Univoltine
Guides
Phyciodes orseis
California Crescent, Orseis crescentspot
Phyciodes orseis is a small nymphalid butterfly endemic to western North America, with its core range in northern California and Oregon. It inhabits mountain valleys, meadows, and stream canyons, where it has been documented as part of ecosystem monitoring efforts on the Fremont-Winema National Forests. The species has experienced range contraction, with historical records from the San Francisco Bay Area now considered mislabeled or representing extirpated populations.
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 trimaculatus
Rose Shoot Sawfly
Phylloecus trimaculatus, commonly known as the rose shoot sawfly, is a stem sawfly in the family Cephidae. Adults emerge in late April and oviposit inside the stems of Rosa and Rubus species. Larvae feed within host stems throughout the summer before dropping to the ground to overwinter. The species occurs from southern Canada through the eastern United States to the Great Plains.
Phyllonorycter apparella
Aspen Leaf Blotch Miner, Aspen Leaf Blotch Miner Moth
A small leaf-mining moth in the family Gracillariidae with a wingspan of 8.5–10 mm. Larvae create blotch mines on aspen and related poplar species, with each mine housing a single larva. The species has one generation per year and is found across most of Europe, Turkey, and North America.
Phyllonorycter nipigon
Balsam Poplar Leaf Blotch Miner
Phyllonorycter nipigon is a small leaf-mining moth in the family Gracillariidae. The species is widespread across northern North America, with larvae that create blotch mines in leaves of various Populus species. Adults are active in late summer and fall, with one generation per year. The species is named after Lake Nipigon in Ontario, Canada.
Phytomyza glabricola
inkberry holly leafminer
Phytomyza glabricola is a leaf-mining fly in the family Agromyzidae, endemic to the eastern United States. The species exhibits host-associated divergence on two sympatric holly species, Ilex glabra and I. coriacea, with populations on each host showing substantial genetic divergence and reproductive isolation. Development time differs dramatically between host races: 2-4 weeks with multiple generations per year on I. glabra versus 9-10 months with a single generation per year on I. coriacea. Despite these differences, adults from both hosts emerge synchronously in mid-January to mid-February. The species provides a well-documented case of ecological speciation via host shift.
Phytomyza ilicis
holly leaf miner, European Holly Leafminer
Phytomyza ilicis is a small agromyzid fly whose larvae create distinctive pale leaf mines in European holly (Ilex aquifolium). Native to Europe, it has been introduced to western North America where it became a significant pest of ornamental holly. The species is univoltine, with highly synchronized phenology: adults emerge in late spring to oviposit into the soft tissue of newly expanding leaves, and larvae feed internally until completing development the following spring. It has been extensively studied as a model system for understanding population regulation, density dependence, and multi-trophic interactions including parasitism and predation.
Picromerus
Picromerus is a genus of predatory shield bugs in the family Pentatomidae. Species in this genus are predatory throughout their life cycle, feeding primarily on lepidopteran larvae and other soft-bodied insects. Several species, particularly P. bidens and P. lewisi, have been studied extensively for their potential as biological control agents against agricultural and forest pests. The genus exhibits specialized adaptations for predation, including well-developed olfactory systems for locating prey and host plants.
Picromerus bidens
spiny shieldbug, spiked shieldbug
Picromerus bidens is a predatory shield bug in the family Pentatomidae, notable for its large size and distinctive spiny pronotal projections. It is univoltine, with summer dormancy (aestivation) ensuring synchronization of its life cycle with seasonal conditions. The species is native to the Palaearctic region but has been introduced to North America, where it has established populations. Both adults and nymphs are predatory, feeding primarily on insect larvae, and the species has been investigated as a potential biological control agent.
Pieris virginiensis
West Virginia White, Toothwort White
Pieris virginiensis, the West Virginia White, is a small white butterfly endemic to moist deciduous forests of eastern North America. The species is univoltine, with adults active for approximately one month in early spring (April–May). It is threatened by habitat loss, forest fragmentation, and particularly by the invasive plant Alliaria petiolata (garlic mustard), which females mistakenly oviposit on due to chemical similarity with native host plants; larvae cannot survive on this toxic invasive. Population declines of 10–70% have been documented across its range.
Pima albiplagiatella
White-edged Pima Moth, Beach Pea Borer
A small snout moth with a wingspan of approximately 20 mm, described by Alpheus Spring Packard in 1874. The species has one generation per year. Larvae are specialized feeders on Astragalus and Lathyrus species (legumes), with documented hosts including Astragalus allochrous, A. thurberi, A. wootonii, and unspecified Lathyrus species.
Pissodes nemorensis
Deodar weevil, Eastern pine weevil
Pissodes nemorensis is a univoltine true weevil in the family Curculionidae, commonly known as the deodar weevil or eastern pine weevil. It is a significant forest pest in North America, particularly in the southeastern United States, where adults and larvae feed on phloem of coniferous trees. The species acts as a vector for pitch canker fungus (Fusarium moniliforme var. subglutinans) and is associated with blue stain fungi including Leptographium procerum and Ophiostoma piceae. Seasonal activity varies geographically: southern populations are primarily active in autumn and winter, while northern populations are active in spring.
Plagiomimicus spumosum
Frothy Moth
Plagiomimicus spumosum, commonly known as the frothy moth, is a noctuid moth described by Augustus Radcliffe Grote in 1874. It has a transcontinental distribution across North America, from southern Canada to the United States. The species is univoltine, with adults active in mid-summer. Larvae are seed-feeding specialists on sunflower (Helianthus annuus), burrowing into the flower heads to consume developing seeds.
Plebejus anna
Anna's blue
Plebejus anna, commonly known as Anna's blue, is a North American butterfly species in the family Lycaenidae. It was formerly considered conspecific with the northern blue (Plebejus idas) but is now recognized as a distinct species. The butterfly exhibits sexual dimorphism in wing coloration and is univoltine, with adults active during summer months.
Podmosta
spring stoneflies
Podmosta is a genus of spring stoneflies in the family Nemouridae, comprising approximately six described species distributed across northern North America and the Russian Far East. The genus is notable for its adaptation to cold climates, including documented embryonic diapause in at least one species. Adults are active in spring, with nymphal development occurring primarily during winter months.
Podmosta macdunnoughi
maritime forestfly
Podmosta macdunnoughi is a small nemourid stonefly distributed across glaciated regions of eastern Canada and northern New England. The species exhibits a univoltine life cycle with adults emerging in late April and early May. A distinctive embryonic diapause delays egg hatching until September, with nymphs active through winter and growth resynchronizing before emergence.
Polites draco
Draco Skipper, Rocky Mountain Skipper, Dragon Skipper
Polites draco, commonly known as the Draco Skipper or Rocky Mountain Skipper, is a small butterfly in the family Hesperiidae. It is distributed across the Rocky Mountain region from Arizona north to the Yukon Territory. The species has one generation per year, with adults active from June to early August. Its larvae feed on grasses, while adults visit flowers for nectar.
Ponometia semiflava
Half-yellow Moth, Yellow-cloaked Midget
Ponometia semiflava, commonly known as the Half-yellow Moth or Yellow-cloaked Midget, is a small noctuid moth with a wingspan of 14–24 mm. It inhabits dry open habitats across much of North America, from the Atlantic coast to the southwestern United States and north into Canada. Adults are nocturnal and active primarily from spring through summer, with timing varying by latitude. The species has one generation per year.
Potamanthidae
Hackle-gilled Burrower Mayflies
Potamanthidae is a family of burrowing mayflies comprising approximately 23 species across three to four genera (Anthopotamus, Potamanthus, Rhoenanthus, and Stygifloris). Larvae are fossorial, inhabiting interstitial spaces in gravel and pebble substrates of streams and rivers, and possess distinctive mandibular tusks used for excavation and defense. Adults are aerial and short-lived. The family has a disjunct distribution spanning North America and East Asia.
Prays atomocella
hop-tree ermine moth, Hoptree Borer Moth
Prays atomocella is a small moth in the family Praydidae, known from the central and south-central United States. Adults are active from spring through summer, with a single annual generation. The species is notable for its specialized larval association with Ptelea trifoliata (hop-tree), where larvae feed inside new shoots before pupating in cocoons.
Prionapteryx indentella
buffalograss webworm
Prionapteryx indentella is a crambid moth commonly known as the buffalograss webworm. The species is endemic to the Great Plains of North America, with confirmed records from Kansas and Texas. It completes one generation annually, with adult activity occurring from August through September. The larval stage is a specialist feeder on Bouteloua dactyloides (buffalograss), the dominant native grass of shortgrass prairie ecosystems.
Procystiphora
Procystiphora is a genus of gall midges (Cecidomyiidae) that induce galls in bamboo culms and branchlets. The genus is notable for possessing an inverted ovipositor—the first documented case in Diptera—where the ovipositor is dorsoventrally reversed relative to the typical orientation. Species have been described from Japan and China, where they develop within galls on Sasa and Phyllostachys bamboos respectively.
Profenusa
oak mining sawflies, birch leafmining sawflies
Profenusa is a genus of leaf-mining sawflies in the family Tenthredinidae. Species in this genus are primarily associated with trees in the genera Quercus (oaks) and Betula (birches), though at least one species, P. japonica, has been documented on Rosa multiflora. Larvae are internal leaf miners that feed on mesophyll tissue, creating blotch mines. Several species are economically significant as forest and urban pests, including the invasive P. pygmaea in Kazakhstan and P. thomsoni in North America.
Profenusa alumna
red oak leaf-mining sawfly
Profenusa alumna is a leaf-mining sawfly in the family Tenthredinidae. It is univoltine, completing one generation per year. Larvae feed as leaf miners within red oak leaves, creating blotch mines. The species is closely associated with red oak (Quercus rubra) in forested habitats. Pupation occurs in soil.
Prosena siberita
Prosena siberita is a tachinid fly with a distinctive elongated proboscis that folds beneath the body. Adults feed on nectar and pose no threat to humans or plants. The species was introduced to the United States in 1925 as a biological control agent targeting scarab beetle larvae, particularly the Japanese beetle. It has established populations across a broad geographic range spanning Eurasia, Australasia, and North America.
Protoboarmia porcelaria
Porcelain Gray, Dash-lined Looper
Protoboarmia porcelaria is a Geometrid moth commonly known as the Porcelain Gray or Dash-lined Looper. Adults are medium-sized with brown-gray wings marked by crossed curved lines and a distinctive black blotch. The species occurs throughout North America except the far north, with one generation annually in northern regions and two in southern areas. Larvae feed primarily on conifer foliage and overwinter in their penultimate instar stage.
Pryeria
Pryeria is a genus of zygaenid moths native to southeastern Asia, with three described species. The genus gained attention when Pryeria sinica was discovered in Virginia and Maryland in 2002, representing a new invasive pest of ornamental Euonymus shrubs in North America. The larvae are gregarious feeders that create distinctive marginal notches on leaves.
Pryeria sinica
euonymus leaf notcher, euonymus defoliator moth
Pryeria sinica is a univoltine zygaenid moth native to East Asia, introduced to the United States in 2002 where it has established populations in Maryland and Virginia. The species is a specialist herbivore of Celastraceae, particularly Euonymus species, where larvae feed gregariously and create distinctive marginal notches on leaves. Adults are diurnal wasp mimics with clear wings and aposematic coloration. The species has been reported more recently in the United Kingdom.
Psaphida resumens
Figure-eight Sallow
Psaphida resumens, commonly called the figure-eight sallow, is a species of owlet moth in the family Noctuidae. It is an early spring-emerging species with adults active from March through May. The species is widely distributed across eastern and central North America, from southern Canada to Florida and west to Texas and Minnesota.
Pseudeva purpurigera
Western Straight-lined Looper, Straight-lined Looper Moth
Pseudeva purpurigera, the Western Straight-lined Looper, is a noctuid moth found across western and eastern North America. Adults display distinctive thoracic and abdominal tufts that give a 'mohawk' appearance. The species has one generation annually, with adults active in mid-summer.
Pseudiron
crabwalker mayflies
Pseudiron is a monotypic genus of mayflies containing a single described species, Pseudiron centralis. The genus is notable for its specialized psammophilous (sand-dwelling) ecology and predatory lifestyle, which is uncommon among mayflies. Larvae are active epibenthic predators that inhabit sandy substrates in river systems.
Pseudiron centralis
White Sand-river Mayfly
Pseudiron centralis is a predaceous mayfly species endemic to sandy freshwater river habitats in North America. It exhibits a univoltine summer life cycle with an extended egg stage lasting 9–10 months. Larvae are active epibenthic predators specialized for feeding on psammophilous chironomid larvae, with distinct microhabitat shifts during development: early instars occupy marginal sands, while later instars inhabit shifting sand dunes in main channel areas. The species shows low population density but also low mortality, with random dispersion patterns in mature larvae.
Pseudohermonassa bicarnea
Pink-spotted Dart
A medium-sized noctuid moth found in eastern North America, with adults active from mid-summer through autumn. The species has a single annual generation and is associated with wetland habitats where its larval host plants grow. First described in 1852, it remains relatively common across its range.
Pseudometapterus umbrosus
Pseudometapterus umbrosus is a species of thread-legged assassin bug (Reduviidae: Emesinae) native to North America. It exhibits wing dimorphism, with most individuals being micropterous (short-winged) and rare macropterous (fully winged) forms documented. The species has been studied for its life history and laboratory rearing potential.
Pseudostenophylax
northern caddisflies
Pseudostenophylax is a genus of northern caddisflies in the family Limnephilidae, containing at least 80 described species. The genus was established by Martynov in 1909 with Pseudostenophylax fumosus as the type species. Species are primarily distributed across northern regions of North America and Eurasia, with notable diversity in Japan and alpine regions. Research on Japanese species has revealed strong phylogeographic patterns linked to mountain formation and glacial history.
Pterostichus adstrictus
Upland Blackclock
Pterostichus adstrictus is a cold-adapted ground beetle with a Holarctic-circumpolar distribution, occurring across subarctic and alpine regions of North America and Eurasia. In North America it ranges from the Bering Sea coast to Newfoundland and south to Pennsylvania, Indiana, South Dakota, New Mexico, and California's Sierra Nevada. European populations were historically known only from northern peripheries (Northern Ireland, Wales, Scandinavia) until discovery in the Austrian Alps, representing a glacial relict with arctic-alpine distribution. The species exhibits stenotopic habitat specificity and has been observed to form locally dense populations despite restricted geographic occurrence.
Ptilothrix bombiformis
Hibiscus bee, Eastern digger bee, Hibiscus turret bee
Ptilothrix bombiformis is a solitary ground-nesting bee in the family Apidae, commonly known as the hibiscus bee or eastern digger bee. It is one of only two species of the genus Ptilothrix found in the United States, with a distribution centered in the eastern half of North America. The species is notable for its specialized association with mallow family plants (Malvaceae), particularly Hibiscus species, and for its distinctive nesting behavior involving water transport to excavate hard soil. Females construct turreted nest entrances and are active primarily during summer months when host plants are in bloom.
Pulvinaria innumerabilis
Cottony Maple Scale
A soft scale insect (family Coccidae) commonly known as the cottony maple scale. Adult females are small, flattened, and brown, approximately 3 mm in length. Mature females produce conspicuous white, cottony ovisacs containing up to 1,500 eggs. The species is frequently found on maple trees, particularly silver maple (Acer saccharinum), but has been recorded on numerous other woody plants. Heavy infestations can cause aesthetic damage and minor physiological stress to host plants, though established trees typically tolerate infestations well.
Pulvinaria vitis
Cottony Grape Scale, Cottony Scale
Pulvinaria vitis is a thelytokous cottony scale insect native to Europe, now established across much of the Northern Hemisphere and beyond. It is a univoltine pest of grape and peach, with adult females overwintering on host bark and producing large ovisacs containing thousands of eggs in spring. The species exhibits distinctive discontinuous growth and feeding patterns, with three nymphal instars and limited mobility after the first moult.
Pyrgus centaureae wyandot
Appalachian Grizzled Skipper
Pyrgus centaureae wyandot is a subspecies of northern grizzled skipper endemic to the Appalachian Highlands and Northern Michigan. It is a small butterfly with distinctive checkered wing patterns and low, erratic flight. The subspecies is listed as federally threatened and state endangered in Ohio and New Jersey due to habitat loss and pesticide exposure. Populations have declined significantly from insecticide spraying targeting spongy moth outbreaks.
Pyrgus ruralis
Two-banded Checkered-Skipper, Two-banded Checkered Skipper
Pyrgus ruralis is a small skipper butterfly in the family Hesperiidae, commonly known as the two-banded checkered skipper. It occurs across western North America from southern British Columbia and the Rocky Mountains south to central California, Nevada, Utah, Colorado, Arizona, and New Mexico. The species has one generation annually, with adults active from April to July. A federally endangered subspecies, P. r. lagunae (Laguna Mountains skipper), persists in a restricted range in the mountains east of San Diego, California.
Rekoa palegon
gold-bordered hairstreak
Rekoa palegon, known as the gold-bordered hairstreak, is a small butterfly in the family Lycaenidae. It ranges from Argentina through Mexico and the West Indies, with rare occurrences in southern Texas. Adults have a wingspan of 23–28 mm and are active from May through December in Mexico, with a single annual generation. The species has been documented feeding on nectar from Senecio and Eupatorium flowers.
Renia discoloralis
Discolored Renia Moth
Renia discoloralis is a litter moth in the family Erebidae, first described by Achille Guenée in 1854. It occurs in eastern North America from Missouri to southern New England, southward to at least North Carolina. The species has a single annual generation with adults active in mid-summer. Larvae are detritivores that feed on dead leaf material.
Renia nemoralis
Chocolate Renia Moth, Tardy Renia
Renia nemoralis is a litter moth in the family Erebidae, first described by Barnes and McDunnough in 1918. It is commonly known as the Chocolate Renia Moth or Tardy Renia. The species occurs across the eastern and central United States, with adults active in late season. Larvae are detritivores, feeding on dead leaves and other organic matter.
Rhagoletis cerasi
cherry fruit fly, European cherry fruit fly
Rhagoletis cerasi is a tephritid fruit fly native to Europe and Asia, and an invasive species in North America since 2016. Adults are small, dark flies with distinctive wing patterns. The species is univoltine, with larvae developing inside cherry fruits and causing significant agricultural damage. It is considered a major pest of cherry crops across its range.
Rhagoletis cingulata
Eastern Cherry Fruit Fly, North American Cherry Fruit Fly, Cherry Fruit Fly
Rhagoletis cingulata, commonly known as the eastern cherry fruit fly, is a tephritid fruit fly species native to North America and introduced to Europe. It is a significant agricultural pest of cultivated and wild cherry species (Prunus spp.), particularly sweet cherry (P. avium) and sour cherry (P. cerasus). Females oviposit into ripening fruit, and larvae develop within the pulp, causing direct crop damage. The species exhibits latitudinal variation in morphology and phenology, with European populations appearing later in the season than the native European cherry fruit fly (R. cerasi).
Rhagoletis juglandis
walnut husk fly, black walnut fly
Rhagoletis juglandis is a univoltine tephritid fruit fly that infests walnut husks, primarily in the southwestern United States and Mexico. Adults emerge in mid to late summer and feed on dew and plant sap. Females deposit eggs in batches beneath the husk surface of developing walnuts; larvae tunnel into the inner husk and feed for 3–5 weeks before pupating in soil. The species exhibits distinctive courtship behavior including male low-frequency wing vibration with infrasound, and engages in superparasitism—reusing infested hosts even when uninfested fruits are available. It is a pest of cultivated walnuts and has been introduced to Europe.
Rhagoletis mendax
blueberry maggot, blueberry maggot fly
Rhagoletis mendax, commonly known as the blueberry maggot, is a tephritid fruit fly native to eastern North America and a major pest of cultivated and wild blueberries (Vaccinium spp.) and related Ericaceae. The species completes a univoltine life cycle in most regions, with adults emerging in spring or summer to oviposit in ripening berries; larvae feed internally, destroying fruit marketability. It is closely related to the apple maggot (R. pomonella), with which it is reproductively isolated primarily through host-specific chemical cues despite morphological similarity and laboratory interfertility. Management relies on degree-day predictive models, monitoring with baited sticky traps, and targeted insecticide applications.
Rheumaptera hastata
Spear-marked Black Moth, Argent and Sable Moth
Rheumaptera hastata is a day-flying geometrid moth with distinctive black and white coloration. It is widely distributed across the Holarctic region, with well-studied populations in interior Alaska. The species is univoltine, with adults active from early June to mid-July. Larvae are external leaf feeders with strong host preferences, particularly for paper birch.
Rheumaptera subhastata
white-banded black moth
Rheumaptera subhastata is a geometrid moth occurring across the Palearctic and Nearctic realms, with a broad distribution in western North America. Adults are active in late spring and early summer, with a single annual generation. The species is one of two Rheumaptera in North America, closely related to and often confused with R. hastata.