Range-expansion
Guides
Acanthinus argentinus
Acanthinus argentinus is a small beetle in the family Anthicidae (ant-like flower beetles). The species was originally described from South America and has been documented undergoing northward range expansion into the southern United States. As a member of Anthicidae, it is likely associated with vegetation and decaying plant material, though specific ecological details remain poorly documented.
Acronicta superans
Splendid Dagger, Splendid Dagger Moth
A medium-sized noctuid moth with a 40–45 mm wingspan. Adults are active from May to August across much of eastern and central North America. The species has shown recent westward range expansion into Alberta.
Aedes vexans
inland floodwater mosquito, tomguito
Aedes vexans is a cosmopolitan floodwater mosquito native to North America, Europe, Asia, and Africa, and is now established in Australia. It is frequently the most abundant mosquito species across much of its range, particularly in northern latitudes. Females are aggressive human biters active at dusk, while males feed exclusively on nectar. The species is a documented vector for multiple pathogens including dog heartworm, Tahyna virus, and West Nile virus, and has demonstrated laboratory competence for Zika virus transmission. Its eggs survive winter in dry flood-prone soils, hatching when inundated by rainfall.
Agonum albicrus
A ground beetle in the Platyninae subfamily described by Dejean in 1828. Long thought restricted to Mount Vernon, Alabama, but subsequent surveys revealed a much broader distribution across the eastern United States. The species was not studied again until Lindroth's work in 1955 and 1966, then rediscovered in multiple states starting in 2008.
Amblyomma
Bont Ticks
Amblyomma is the third largest genus of hard ticks (Ixodidae), comprising medium to large, often ornamented species. The genus is the sole member of the subfamily Amblyomminae and exhibits its highest species diversity in the Americas, where half of all species occur. Many Amblyomma species are medically significant as vectors of human and animal pathogens, including Rocky Mountain spotted fever, ehrlichiosis, anaplasmosis, and the agent of alpha-gal syndrome. The genus likely originated between South America and Antarctica approximately 48 million years ago, with subsequent diversification and dispersal into Australian and South American Gondwana.
Amblyomma americanum
Lone Star Tick, Northeastern Water Tick, Turkey Tick, Cricker Tick
Amblyomma americanum is a three-host hard tick native to eastern North America, notable for its aggressive host-seeking behavior and expanding geographic range. Adult females are distinguished by a silvery-white star-shaped spot on the scutum, while males display white streaks or spots at the shield margins. The species is the primary vector of Ehrlichia chaffeensis and Ehrlichia ewingii, and its bite can induce alpha-gal syndrome—a delayed allergic reaction to mammalian meat. Unlike many ticks, A. americanum exhibits active horizontal movement rather than passive questing, traveling up to 9 meters in 24 hours in field conditions.
Amblyomma maculatum
Gulf Coast tick
Amblyomma maculatum, commonly known as the Gulf Coast tick, is a three-host hard tick native to the southeastern and south-central United States. The species has been expanding its range northward and westward in recent decades, with established populations now documented as far north as Virginia and west to Oklahoma. Adults primarily parasitize large mammals including cattle, deer, and humans, while immature stages feed on small mammals and ground-dwelling birds. The species is a vector of Rickettsia parkeri, the causative agent of American tick bite fever, and has been associated with tick paralysis in rare cases. Heavy infestations on livestock can cause significant economic damage through hide degradation and blood loss.
Aratus
mangrove tree crabs
Aratus is a genus of semi-terrestrial sesarmid crabs comprising at least two recognized species, with Aratus pisonii (mangrove tree crab) being the best studied. These crabs are specialized arboreal inhabitants of mangrove ecosystems throughout the Neotropics, occupying the canopy and prop root zones. The genus has gained scientific attention due to documented climate-induced range expansion along the Atlantic coast of North America, with populations establishing in salt marsh habitats beyond the historical mangrove range limit. Research on Aratus pisonii has revealed significant phenotypic plasticity in life history traits, behavior, and physiology across native and novel habitats.
Aratus pisonii
Mangrove Tree Crab
Aratus pisonii is a small sesarmid crab endemic to Neotropical mangrove forests of the Americas. It is one of the most abundant crab species in mangrove ecosystems, where it occupies the canopy and feeds primarily on mangrove leaf tissue. The species exhibits considerable life history plasticity, with morphology and reproductive investment varying across environmental gradients. It has expanded its range into salt marsh habitats in recent decades, facilitated by anthropogenic structures.
Atalopedes campestris
Field Skipper, sachem
Atalopedes campestris, commonly known as the field skipper or sachem, is a small grass skipper butterfly in the family Hesperiidae. Adults have a wingspan of 35–41 mm. Males are orange with brown edges and a large black stigma on the forewing; females are darker brown with variable lighter markings. The species has undergone significant northward range expansion in North America during the 21st century, attributed to winter warming trends associated with climate change. In 2022, the eastern North American population was designated as a separate species, A. huron (huron sachem).
Balclutha rubrostriata
Red-streaked Leafhopper
Balclutha rubrostriata is a small leafhopper species in the family Cicadellidae, commonly known as the Red-streaked Leafhopper. It has been documented undergoing rapid range expansion in Texas and southwestern Louisiana, USA. The species has also been recorded from Florida, Hawaii, Australia (New South Wales), and Iran (Hormozgan), indicating a potentially wide or expanding distribution. As a member of the genus Balclutha, it belongs to a group of microleafhoppers often characterized by colorful wing patterns.
Cemolobus ipomoeae
Cemolobus ipomoeae is a rarely encountered specialist bee in the family Apidae, tribe Eucerini. It is known for its obligate association with morning glory plants (Ipomoea), particularly Ipomoea pandurata. The species was first recorded in Mississippi in 2017, representing a significant southwestern range expansion from its previously documented distribution. As a pollen and nectar specialist, this bee plays a specific role in the pollination of its host plants.
Coleomegilla maculata
spotted pink lady beetle, spotted lady beetle, pink spotted lady beetle, twelve-spotted lady beetle
Coleomegilla maculata is a native North American coccinellid beetle widely used in biological control programs. Adults and larvae are primarily aphid predators, though this species is unusual among North American lady beetles in its facultative pollen-feeding habit—pollen may constitute up to 50% of adult diet. The species shows increasing abundance and westward range expansion while many native coccinellids are declining, possibly due to its dietary flexibility reducing competitive impacts from invasive species. Multiple subspecies exist, with C. m. fuscilabris distinguished by bright orange-red rather than pink coloration.
Coquillettidia perturbans
Cattail Mosquito
Coquillettidia perturbans is a mosquito species with a broad intercontinental distribution spanning Africa, Asia, Australia, Europe, North America, and South America. It is a documented vector of Eastern equine encephalomyelitis virus and West Nile virus, with particular significance in disease ecology due to its ability to fly long distances and feed on large mammals including humans. The species exhibits a distinctive larval adaptation: specialized siphons that pierce aquatic plant aerenchyma to obtain oxygen, allowing larvae and pupae to remain submerged and avoid surface predators and insecticides.
Ctenucha virginica
Virginia Ctenucha, Virginia Ctenucha Moth
Ctenucha virginica is a diurnal tiger moth in the family Erebidae, notable for its wasp-mimicking appearance. The species exhibits striking metallic blue-green body coloration with yellow-orange head and black to olive-brown wings. It is endemic to eastern North America with documented westward range expansion into the Canadian Rockies. Both larvae and adults are active feeders, with caterpillars consuming grasses, irises, and sedges while adults visit flowers for nectar.
Cymatia
water boatmen
Cymatia is a genus of water boatmen in the family Corixidae, comprising approximately six described species. Members are aquatic true bugs inhabiting lentic waterbodies. The genus includes the neonative species Cymatia rogenhoferi, which has shown significant range expansion across Europe and the UK since 2005. Cymatia species are characterized by their tolerance of diverse environmental conditions and strong dispersal abilities.
Dectes texanus
Dectes stem borer, Texas prick, soybean stem borer
Dectes texanus is a native North American longhorn beetle (Cerambycidae: Lamiinae) that has emerged as a significant agricultural pest of soybeans and sunflowers in the Midwestern and Great Plains regions of the United States. Adults are characterized by antennae longer than their bodies and a pale gray coloration. Larvae tunnel inside plant stems from July through October, then girdle the stem base internally before overwintering, causing pre-harvest lodging and yield losses. The species has expanded its range and pest status dramatically since the 1980s, correlating with increased soybean acreage and adoption of no-till farming practices. Originally associated with wild hosts including ragweed and cocklebur, it colonized cultivated soybeans approximately 50 years ago.
Dere thoracica
Dere thoracica is a longhorn beetle (Cerambycidae) first reported in the United States in 2021. The species was previously known from East Asia (China, Japan, Korea) before its detection in the eastern United States, where it has since undergone range expansion. As a cerambycid beetle, it belongs to a family whose larvae are predominantly wood-borers, though specific biological details for this species remain limited in published literature.
Diceroprocta azteca
Verdant Plain Flag-Bearer
A cicada species in the family Cicadidae with a documented range spanning Central America, North America, and South America. First recorded in Kansas in 2009, representing a northward range expansion from previously known southern distributions. Associated with riparian habitats, particularly where cottonwood trees occur.
Ectobiinae
wood cockroaches
Ectobiinae is a subfamily of small to medium-sized cockroaches within the family Ectobiidae, characterized by morphological diversity and taxonomic complexity. The subfamily includes numerous genera distributed across Europe, North Africa, and the Mediterranean region, with several groups showing recent northward range expansion. Taxonomic revisions have revealed extensive cryptic diversity, with new genera such as Planuncus and multiple subgenera established based on detailed morphological analysis. Some species exhibit unusual reproductive strategies including geographic parthenogenesis.
Enallagma clausum
alkali bluet
Enallagma clausum, the alkali bluet, is a narrow-winged damselfly in the family Coenagrionidae. It is native to North America with a documented range expansion westward in western Canada. The species has been studied for parasite-host dynamics involving water mites and gregarines. Its IUCN conservation status is Least Concern with a stable population.
Epipompilus aztecus
Epipompilus aztecus is a Neotropical spider wasp in the subfamily Ctenocerinae. It is naturally rare with low capture frequency despite extensive sampling effort. The species has been recorded using Malaise traps and Möerick traps (yellow and red). Its known distribution has expanded considerably in recent years through new records in South America and the United States.
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.
Eupteryx
Eupteryx is a genus of leafhoppers in the family Cicadellidae, subfamily Typhlocybinae. Species within this genus are small, plant-feeding insects with documented associations primarily with plants in the mint family (Lamiaceae) and stinging nettles (Urtica dioica). Some species, notably E. decemnotata, have undergone rapid range expansion in recent decades. The genus exhibits host-specific oviposition behavior and color polymorphism in nymphal stages.
Euthyrhynchus
Florida predatory stink bug
Euthyrhynchus is a monotypic genus of predatory stink bugs in the family Pentatomidae, subfamily Asopinae. The sole species, E. floridanus (Florida predatory stink bug), is native to the southeastern United States and has expanded its range northward in recent decades, now regularly occurring as far north as the Mid-Atlantic and New England. This carnivorous shield bug is considered beneficial in agricultural and garden settings due to its predation on pest insects.
Euthyrhynchus floridanus
Florida predatory stink bug
Euthyrhynchus floridanus, commonly known as the Florida predatory stink bug, is a carnivorous shield bug in the family Pentatomidae and the sole species in its genus. Native to tropical and semi-tropical regions of the Americas, it has expanded its range northward in recent decades due to climate warming. This beneficial insect is a generalist predator that feeds on numerous agricultural and garden pests, including caterpillars, beetle larvae, and other stink bugs. Its distinctive orange and black coloration makes it easily recognizable among predatory true bugs.
Euura lipovskyi
Azalea Sawfly
Euura lipovskyi, commonly known as the Azalea Sawfly, is a sawfly species in the family Tenthredinidae. The species was first described from the eastern United States and has undergone recent taxonomic revision, with the combination Euura lipovskyi newly proposed. Larvae are specialized feeders on Rhododendron species in section Pentanthera. The species has shown notable range expansion in recent decades, now occurring in the Pacific Northwest, Europe, and Canada.
Faxonius virilis
Northern Crayfish, Virile Crayfish
Orconectes virilis is a medium-sized freshwater crayfish native to North America, widely distributed across Canada and the northern United States. The species is notable for its well-documented behavioral ecology, including complex social hierarchies, territorial home range behavior, and sophisticated predator avoidance mechanisms. It has been extensively studied as a model organism for agonistic behavior, chemical communication, and escape response mechanics. The species is currently expanding its range westward into Alberta and shows adaptability to varying environmental conditions, though acidification poses reproductive challenges.
Glaucopsyche lygdamus
silvery blue
Glaucopsyche lygdamus, the silvery blue, is a small butterfly native to North America. It exhibits sexual dimorphism in wing coloration, with males displaying light blue uppersides and females showing dull grayish blue. The species occupies diverse habitats across western North America and Canada, and has demonstrated significant range expansion in some regions. Multiple subspecies have been described, reflecting geographic variation in morphology and ecology.
Glyphodes
mulberry pyralid moths
Glyphodes is a genus of moths in the family Crambidae, subfamily Spilomelinae, described by Achille Guenée in 1854. The genus contains multiple species distributed across tropical and subtropical regions, with some species having expanded their ranges significantly in recent decades. Several species are economically important as pests of cultivated plants, particularly mulberry (Morus spp.), jack-fruit (Artocarpus heterophyllus), and jasmine (Jasminum spp.). Glyphodes pyloalis, known as the lesser mulberry pyralid or mulberry pyralid, is the most extensively studied species due to its impact on sericulture and mulberry production globally.
Hemileuca maia
buck moth
Hemileuca maia, commonly known as the buck moth, is a saturniid moth native to eastern North America. The species has expanded its range northward in recent decades. Adults are diurnal and do not feed. Larvae feed gregariously on oak foliage and possess urticating spines capable of causing painful reactions in humans and animals. The species has one generation per year, with eggs overwintering on host twigs. Recent taxonomic research has clarified the complex evolutionary relationships within the H. maia-nevadensis species complex, elevating several previously synonymized populations to species status.
Hybosorus illigeri
Illiger's Scavenger Scarab
A small scarab beetle in the family Hybosoridae with a remarkably broad global distribution spanning the Palaearctic, Afrotropical, Oriental, Madagascan, Nearctic, and Neotropical regions. First described from North Africa in 1853, it has established populations across multiple continents and is considered introduced in the United States, where its range continues to expand. The species is associated with decomposing organic matter.
Ixodes affinis
Ixodes affinis is a hard-bodied tick species distributed across the southeastern United States, Mexico, Central America, and South America. Unlike its congener Ixodes scapularis, this species does not bite humans but serves as a competent vector for Borrelia burgdorferi sensu stricto, the causative agent of Lyme disease. Immature stages feed on birds and small mammals, while adults parasitize larger mammals including deer and dogs. Its expanding range into southeastern Virginia and association with migratory birds has raised concerns about its role in pathogen dispersal.
Latrodectus variolus
Northern Black Widow, Northern Widow
Latrodectus variolus is a venomous spider in the family Theridiidae, native to northeastern North America. It is closely related to the southern black widow (L. mactans) and western black widow (L. hesperus). The species is medically significant due to its neurotoxic venom, though bites are rarely fatal to healthy adults. It has been observed expanding its range northward beyond previously documented boundaries.
Leptoglossus clypealis
western leaf-footed bug
Leptoglossus clypealis, commonly known as the western leaf-footed bug, is a phytophagous true bug native to western North America. Adults measure 18–19 mm in length and are characterized by brown coloration with leaf-like expansions on the hind tibiae and a pale band across the wings. The species has been documented as a pest of agricultural crops, particularly almonds and pistachios, causing kernel damage and fruit drop. Its range has expanded eastward in recent decades, with genetic studies confirming populations in Texas represent native range extensions rather than recent introductions.
Lethocerus
giant water bugs, toe biters, electric light bugs
Lethocerus is a genus of large predatory aquatic true bugs in the family Belostomatidae. Members are among the largest true bugs, with some species exceeding 12 cm in length. The genus is distinguished from related genera by specific morphological features of the fore femur and parasternites. Unlike other giant water bugs, females do not deposit eggs on males' backs; instead, eggs are laid on emergent vegetation above the waterline and guarded by males. The genus shows greatest diversity in the Americas, with limited representation in Europe, Africa, Australia, and Asia.
Lipoptena cervi
Deer Ked, Deer Fly, European Deer Ked
Lipoptena cervi is a blood-feeding ectoparasitic fly in the family Hippoboscidae, commonly known as the deer ked or European deer ked. Native to Eurasia, it has been introduced to North America and is now invasive in the northeastern United States. Adults are initially winged but shed their wings after locating a host, becoming permanently attached to cervid mammals. The species is a significant nuisance to hunters, hikers, and deer processors due to its persistent biting behavior and apparent resistance to common insect repellents.
Mansonia titillans
Mansonia titillans is a neotropical mosquito species in the tribe Mansoniini. It is the most abundant Mansoniini species in central Florida phosphate regions and has shown recent northern range expansion into South Carolina. The species is distinguished by its unique underwater oviposition behavior, where females deposit eggs on the undersurfaces of aquatic plant leaves. Larval development occurs in association with floating vegetation, particularly water lettuce (Pistia stratiotes) and water hyacinth (Eichhornia crassipes).
Metrioptera roeselii
Roesel's Bush-cricket
Metrioptera roeselii, commonly known as Roesel's Bush-cricket, is a medium-sized bush-cricket native to continental Europe that has undergone significant range expansion in northern Europe since the 1980s. The species is characterized by a distinctive yellow-green coloration with a prominent yellow stripe along the lateral margin of the pronotum. It exhibits wing dimorphism, with both short-winged (brachypterous) and long-winged (macropterous) forms occurring in populations; the long-winged form is associated with range expansion. The species has been introduced to Britain and Scandinavia, with genetic evidence indicating human-mediated dispersal in some isolated populations.
Microplax albofasciata
Microplax albofasciata is a true bug in the family Oxycarenidae, native to the Mediterranean region and parts of western Europe. The species was first described by Costa in 1847 and has been documented across southern Europe, North Africa, and the Middle East. It was first recorded in North America in California in 2012, representing a recent range expansion. The specific epithet 'albofasciata' refers to a white banded pattern characteristic of this species.
Myzocallis walshii
Black-bordered oak aphid
Myzocallis walshii is a North American aphid species that has established in Europe as an invasive pest of American red oak (Quercus rubra). Native parasitoids in the northeastern Iberian Peninsula have adapted to this introduced aphid. The species has been recorded across much of North America and has spread to at least 15 European countries.
Neomallodon arizonicus
Neomallodon arizonicus is a species of longhorned beetle in the family Cerambycidae, subfamily Prioninae. Originally described by Casey in 1912 under a different name, it was later recognized as a distinct species by Skiles in 1978. The species is found in the southwestern United States and Mexico, with records from Arizona, New Mexico, and Oklahoma. It is among the larger species in the genus and is associated with oak woodland habitats, particularly Gambel oak (Quercus gambelii). Adults are attracted to prionic acid lures and exhibit distinctive searching behavior when attempting to locate pheromone sources.
Nomada
Nomad Bees, Cuckoo Bees
Nomada is one of the largest genera in the family Apidae, with over 850 species worldwide. These bees are kleptoparasites that lay eggs in the nests of other bees, primarily ground-nesting species in the genus Andrena. Adult bees lack pollen-carrying scopa and are mostly hairless, feeding on nectar but not collecting pollen for offspring. The genus name derives from the Greek word for 'roaming' or 'wandering,' reflecting their parasitic lifestyle.
Ochlerotatus taeniorhynchus
black salt marsh mosquito
Ochlerotatus taeniorhynchus, commonly known as the black salt marsh mosquito, is a floodwater mosquito species native to coastal and salt marsh habitats across the Americas. It is a significant nuisance species and disease vector, known to transmit Dirofilaria immitis (heartworm) and susceptible to Everglades virus and Eastern Equine Encephalitis. The species has been observed expanding its range and increasing in abundance following extreme weather events such as hurricanes and flooding. Laboratory studies indicate it readily feeds on both pork and cow blood through artificial membranes, with feeding preferences varying by population.
Ocypus nitens
Ocypus nitens is a large, adventive rove beetle in the family Staphylinidae, subfamily Staphylininae, native to Central Europe and now established in eastern North America. First reported from the Americas in 1944, it remained restricted to New England for decades before rapidly expanding its range after 2000. The species was first detected in Canada in 2016 through citizen science contributions to BugGuide, representing the first Canadian record. It is among the largest and most conspicuous rove beetles in its introduced range, making it relatively easy to detect.
Odontomachus ruginodis
rough-node snapping ant, rough-node trap-jaw ant
Odontomachus ruginodis is a species of trap-jaw ant native to the southeastern United States, known for its powerful spring-loaded mandibles capable of snapping shut at high speeds. The species has been observed expanding its range northward from its previously known distribution centered on the Orlando, Florida area. Research has revealed that queens of this species use unique cuticular chemical compounds—specifically dialkyltetrahydrofurans—to distinguish themselves from workers, a signaling system distinct from both other Odontomachus species and the broader class of compounds once thought universal among eusocial insects. Like other trap-jaw ants, it is an active predator with a venomous sting.
Orconectes rusticus
Rusty Crayfish
Orconectes rusticus, commonly known as the rusty crayfish, is a freshwater crayfish native to the Ohio River basin in the United States. The species has become a highly successful invasive organism in northern lakes and streams across North America, where it displaces native crayfish through aggressive behavioral dominance. Research has documented its capacity for learned associations involving predator cues, complex social recognition systems using chemical signals, and flexible spatial learning. The species' invasion success stems from a combination of behavioral traits including high aggression, broad habitat tolerance, and efficient resource utilization.
invasive-speciesaggressive-behaviorchemical-communicationfreshwater-crayfishsecond-order-conditioningecosystem-impactrange-expansionbehavioral-ecologyspecies-displacementpredator-learningagonistic-behaviorthermal-ecologydetritivorebenthic-invertebratedecapod-crustaceanGreat-Lakes-invasivebait-introductionurine-communicationself-assessmentspatial-memoryOrnithoctona
Ornithoctona is a genus of louse flies (Hippoboscidae: Diptera) comprising 12 known species, all of which are obligate ectoparasites of birds. These winged or wing-reduced flies are blood-feeding parasites found worldwide except Antarctica. Several species have been documented expanding their ranges, with Ornithoctona laticornis recently recorded in Europe (Hungary, Romania) outside its native African distribution. The genus exhibits broad host associations across multiple avian orders, with some species showing low host specificity.
Orussus
Orussus is a genus of parasitic wood wasps in the family Orussidae, comprising approximately 11 described species. These wasps are unique among woodwasps for their parasitoid lifestyle, attacking the immature stages of wood-boring beetles and other wasps. Adults are rarely encountered and have historically been poorly collected, though citizen science platforms have recently helped expand knowledge of their distribution. The genus has undergone significant taxonomic revision, now placed in its own superfamily Orussoidea within the suborder Apocrita.
Orussus minutus
Orussus minutus is a rarely collected parasitic woodwasp in the family Orussidae, native to the eastern United States. The species is notable for its significant western range expansion documented through citizen science platforms and museum collections. Previously known from only about 50 specimens mainly in the Northeast, new records from Arkansas, Iowa, Minnesota, and Manitoba extend its range hundreds of miles westward. The species is extremely uncommon in collections despite intensive trapping efforts.