial despite its family name, with species frequently associated with decaying organic matter and feces. Species occur across multiple continents including North America, the Caribbean, Europe, Asia, and Africa, with some species being adventive (introduced) outside their native ranges. Taxonomic studies have revealed cryptic species complexes distinguishable only by male genitalia and DNA sequences.
Chrysolina fastuosa
Chrysolina fastuosa is a small (5.0–6.0 mm), univoltine leaf beetle native to the Palearctic Region, ranging from eastern Siberia to western Europe. First North American records document established populations in Nova Scotia, Canada and Vermont, USA, separated by over 900 km. The species is distinguished by bright metallic green coloration with blue at the elytral suture and often orange median longitudinal areas on the elytra. It feeds on Lamiaceae, particularly Galeopsis species, and has the potential to spread across the northeastern United States and southeastern Canada.
Closterotomus norvegicus
potato capsid
Closterotomus norvegicus, commonly known as the potato capsid, is a small plant-feeding bug in the family Miridae. It measures 6–8 mm in length and undergoes a distinctive color change from green in nymphs to reddish-brown in adults. The species feeds primarily on flowers, buds, and unripe fruit of various plants including potato, carrot, clover, nettle, and cannabis. Native to the Palearctic region, it has been introduced to North America as an adventive species.
Ctenarytaina
eucalyptus psyllids, blue gum psyllids
Ctenarytaina is a genus of jumping plant lice (psyllids) in the family Aphalaridae, native to Australia and associated primarily with Myrtaceae. The genus includes economically significant pest species that have been introduced to multiple continents, particularly Ctenarytaina eucalypti, which threatens eucalyptus forestry and ornamental foliage industries. Several species have established adventive populations outside their native ranges, with documented impacts in Ireland, Chile, Colombia, and other regions. The genus exhibits strong host plant associations, with most species being monophagous or narrowly oligophagous on Eucalyptus, Syzygium, and other Myrtaceae.
Ctenocallis setosa
Ctenocallis setosa is a small aphid species native to Europe, adventive in North America, and recently detected in Japan (2017–2018, 2023–2024) as the first record for Asia. It is tightly associated with Cytisus scoparius (scotch broom), a naturalized invasive shrub. The species exhibits a monoecious holocyclic life cycle with sexual morphs produced in fall for overwintering eggs and no summer host alternation.
Demotina
Demotina is a genus of leaf beetles in the subfamily Eumolpinae containing over 50 described species. The genus is native to Asia, Australia, and Oceania, with one adventive species (Demotina modesta) established in the southeastern United States. Some species are known to be parthenogenetic. One species, Demotina fasciculata, has been documented engaging in cecidophagy—feeding on plant galls induced by cynipid wasps.
Ectemnius maculosus
square-headed wasp
Ectemnius maculosus is a species of square-headed wasp in the family Crabronidae. Its native range encompasses much of the eastern United States and southeasternmost Canada. The species has been reported from outside its native range in North America, Europe, and northern Asia, though these populations may represent adventive introductions. Like other members of the genus Ectemnius, this species is a solitary wasp that provisions nests with prey for its larvae.
Errastunus
Errastunus is a genus of grass-feeding leafhoppers in the family Cicadellidae, tribe Paralimnini. The genus contains species distributed across Europe and North America, with two distinct species recognized in the Nearctic region: the native E. sobrinus and E. ocellaris, which includes both native northwestern populations and adventive eastern populations introduced from Europe. These species are readily distinguishable by male genitalia and female sternite morphology, though mitochondrial introgression between them has been documented. The genus was established by Ribaut in 1946.
Errastunus ocellaris
Errastunus ocellaris is a grass-feeding leafhopper in the tribe Paralimnini, widespread across the Palearctic region and present in North America with both native and adventive populations. In the Nearctic region, the species occurs as native populations in northwestern North America (Alaska, Yukon, Northwest Territories, British Columbia) and as adventive populations in eastern North America, where it has undergone documented range expansion from the Great Lakes region eastward since the 1960s. Molecular data confirm it as a distinct species from the native North American E. sobrinus, with which it shows evidence of mitochondrial introgression in some specimens.
Leptopterna dolabrata
meadow plant bug
Leptopterna dolabrata is a heteropteran bug in the family Miridae, measuring 8.3–9.8 mm in length. It is sexually dimorphic: males are always macropterous (long-winged), while females are mostly brachypterous (short-winged). The species feeds on developing grass seeds and is considered a pest in grass seed production. It has an extensive native range across Europe and Asia, and is adventive in North America.
Lithurgus
Woodborer Bees
Lithurgus is a genus of solitary bees in the family Megachilidae, commonly known as woodborer bees. Species in this genus excavate nesting tunnels in dead wood rather than using pre-existing cavities. They are distributed across the Mediterranean Basin, Eurasia, North Africa, and parts of Asia, with some species showing recent northward range expansion. Several species have been introduced outside their native ranges, including L. chrysurus and L. huberi in the Americas.
Melasinae
false click beetles
Melasinae is a subfamily of false click beetles in the family Eucnemidae, containing approximately 15 genera and at least 30 described species. The subfamily includes several tribes: Calyptocerini, Ceballosmelasini, Dirhagini, Epiphanini, Hylocharini, Melasini, Neocharini, and Xylobiini. Genera within Melasinae include Melasis, Hylis, Epiphanis, Xylophilus, and Isorhipis. Some species, such as Hylis olexai, have established adventive populations in the Nearctic region after originating from Western and Central Europe.
Myathropa florea
Batman hoverfly, Yellow-haired Sun Fly
Myathropa florea is a common Palearctic hoverfly in the tribe Eristalini, often called the Batman hoverfly due to the distinctive skull-like pattern on its thorax. Adults are active flower visitors from May to October and are notable for their wasp-mimicking appearance. The species has become adventive in western North America since 2005. Larvae develop in waterlogged organic detritus, particularly in tree rot holes.
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.
Ocypus
Ocypus is a genus of rove beetles in the subfamily Staphylininae, containing approximately 176 described species distributed across the Palearctic, Nearctic, and Oriental regions. The genus includes the well-known Ocypus olens (devil's coach-horse beetle), a large, predatory species with documented potential for biological control of pest snails. Several species have been introduced outside their native ranges, including O. nitens, which has established in North America and shown rapid range expansion. The genus exhibits considerable diversity in China, with numerous species described from Sichuan, Gansu, Yunnan, and other provinces.
Opatroides punctulatus
Opatroides punctulatus is a darkling beetle native to the Old World that has established adventive populations in the United States. First detected in the U.S. over 20 years ago, the species is expanding its range in the Pacific Northwest and has been confirmed in southwest Idaho. It is well adapted to Mediterranean climates and functions as a detritivore, with documented populations in stored-product environments in its native range.
Parapoynx diminutalis
Hydrilla leafcutter moth
Parapoynx diminutalis is an Asian aquatic moth in the family Crambidae, first described from southeast Asia in 1880. The species has established adventive populations in North America (first recorded Florida 1976), Central America (Panama), Africa, and Europe (United Kingdom). Larvae are aquatic and feed on submerged macrophytes, with documented development on Hydrilla verticillata, Chara vulgaris, Ottelia alismoides, Blyxa auberti, and Cyperus rotundus. Despite early interest as a biological control agent for invasive hydrilla, its generalist feeding habits precluded intentional release.
Parcoblatta caudelli
Caudell's wood cockroach, Caudell's wood roach
Parcoblatta caudelli is a small, pale-colored wood cockroach native to the eastern and central United States. Males exhibit distinctive clay-yellow and brownish-yellow coloration with fully developed tegmina. The species occupies forested habitats and has been recorded from sawmill refuse. Females were historically described as capable of flight, though subsequent observations have questioned this trait.
Philonthus jurgans
Philonthus jurgans is a rove beetle in the family Staphylinidae, first described by Tottenham in 1937. The species has been documented across Europe, Russia, Turkey, and Japan, and has been introduced to North America where it occurs in Canada and the United States. It was recently recorded as a new and adventive species in the Republic of Moldova, found in a grapevine plantation. As a member of the genus Philonthus, it likely shares the predatory habits common to this group of rove beetles.
Pithanus maerkelii
Pithanus maerkelii is a plant bug in the family Miridae. It is native to Europe and the Palearctic, with an introduced population in North America. The species feeds on grasses, sedges, and rushes, using piercing-sucking mouthparts to extract fluids from stems and reproductive structures.
Plagiognathus chrysanthemi
trefoil plant bug
Plagiognathus chrysanthemi, commonly known as the trefoil plant bug, is a small mirid bug native to the Palearctic region that has become established in North America as an adventive species. It is highly polyphagous, feeding on herbaceous plants across multiple families, with documented damage to agricultural crops including birdsfoot trefoil. The species has been identified as a pest of forage legumes in Ontario, Canada.
Psallus variabilis
Psallus variabilis is a plant bug in the family Miridae, native to the Palearctic region and adventive in North America. It feeds on sap from diverse woody and herbaceous plants including oaks, fruit trees, and berry bushes. The species has been documented across Europe, parts of Asia, and the northeastern United States.
Schizocerella pilicornis
purslane sawfly, portulaca sawfly
Schizocerella pilicornis is a sawfly in the family Argidae whose larvae are internal leaf miners of Common Purslane (Portulaca oleracea). The species was described in 1868 and is notable as the only Argidae species worldwide with endophagous larvae. Adults are small wasp-like insects with distinctive sexual dimorphism: males possess forked terminal antennal segments, while females have characteristic black markings on the thorax. The species may be adventive in North America, with its native range possibly centered in South America.
Sphaeroderma testaceum
artichoke beetle
Sphaeroderma testaceum, commonly known as the artichoke beetle, is a flea beetle in the family Chrysomelidae. It is native to Europe, North Africa, and Israel, and has been introduced to Atlantic Canada. Adults are active from late spring through early autumn and feed on leaves of thistles and related plants. The species is notable as a pest of artichokes and other cultivated thistles.
Stenarella
Stenarella is a genus of ichneumonid wasps in the subfamily Cryptinae, subtribe Osprynchotina. The genus is monophyletic and distributed across the Old World, with three major biogeographic clades corresponding to the Afrotropical, Palearctic, and Oriental–Australasian regions. Eighteen species are currently recognized, twelve described as new in a 2025 phylogenomic revision. Species are ectoparasitoids of aculeate Hymenoptera that construct nests using mud or earth.