Holarctic
Guides
Orthosia
early spring millers
Orthosia is a genus of owlet moths (Noctuidae) established by Ferdinand Ochsenheimer in 1816. Adults are active during winter and early spring, earning the group the common name "early spring millers." The genus includes notable species such as the Hebrew character (O. gothica), the common Quaker (O. cerasi), and the speckled green fruitworm moth (O. hibisci). Species in this genus typically have a single generation per year, with adults emerging from overwintering pupae.
Osmiini
mason bees, leafcutter bees, resin bees
Osmiini is a tribe of solitary bees within the family Megachilidae, comprising approximately 19 genera and at least 1,000 described species. Members are commonly known as mason bees, leafcutter bees, and resin bees, reflecting their diverse nest construction behaviors. The tribe exhibits considerable diversity in nesting ecology, with species utilizing preexisting cavities in dead wood, hollow stems, rock crevices, empty snail shells, or excavated soil burrows. Nesting materials vary by lineage and include chewed leaves, mud, resin, and combinations with pebbles or sand grains. Pollen foraging strategies range from strict oligolecty on single plant genera or families to broad generalization across numerous plant families.
Osmoderma
Typical Hermit Beetles, Hermit Beetles
Osmoderma is a genus of scarab beetles in the subfamily Cetoniinae, commonly known as hermit beetles. The genus has a Holarctic distribution, with species found across Europe, parts of Asia, and North America. Several European species, particularly O. eremita and O. barnabita, are of significant conservation concern due to habitat loss and are protected under the EU Habitats Directive. The genus is characterized by its dependence on tree hollows for larval development, making it highly vulnerable to forest management practices that remove dead wood and veteran trees.
saproxylicconservationHabitats-Directivetree-hollowsveteran-treesindicator-speciesumbrella-specieswood-mouldCetoniinaeScarabaeidaeHolarcticEuropeNorth-Americathreatened-speciesdead-woodforest-managementcitizen-sciencedetection-dogsex-situ-breedingpollardingtraditional-agricultural-landscapesmetapopulationhabitat-fragmentationold-growth-forestbroad-leaved-treesoaklimewillowbeechorchardshedgerowsurban-parkspheromone-monitoringradio-trackingphoretic-mitesScopoli-1763Le-Peletier-&-Serville-1828O.-eremitaO.-barnabitaO.-eremicolahermit-beetleOswaldia
Oswaldia is a genus of tachinid flies established by Robineau-Desvoidy in 1863. The genus comprises approximately 20 described species distributed across the Holarctic region. As members of the family Tachinidae, these flies are parasitoids, though specific host associations for most Oswaldia species remain poorly documented. The genus is classified within the tribe Blondeliini, subfamily Exoristinae.
Otiorhynchus rugifrons
Strawberry Root Weevil
Otiorhynchus rugifrons is a weevil species in the family Curculionidae, commonly known as the Strawberry Root Weevil. It is part of a large genus of root-feeding weevils, many of which are significant agricultural pests. The species has been documented across parts of North America and northern Europe. Like other Otiorhynchus species, adults are flightless and nocturnal.
Oxymirini
Oxymirini is a tribe of longhorn beetles (Cerambycidae) in the subfamily Lepturinae. The tribe contains a small number of genera, with Oxymira being the most notable. Members of this tribe are associated with coniferous forests and are characterized by their distinctive morphology within the flower longhorn group. The tribe has a primarily Holarctic distribution, with species found across northern regions of Eurasia and North America.
Oxypodini
Oxypodini is a tribe of small rove beetles within the family Staphylinidae, subfamily Aleocharinae. The tribe comprises more than 50 genera and approximately 580 described species. Members are distributed across the Holarctic region, with particular diversity in the Palaearctic. Several genera, including Amarochara, Ilyobates, Tectusa, and Porocallus, have been subject to recent taxonomic revision.
Ozyptila
Leaflitter Crab Spiders
Ozyptila is a genus of small crab spiders (Thomisidae) established by Eugène Simon in 1864. The genus comprises approximately 103 species distributed across Africa, Europe, North America, and Asia. Members are ground-dwelling spiders with a distinctive pear-shaped, elevated carapace and short, spiny forelegs. They are frequently mistaken for the related genus Xysticus but are generally smaller in body size.
Pachyta
Pachyta is a genus of longhorn beetles (Cerambycidae) in the subfamily Lepturinae, tribe Rhagiini. The genus contains approximately 12 described species distributed across the Holarctic region. Members of this genus are associated with coniferous forests and share the characteristic short antennae and compact body form typical of the Rhagiini.
Pachyta lamed
Pachyta lamed is a Holarctic long-horned beetle (Cerambycidae) in the subfamily Lepturinae. The species occurs across northern Eurasia and North America, with two recognized subspecies: P. lamed lamed (Eurasian) and P. lamed liturata (North American). Adults are associated with coniferous trees, particularly spruce. Larvae develop in dead or decaying conifer wood, completing development over multiple years.
Pachyta lamed liturata
Pachyta lamed liturata is a subspecies of longhorned beetle in the family Cerambycidae. It belongs to a Holarctic species complex associated with coniferous forests. The parent species Pachyta lamed has a transcontinental distribution across northern regions of North America, Europe, and Asia. As a member of the subfamily Lepturinae, it shares the flattened body form typical of flower-visiting longhorned beetles, though specific ecological details for this subspecies remain poorly documented.
Pamphilius
leaf-rolling sawflies
Pamphilius is a genus of approximately 115 species of leaf-rolling sawflies in the family Pamphiliidae. Adults are typically 10–15 mm in length with black bodies, yellowish spots on the head, yellow legs, and transparent wings. Larvae are solitary or colonial leaf-rollers that feed on various deciduous trees and shrubs. The genus has a Holarctic distribution, occurring in North America and Eurasia.
Panagaeus
Holy Ground Beetles
Panagaeus is a genus of ground beetles (Carabidae) comprising approximately 15 described species. The genus has a broad geographic distribution spanning the Holarctic, Near East, North Africa, Central America, and South America. Species within this genus are commonly referred to as "Holy Ground Beetles" due to distinctive markings on the elytra that resemble crosses or other symbolic patterns. The genus was established by Latreille in 1802 and belongs to the subfamily Panagaeinae.
Pandemis
Leafroller moths
Pandemis is a genus of tortricid moths in the tribe Archipini, commonly known as leafroller moths. The genus comprises approximately 60 described species distributed across the Holarctic region, with particular diversity in Eurasia. Several species are recognized as agricultural pests, notably Pandemis cerasana (barred fruit-tree tortrix) and Pandemis pyrusana (Pandemis leafroller), which damage fruit trees and other woody plants. Larvae typically feed on leaves of deciduous trees and shrubs, often rolling or folding leaves for shelter.
Panurginus
mining bees
Panurginus is a genus of mining bees in the family Andrenidae, with more than 50 described species distributed across the Holarctic region. Species occur in diverse habitats including alpine zones of Central Europe, the Siberian taiga, and steppe regions of Central Asia. Some species, such as P. herzi and P. montanus, are morphologically very similar and require quantitative measurements for reliable identification. The genus exhibits variable pollen host specialization, with individual species ranging from narrow specialists to broad generalists.
Panzeria
Panzeria is a genus of tachinid flies (Diptera: Tachinidae) in the tribe Ernestiini, containing approximately 80 described species distributed across the Holarctic region. Species within this genus are parasitoids, with at least one species, Panzeria ampelus, documented as an occasional parasitoid of agricultural pest Lepidoptera. The genus was established by Robineau-Desvoidy in 1830 and includes species described by numerous dipteran taxonomists across the 19th and 20th centuries.
Parachaetocladius
non-biting midges
Parachaetocladius is a genus of non-biting midges in the subfamily Orthocladiinae of the family Chironomidae, established by Wolfgang Wülker in 1959 and revised in 2020. The genus contains approximately 10 described species distributed across the Holarctic region, including both Palaearctic and Nearctic representatives. Species are typically associated with lotic freshwater habitats, particularly sandy substrates in springs and groundwater-fed streams. The genus is distinguished from related orthocladiine genera primarily through adult male genitalic characters, particularly features of the hypopygium.
Parasyrphus
Bristleside Flies
Parasyrphus is a genus of hoverflies (Syrphidae) comprising 31 described species distributed across the Holarctic region. Adults are small to medium-sized (5.6–11 mm) with characteristic yellow abdominal markings. The genus exhibits notable larval trophic diversity: most known larvae are aphid predators on trees, while at least two species (P. nigritarsis and P. melanderi) are specialist predators of leaf beetle eggs and larvae. This dietary specialization is unusual among syrphid flies and involves sophisticated chemical ecology where predators exploit prey defensive secretions as foraging cues.
Patrobina
Patrobina is a subtribe of ground beetles (Carabidae) within the tribe Patrobini, established by Kirby in 1837. Members of this subtribe are small to medium-sized beetles associated with moist, often riparian or wetland habitats. The subtribe includes genera such as Patrobus and others, though the precise generic composition has been subject to taxonomic revision. Patrobina beetles are part of the diverse carabid fauna that contributes to predatory control of invertebrate populations in temperate ecosystems.
Patrobus cinctus
Patrobus cinctus is a species of ground beetle in the family Carabidae. It has a Holarctic distribution, occurring across Europe, Northern Asia (excluding China), and North America including Alaska and Canada. Like other ground beetles, it is a ground-dwelling predator sensitive to soil disturbance, making it a useful bioindicator of agricultural practices.
Patrobus foveocollis
Patrobus foveocollis is a ground beetle species in the family Carabidae, characterized by its Holarctic distribution spanning Europe, Northern Asia, and North America. The species belongs to the subfamily Patrobinae, a group of ground beetles often associated with moist habitats. Like other Patrobus species, it is sensitive to soil disturbance and agricultural practices.
Pediacus fuscus
Pediacus fuscus is a species of flat bark beetle in the family Cucujidae. The species has a Holarctic distribution, occurring in Europe, Northern Asia (excluding China), and North America. As a member of the Cucujidae, it belongs to a group of beetles adapted to living under bark and in decaying wood.
Pedilophorini
Pedilophorini is a tribe of minute moss beetles (family Byrrhidae) established by Casey in 1912. Members are classified within the subfamily Byrrhinae and are characterized by small body size and association with mossy microhabitats. The tribe contains multiple genera distributed primarily in the Holarctic region. These beetles are part of the diverse Byrrhoidea superfamily within the Elateriformia infraorder.
Pelecocera
Pelecocera is a Holarctic genus of small hoverflies (Syrphidae) comprising approximately 14 species. Adults are typically black and yellow or orange, found primarily in heathland and conifer forest habitats. Larval biology has been historically poorly known, but recent studies confirm mycophagy in at least two species, with larvae developing inside the hypogean fungal fruit bodies of Rhizopogon luteolus.
Pelochrista
Pelochrista Moths
Pelochrista is a Holarctic genus of tortricid moths in the subfamily Olethreutinae. The genus contains numerous species distributed across the Palearctic and Nearctic regions. Members are small to medium-sized moths with typical tortricid wing posture at rest. The genus is taxonomically well-established with records from Europe, North America, and Asia.
Pelochrista dapsilis
Pelochrista dapsilis is a species of tortricid moth in the family Tortricidae, subfamily Olethreutinae, and tribe Eucosmini. It was described by Carl Heinrich in 1929. Like other members of its genus, it is a small moth with typical tortricid morphology. The species is part of a large and diverse genus of tortricid moths found primarily in the Holarctic region.
Pelophila borealis
boreal mud-loving beetle
Pelophila borealis is a species of ground beetle in the subfamily Nebriinae, first described by Gustaf von Paykull in 1790. It is a small, shiny black beetle measuring 9.5–10.1 mm in length. The species has a Holarctic distribution, occurring across northern Eurasia and North America.
Pemphredon
Typical Aphid Wasps, Aphid Wasps
Pemphredon is a genus of small to medium-sized solitary wasps in the family Crabronidae, commonly known as aphid wasps. The genus contains approximately 37 recognized species distributed across the Holarctic and northern Oriental regions. Females are specialized predators of aphids, which they hunt to provision nest cells for their larvae. These wasps are considered beneficial insects in agricultural and garden settings due to their role in aphid population control.
Penthetria
March flies
Penthetria is a genus of March flies (family Bibionidae) established by Meigen in 1803. Species in this genus have been documented in forest ecosystems, with at least one species, Penthetria holosericea, studied for its role in litter decomposition. The genus has a Holarctic distribution with records from Europe and North America. Males of some species exhibit brachypterous (shortened) wings.
Periclistus
Periclistus is a genus of micro-hymenopteran gall wasps (Cynipidae) comprising at least 17 described species. These wasps are obligate inquilines that occupy galls induced by other cynipid genera on plants in the rose family (Rosaceae), particularly roses (Rosa). Unlike gall inducers, Periclistus species have lost the ability to initiate galls but retain the capacity to modify existing gall tissue, inducing nutritive tissue for their own larvae. The genus exhibits a phylogenetic divide between Palaearctic and Nearctic clades, with host specificity ranging from specialists to generalists across different species.
Perineurini
Perineurini is a tribe of sawflies within the family Tenthredinidae. Members of this tribe are small to medium-sized sawflies that feed on various plants. The tribe is not well-studied, and many aspects of their biology remain poorly documented.
Phalangiidae
Phalangiid Harvestmen, Harvestmen
A family of harvestmen (Opiliones: Eupnoi) containing approximately 380 described species. The family includes the widespread and well-studied Phalangium opilio, one of the most recognizable harvestmen in temperate regions. Members are characterized by long, slender legs and a fused body lacking the narrow waist seen in spiders. The family has a primarily Holarctic distribution with some representation in Africa and other regions.
Phalangium opilio
European Harvestman, Common Harvestman, Brown Harvestman, Daddy Longlegs
Phalangium opilio is the most widespread harvestman species globally, native to Europe and much of Asia and introduced to North America, North Africa, and New Zealand. It is a synanthropic species that thrives in human-modified environments including agricultural fields, gardens, and urban green spaces. The species has become a model organism for arachnid developmental biology and comparative genomics due to its ease of laboratory culture and continuous life cycle. Adults are generalist predators and scavengers that contribute to biological pest control in agricultural systems.
Phalangodidae
Phalangodid Harvestmen
Phalangodidae is a family of small harvestmen in the suborder Laniatores, containing approximately 30 genera and more than 100 described species. Members are characterized by pedipalps armed with prominent spines and body lengths generally under 3 mm. The family is primarily distributed in the Holarctic region, with exceptional diversity in the western Nearctic, particularly California. Several species, especially in the genus Texella, are obligate cave-dwellers exhibiting troglomorphic traits such as depigmentation and reduced eyes.
Phasia aurulans
Phasia aurulans is a tachinid fly (Diptera: Tachinidae) distributed across the Holarctic region, with records from North America, Europe, and Asia. Adults measure 7–9 mm in body length. As a member of the subfamily Phasiinae, it is a parasitoid of true bugs (Hemiptera). The species was revised in a 2002 systematic treatment of the genus Phasia, which synonymized P. splendida and P. meliceris under this name.
Phenacoccus aceris
apple mealybug, maple mealybug
Phenacoccus aceris, commonly known as the apple mealybug or maple mealybug, is a widespread polyphagous mealybug species in the family Pseudococcidae. Native to Europe, it has become established across the Holarctic region including North America and Asia. The species is a significant agricultural and horticultural pest, feeding on phloem sap of numerous host plants including apple, maple, grapevine, ash, and prickly ash. Recent molecular and morphological studies have revealed that P. aceris represents a species complex containing multiple cryptic species, with taxonomic confusion arising from co-occurring putative species that cannot be reliably separated by host-plant associations alone. The species is also an important vector of grapevine viruses, transmitting six ampeloviruses and two vitiviruses.
Philodromus cespitum
Turf Running Spider, Running Crab Spider
Philodromus cespitum is a small running crab spider in the family Philodromidae, widely distributed across the Holarctic region. It is the dominant spider species in Central European fruit orchards, where it functions as an important biological control agent. Males measure 3.5–5.0 mm, females approximately 5.3 mm. Body coloration is variable, typically in shades of brown or yellow with spotted patterns. The species exhibits distinctive reproductive biology including male courtship tapping behavior and the use of genital plugs during copulation.
Philodromus rufus
white-striped running crab spider
Philodromus rufus is a Holarctic running crab spider in the family Philodromidae. Laboratory studies indicate pronounced sexual dimorphism in predatory efficiency, with adult females killing approximately six times more prey than males. The species exhibits a functional response to prey density influenced by prey activity levels. Five subspecies are recognized, including the nominate form and four regional variants in North America.
Philonthus nudus
Philonthus nudus is a rove beetle species in the family Staphylinidae, first described by Sharp in 1874. It belongs to the large genus Philonthus, which contains numerous predatory species associated with various habitats including carrion, fungi, and decaying organic matter. The species has a documented distribution across the Holarctic region, including parts of East Asia and western North America.
Pholetesor
Pholetesor is a genus of microgastrine braconid wasps containing more than 50 described species, distributed primarily in the Holarctic region. The genus was established by Mason in 1981 and includes species previously placed in Teremys, which has been tentatively synonymized. All known species are koinobiont endoparasitoids of concealed-feeding Lepidoptera larvae, with the majority specializing on leafmining and needlemining species in families such as Gracillariidae.
Phora
scuttle flies, hump-backed flies
Phora is a genus of scuttle flies in the family Phoridae, containing at least 90 described species. These small, hump-backed flies are characterized by their distinctive thoracic hump and reduced wing venation. The genus has a primarily Holarctic distribution, with records from Scandinavia and other northern regions. Members of this genus are part of the diverse Phoridae family, which includes species with varied ecological roles including decomposers, parasitoids, and associates of social insects.
Phryganea
giant caddisfly, giant caddisflies
Phryganea is a genus of large caddisflies in the family Phryganeidae, commonly known as giant caddisflies. The genus contains approximately 25–30 described species distributed across the northern hemisphere, with particularly high diversity in Europe and Asia. Larvae construct portable cases from plant material and are among the most primitive of the tube-case-building caddisflies. Adults are notable for their relatively large size compared to other caddisfly genera.
Phryganeidae
Giant Casemaker Caddisflies
Phryganeidae is a family of large caddisflies comprising approximately 16 genera and at least 80 described species. Adults are among the largest caddisflies, with wingspans reaching 40 mm or more. Larvae are aquatic case-makers, constructing distinctive cylindrical cases from plant fragments arranged in ring-like patterns. The family occurs across the Holarctic region, with species inhabiting diverse freshwater habitats from cool mountain streams to acidic bog pools.
Phtheochroa
Phtheochroa is a large genus of tortrix moths in the family Tortricidae, tribe Cochylini, subfamily Tortricinae. The genus was established by Stephens in 1829 and contains numerous species distributed across the Holarctic region, with records from Europe, North America, and other regions. Species-level identification often requires examination of genitalia, particularly in males where intraspecific variation in vesica structure has been documented.
Phtheochroa
Phtheochroa is a genus of tortricid moths in the tribe Cochylini. Species in this genus are generally small to medium-sized with relatively plain forewing patterns. The genus occurs primarily in the Holarctic region, with most species described from the Palearctic. Larval stages are associated with various herbaceous plants and shrubs.
Phylini
Phylini is a tribe of plant bugs within the subfamily Phylinae (family Miridae, order Hemiptera). The tribe contains at least 440 described species distributed across three subtribes: Keltoniina, Oncotylina, and Phylina. Members are predominantly Holarctic in distribution, with significant representation in the Palearctic, Nearctic, and Neotropical regions. The type genus is Phylus. Several genera within Phylini have been subject to recent taxonomic revision, including Wallabicoris from Australia.
Phyllodesma
Phyllodesma is a Holarctic genus of lappet moths in the family Lasiocampidae, first described by Jacob Hübner in 1820. The genus comprises approximately 17 recognized species distributed across North America, Europe, and Asia. Species in this genus are generally associated with broadleaf host plants, though specific associations vary by species. The genus is characterized by adult moths with cryptic, leaf-like wing patterns that provide camouflage against vegetation.
Phylloecus
Phylloecus is a genus of stem sawflies in the family Cephidae, first described by Edward Newman in 1838. The genus was reclassified in 2014 when Hartigia was synonymized with Phylloecus. Members of this genus are distributed across the Holarctic region, with species recorded from Europe, Asia, and North America. The genus contains approximately 30 described species.
Phyllolabis
Phyllolabis is a genus of crane flies in the family Limoniidae, subfamily Limnophilinae. The genus was established by Osten Sacken in 1877 and contains approximately 50 described species distributed across the Holarctic region. Larval and pupal stages were first described in 2017 for P. mongolica, revealing morphological similarities to Austrolimnophila, Epiphragma, and Dactylolabis. Based on immature stage characters, Phyllolabis has been reclassified as a basal lineage within Limnophilinae s.l.
Phylloneta
Phylloneta is a small genus of comb-footed spiders (family Theridiidae) containing three species and two subspecies with a Holarctic distribution. The genus was elevated from subgenus status in 2008, having formerly been considered part of Allotheridion. Species include P. impressa, P. pictipes, and P. sisyphia (with subspecies P. s. foliifera and P. s. torandae). The type species, P. pictipes, was originally described in 1884.