Parthenogenesis
Guides
Aaroniella
loving barklice
Aaroniella is a genus of barklice in the family Philotarsidae, commonly referred to as 'loving barklice.' The genus contains more than 40 described species and was established by Mockford in 1951. Species within this genus show variation in reproductive strategies, including documented parthenogenesis in at least one species.
Aclerda
flat grass scales
Aclerda is a genus of scale insects (family Aclerdidae) commonly known as flat grass scales. Species in this genus are legless as adults, with strongly reduced 1-segmented antennae and a unique anal apparatus. They inhabit leaf sheaths of grasses in hot, dry regions. The genus includes both sexually and parthenogenetically reproducing species, with unusual cytogenetic systems including heterochromatinization of one haploid chromosome set in males of some species.
Acropsopilio
harvestman
A genus of tiny harvestmen (Opiliones: Acropsopilionidae) established by Silvestri in 1904. The genus includes several species, with *Acropsopilio neozealandiae* being endemic to New Zealand where extensive collecting has yielded only female specimens, suggesting possible parthenogenetic reproduction. Members are found in forest habitats and are among the smallest harvestmen.
Acyrthosiphon pisum
Pea aphid, green dolphin, pea louse, clover louse
Acyrthosiphon pisum, the pea aphid, is a sap-sucking hemipteran and major agricultural pest of legume crops worldwide. It is notable as the first hemimetabolous insect with a fully sequenced genome and serves as a model organism for studying aphid biology, endosymbiosis, polyphenism, and asexual reproduction. The species exhibits complex polyphenism with multiple morphs including winged and wingless parthenogenetic females, sexual males and females, and green or red/pink color morphs. Its survival depends entirely on the obligate endosymbiont Buchnera aphidicola, which provides essential amino acids lacking in its phloem sap diet.
Adelges
Adelges is a genus of conifer-feeding insects in the family Adelgidae, closely related to aphids. Members of this genus are small, sap-sucking insects that infest various fir (Abies) and hemlock (Tsuga) species. Several species are significant forest pests, notably Adelges tsugae (hemlock woolly adelgid), which has caused extensive mortality of eastern hemlock forests in North America, and Adelges piceae (balsam woolly adelgid), a pest of balsam and Fraser firs. The genus exhibits complex life cycles often involving parthenogenetic reproduction and alternating generations between winged and wingless forms.
Adelges laricis
Larch Woolly Aphid
Adelges laricis is a holocyclic adelgid with a complex life cycle involving two host genera: Picea (spruce) as primary host where galls form, and Larix (larch) as secondary host. The species exhibits extensive morphological polymorphism across five generations (Fundatrix, Migrans alata, Hiemosistens, Sexupara, Sexualis). First-instar nymphs are the only mobile stage; subsequent instars remain sessile with stylets permanently inserted. The species is a significant forest pest causing reduced tree vigor, needle damage, and mortality under chronic infestation.
Adelges tsugae
Hemlock Woolly Adelgid, HWA
Adelges tsugae, the hemlock woolly adelgid, is a small invasive sap-sucking insect native to East Asia. In eastern North America, it is a destructive pest of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana), causing extensive tree mortality and threatening forest ecosystems. The insect is named for the white, woolly wax coating that covers its egg sacs and protects the insects beneath. It reproduces asexually via parthenogenesis in North America, producing two generations per year.
Adelgidae
adelgids, woolly conifer aphids, pine aphids, spruce aphids
Adelgidae is a small family of sap-sucking insects in the order Hemiptera, closely related to aphids. Members are commonly known as "woolly conifer aphids" due to their waxy secretions and exclusive association with conifer hosts in the family Pinaceae. The family includes some of the most destructive invasive forest pests in North America, notably the hemlock woolly adelgid (*Adelges tsugae*) and balsam woolly adelgid (*A. piceae*), which have caused widespread tree mortality. Adelgids exhibit complex, multigeneration life cycles that may include cyclical parthenogenesis, host alternation, and polymorphism.
Allocyclosa
trashline orb weaver
Allocyclosa is a monotypic genus of orb-weaver spiders in the family Araneidae, containing only Allocyclosa bifurca. Originally described as Cyrtophora bifurca in 1887, it was transferred to its own genus in 1999 based on distinctive morphological features. The genus is notable for being the only Cyclosa-like species north of Mexico with a forked abdominal tip, and for its unusual reproductive biology where males are exceptionally rare.
Allocyclosa bifurca
Bifurcate Trashline Orbweaver, Forked-tail Trashline Orbweaver
Allocyclosa bifurca is a small orb-weaving spider and the sole species in its genus. Adult females measure 5.1–8.5 mm in body length and are silvery or white in color. The species is distinguished by a forked (bifurcate) projection at the rear of the abdomen—two humps shaped like the letter 'M'—giving it the Latin name meaning 'two-forked.' This is the only Cyclosa-like species north of Mexico with this forked tail structure. The spider exhibits remarkable camouflage behavior, arranging debris and egg sacs in a vertical line through its web to masquerade as bird droppings. Unusually, males are rarely observed, and females possess vestigial external genitalia with no external opening, suggesting possible parthenogenic reproduction. The species is also notable as a host for parasitic wasps that chemically manipulate its web-building behavior.
Alloxysta
Alloxysta is a genus of small parasitic wasps in the family Figitidae, subfamily Charipinae. The genus was described by Arnold Förster in 1869 and contains over 100 species with cosmopolitan distribution. Members are aphid hyperparasitoids, attacking primary parasitoids (aphidiid wasps) that develop within aphids. Some species exhibit thelytokous parthenogenesis induced by Wolbachia endosymbionts, where unmated females produce female offspring without mating.
Alsophila pometaria
Fall Cankerworm Moth, Fall Cankerworm, Inchworm
Alsophila pometaria, the fall cankerworm, is a native North American geometrid moth notable for its sexually dimorphic adults: males are winged and capable of flight, while females are wingless, flightless, and lack functional mouthparts. The species exhibits a distinctive life cycle with adult emergence in late autumn and early winter, egg-laying on tree bark, and larval feeding in spring. Caterpillars are known as "inchworms" or "loopers" due to their characteristic looping locomotion. The species is a generalist defoliator of deciduous hardwood trees and can reach outbreak densities, causing significant economic and ecological impact.
Amblyomma dissimile
Iguana Tick
Amblyomma dissimile is a hard tick (Ixodidae) with an exceptionally broad host range spanning amphibians, reptiles, mammals, and birds across the Neotropics. It is commonly known as the Iguana Tick due to frequent associations with iguanid lizards. The species exhibits a three-host life cycle and has been documented to reproduce parthenogenetically. Its distribution extends from the southern United States through Central America and South America to northern Argentina, with highest environmental suitability in the Amazon and Pantanal biomes.
Amynothrips andersoni
Alligatorweed Thrips, Alligator Weed Thrips
Amynothrips andersoni is a species of thrips in the family Phlaeothripidae, native to South America and introduced to the United States as a biological control agent against the invasive aquatic weed alligator weed (Alternanthera philoxeroides). Adults are small, shiny black insects approximately 2 mm in length. The species exhibits wing dimorphism, with both short-winged and long-winged flying forms present, though the latter is rare. Both larval and adult stages feed on alligator weed, causing leaf curling and plant stunting.
Andricus
oak gall wasps
Andricus is a large and diverse genus of gall wasps in the family Cynipidae, comprising approximately 375 species—though many are considered taxonomically dubious. These tiny wasps are obligate gall inducers on oaks (Quercus spp.), with each species typically restricted to one or a few closely related host species. The genus exhibits complex life cycles involving alternation between sexual and asexual generations, often on different oak hosts or plant organs. Andricus is the most diverse genus in the tribe Cynipini and has a cosmopolitan distribution centered on the Northern Hemisphere, with species in Europe, Asia, North America, and Central America.
Andricus brunneus
Clustered Gall Wasp
Andricus brunneus is a small oak gall wasp found along the Pacific Coast of North America. Only females of this species are known to exist, indicating reproduction occurs through parthenogenesis. The species induces distinctive round galls on white oak leaves, particularly blue oaks (Quercus douglasii). Adults emerge in autumn.
Andricus confertus
Convoluted Gall Wasp
Andricus confertus is a cynipid gall wasp endemic to California that induces distinctive pink, brain-like clustered galls on the underside of valley oak (Quercus lobata) leaves along the midrib. The species reproduces parthenogenetically, with female larvae initiating gall formation in summer and adults emerging the following spring. The galls are composite structures formed by multiple individual galls growing in close proximity.
Andricus pisiformis
Andricus pisiformis is a species of cynipid gall wasp in the tribe Cynipini, first described by Beutenmüller in 1911. Like other members of its genus, this wasp induces characteristic galls on oak trees (Quercus spp.). The species name 'pisiformis' refers to the pea-like shape of the galls it produces. As with many Andricus species, it exhibits a complex life cycle typically involving alternation between sexual and asexual generations on different oak hosts or plant parts, though specific details for this species remain incompletely documented.
Andricus quercuscalifornicus
California Gall Wasp
Andricus quercuscalifornicus is a cynipid gall wasp that induces large oak apple galls on white oaks, primarily the valley oak (Quercus lobata). The species is considered an ecosystem engineer due to its ability to manipulate plant tissue growth, creating complex microhabitats that support diverse insect communities. No male specimens have ever been recovered; reproduction occurs strictly through parthenogenesis.
Andricus quercuspetiolicola
Oak Petiole Gall Wasp
Andricus quercuspetiolicola is a species of cynipid gall wasp that induces distinctive galls on white oaks (Quercus alba). The species name reflects its biology: 'quercus' for oak and 'petiolicola' indicating its habit of forming galls on leaf petioles and midribs. Adult wasps are small and inconspicuous, while the galls they produce are the most visible sign of their presence. Like other Andricus species, this wasp has a complex life cycle typically involving alternation between sexual and asexual generations on different oak tissues, though specific details for this species remain incompletely documented.
Andricus texanus
Andricus texanus is a species of gall wasp in the family Cynipidae, a diverse group of insects that induce characteristic growths on oak trees. Like other members of its genus, this species manipulates plant tissue to form specialized structures that provide shelter and food for developing larvae. The specific gall morphology and host associations distinguish it from related Andricus species.
Aneugmenus
Aneugmenus is a genus of sawflies in the family Tenthredinidae. The genus includes at least eight described species distributed across the Holarctic and Neotropical regions. One species, Aneugmenus merida, has been studied in detail in the Venezuelan Andes, where it exhibits parthenogenesis and specialized herbivory on bracken ferns.
Anisandrus obesus
Anisandrus obesus is an ambrosia beetle native to eastern North America that specializes in boring into the sapwood of Big Tooth Aspen (Populus grandidentata). Females construct characteristic gallery systems consisting of a single entrance tunnel approximately 7 mm deep followed by two lateral tunnels parallel to the wood surface. The species maintains an obligate symbiosis with ambrosia fungi, which larvae consume without expanding parental galleries. Progeny exhibit strongly female-biased sex ratios (approximately 6:1), with only females emerging in spring to disperse and attack new hosts.
Anomopoda
water fleas
Anomopoda is a group of small aquatic crustaceans commonly known as water fleas, classified within Branchiopoda and Diplostraca. The group includes several families of ecological and scientific importance, with some species widely used as model organisms in evolutionary biology, ecology, and toxicology. Anomopods exhibit remarkable reproductive flexibility, alternating between parthenogenetic and sexual reproduction. They occupy diverse freshwater habitats across the globe and serve as critical components of aquatic food webs.
Antistrophus
rosinweed stem gall wasp
An undescribed species of cynipid gall wasp in the genus Antistrophus that induces distinctive stem-cluster galls on Silphium perfoliatum (cup plant). Like other Antistrophus species, it likely produces only female wasps through parthenogenesis, with adults emerging in fall to lay eggs in host plant stems. The galls provide shelter and food for developing larvae.
Anystis
Whirligig Mites
Anystis is a genus of predatory mites in the family Anystidae, commonly known as whirligig mites. Species in this genus are generalist predators of small arthropods, including mites, aphids, thrips, and other soft-bodied insects. They are frequently red in coloration with long legs, ranging from 500–1500 μm in size. The genus has gained attention for biological control applications, particularly Anystis baccarum, which has been documented in agricultural systems including apple orchards, raspberry crops, vineyards, and greenhouses.
Anystis baccarum
Whirligig mite
Anystis baccarum is a cosmopolitan predatory mite in the family Anystidae, commonly known as the whirligig mite. It is a generalist predator of small, soft-bodied arthropods including aphids, spider mites, thrips, and other pests in agricultural systems. Populations consist entirely of females that reproduce by thelytokous parthenogenesis. The species has been identified as a promising biological control agent in crops such as raspberry, apple, sweet pepper, and tea, though its cannibalistic tendencies and long generation time limit its effectiveness as a sole control method.
Apatania
Apatania is a genus of caddisflies in the family Apataniidae comprising at least 90 described species. The genus has a Holarctic distribution, with species recorded across Europe, Asia, and North America. Several species have been studied in detail for their larval morphology, life cycles, and behavior. Some species, including A. muliebris, are known to reproduce parthenogenetically.
Apataniidae
Early Smoky Wing Sedges
Apataniidae is a family of caddisflies (Trichoptera) commonly known as early smoky wing sedges. The family contains approximately 18 genera and at least 180 described species. Members are primarily Holarctic in distribution, with notable diversity in Europe, Asia, and North America. Larvae are aquatic and construct portable cases from mineral particles.
Aphididae
Aphids
Aphididae is a very large family of sap-sucking insects in the order Hemiptera, containing several thousand described species. Members are soft-bodied, pear-shaped insects commonly known as aphids. The family includes the majority of plant virus vectors among insects, with approximately 200 known vector species. Many species are significant agricultural pests, causing direct damage through feeding and indirect damage through virus transmission.
Aphidina
Aphidina is a subtribe of aphids within the family Aphididae, established by Latreille in 1802. It encompasses numerous genera including economically significant and xerophilous species. Members exhibit diverse life cycles, with some species amenable to genetic control methods due to their holocyclic heterogenetic reproduction. The subtribe includes species with specialized host associations, particularly on Asteraceae, Chenopodiaceae, and Amaranthaceae.
Aphidoidea
aphids, plant lice, greenflies, blackflies, whiteflies
Aphidoidea is a superfamily of small sap-sucking insects within Hemiptera, commonly known as aphids. Members possess piercing-sucking mouthparts adapted for feeding on plant phloem. The superfamily includes approximately 5,000 described species across multiple families, with Aphididae being the largest and most economically significant. Many species exhibit complex life cycles involving both sexual and parthenogenetic reproduction, often with seasonal alternation between host plants.
Aphis
Aphis is a large genus of aphids in the family Aphididae containing at least 400–600 species. The genus includes numerous significant agricultural pests, notably the soybean aphid (Aphis glycines), cotton aphid (Aphis gossypii), and apple aphid (Aphis pomi). Many species form mutualistic associations with ants (myrmecophily), exchanging honeydew for protection. Species identification within the genus often requires examination of morphological characters such as siphunculi and cauda structure.
Aphis cephalanthi
Buttonbush aphid
Aphis cephalanthi is a species of aphid in the family Aphididae, described by Thomas in 1878. The common name "Buttonbush aphid" reflects its association with its host plant, buttonbush (Cephalanthus species). Like other aphids in the genus Aphis, it is a sap-feeding insect with a typical aphid life cycle involving parthenogenetic reproduction during favorable conditions. The species is recognized in major taxonomic databases including GBIF, Catalogue of Life, and NCBI, though detailed biological studies appear limited in the available literature.
Aphis craccivora
cowpea aphid, groundnut aphid, black legume aphid
Aphis craccivora is a small, dark-colored aphid of probable Palearctic origin that has become a cosmopolitan agricultural pest. It is polyphagous but shows strong preference for leguminous plants, particularly cowpea, groundnut, and alfalfa. The species reproduces primarily through parthenogenesis, with winged forms developing for dispersal. It is a significant pest due to direct feeding damage, honeydew production that promotes sooty mold growth, and its role as a vector for multiple plant viruses.
Aphis fabae
black bean aphid, blackfly, bean aphid, beet leaf aphid
Aphis fabae is a small, soft-bodied aphid in the family Aphididae, commonly known as the black bean aphid or blackfly. It is a significant agricultural pest with a broad host range, attacking beans, sugar beet, and numerous other crops. The species exhibits a heteroecious life cycle with host alternation between a woody primary host (Euonymus europaeus, spindle tree) and herbaceous secondary hosts. It reproduces parthenogenetically during the growing season and sexually in autumn, producing overwintering eggs. The aphid is capable of rapid population increase through viviparous reproduction, and winged forms develop seasonally to facilitate migration between host plants.
Aphis glycines
Soybean Aphid
Aphis glycines, the soybean aphid, is a small (1–2 mm) invasive pest native to Asia that was first detected in North America in Wisconsin in 2000. It has since become established throughout the north-central United States, where it causes significant economic damage to soybean crops. The species reproduces rapidly and can develop extremely high densities on soybean foliage, with yield losses of up to 40% documented in heavily infested fields. Research has shown that aphid infestation can also increase plant susceptibility to other pests such as soybean cyst nematode.
Aphis nerii
oleander aphid, milkweed aphid, sweet pepper aphid, nerium aphid
Aphis nerii is a cosmopolitan aphid species in the family Aphididae, primarily associated with plants in the dogbane family (Apocynaceae), especially milkweeds (Asclepias) and oleander (Nerium oleander). The species exhibits complex reproductive strategies including parthenogenesis and viviparity, with winged and wingless female morphs. It is a significant pest of ornamental plants and a known vector of multiple plant viruses. The species has been introduced widely beyond its native range and is now found in tropical, Mediterranean, and temperate regions globally.
Aphis pomi
apple aphid, green apple aphid
Aphis pomi, the green apple aphid, is a small sap-sucking insect specialized on pomoideous host plants in the Rosaceae family, particularly apple (Malus domestica). It is autoecious, completing its entire life cycle on a single host species. The species reproduces primarily through parthenogenesis during the growing season, with sexual forms appearing only in autumn to produce overwintering eggs. It is morphologically similar to Aphis spiraecola but can be reliably distinguished by the length of the ultimate rostral segment.
Aphis spiraecola
Spirea aphid, green citrus aphid, apple aphid
Aphis spiraecola is a polyphagous aphid species described by Edith Marion Patch in 1914. It is a significant agricultural pest of citrus, apples, and numerous ornamental plants across temperate and tropical regions worldwide. The species exhibits remarkable host flexibility, colonizing over 65 plant genera across more than 20 families. It reproduces primarily through parthenogenesis across most of its range, with holocyclic populations producing sexual morphs on primary hosts Spiraea and Citrus. The species has displaced native Aphis pomi in some regions and is considered invasive in many areas where it has been introduced.
Appendiseta robiniae
Black Locust Aphid
Appendiseta robiniae, the black locust aphid, is the sole species in the monotypic genus Appendiseta. Native to North America, it has become established as an alien species in Europe, where it has adapted successfully to local conditions. In Poland, studies documented up to 11 generations per season on its host plant Robinia pseudoacacia, with females of the second and third generations showing highest fertility. The species exhibits rapid population growth capability due to its biological predispositions.
Aproceros
Aproceros is a genus of sawflies in the family Argidae, comprising ten recognized species native to eastern Asia. The genus gained international attention following the introduction of Aproceros leucopoda (elm zigzag sawfly) to Europe around 2003 and subsequently to North America in 2020. This invasive species has demonstrated rapid range expansion and significant defoliation capacity on elm trees (Ulmus spp.). Most Aproceros species remain restricted to their native East Asian ranges, with limited biological information available for the genus beyond A. leucopoda.
Aproceros leucopoda
elm zigzag sawfly
Aproceros leucopoda, commonly known as the elm zigzag sawfly, is a small sawfly native to eastern Asia (China and Japan) that has become an invasive pest in Europe since 2003 and North America since 2020. The species derives its common name from the distinctive zigzag-shaped feeding pattern created by young larvae on elm leaves. Populations are entirely female and reproduce through thelytokous parthenogenesis, enabling rapid establishment from single individuals. The species can cause severe defoliation of elm trees and has recently been documented feeding on Japanese zelkova.
Argas
Bat-ticks
Argas is a genus of soft ticks in the family Argasidae, containing 44 species across two subgenera: Argas and Persicargas. These ticks lack the hard dorsal shield characteristic of hard ticks (Ixodidae) and exhibit distinctive feeding behaviors, taking multiple short blood meals rather than prolonged single feedings. The genus includes species with exceptional longevity—Argas brumpti individuals have survived 27 years in laboratory conditions and endured eight years without feeding. Argas species serve as vectors for tick-borne pathogens including those causing tick-borne relapsing fever.
Atrusca trimaculosa
Woollybear Gall Wasp
Atrusca trimaculosa, commonly known as the woollybear gall wasp, is a cynipid gall wasp that induces distinctive round, hairy galls on oak leaves. The galls are 3–4 mm wide, covered in stiff hairs, and typically clustered on leaf surfaces. Only females of this species are known, suggesting reproduction may occur through parthenogenesis. The species is associated with several oak species including valley oak, blue oak, and Oregon oak.
Aulacorthum solani
Foxglove aphid, Glasshouse-potato aphid
Aulacorthum solani is a globally distributed agricultural pest aphid with one of the broadest host ranges of any aphid species, feeding on both dicots and monocots. It is a phloem-feeding hemipteran that causes direct feeding damage including stunted growth, leaf discoloration, and deformation, and serves as a vector for plant viruses. The species exhibits temperature-dependent development and reproduction, with optimal performance between 12.5–20°C and survival possible from 5–27.5°C. Both winged and wingless morphs occur, with parthenogenesis used for colony maintenance in laboratory settings.
Barynotus
Barynotus is a genus of broad-nosed weevils (Curculionidae: Entiminae) comprising 25 species distributed primarily in the Palaearctic region. These are relatively large weevils with predominantly nocturnal activity patterns. The genus exhibits diverse reproductive strategies, with some species being amphigonic and others parthenogenetic.
Bdelloidea
Bdelloid rotifers, bdelloids
Bdelloidea is a class of microscopic rotifers found in freshwater habitats worldwide, comprising over 450 described species. These organisms are distinguished by obligate parthenogenetic reproduction—no males have ever been observed—and their remarkable ability to survive extreme desiccation through anhydrobiosis. They range from 150–700 μm in length and can remain dormant for years, with documented cases of revival after 24,000 years frozen in Siberian permafrost. Bdelloids have been called 'ancient asexuals' due to their estimated 25+ million year history of asexual reproduction supported by fossil evidence.
Bosmina
water flea
Bosmina is a genus of small cladoceran crustaceans commonly known as water fleas. Members are distinguished from the related genus Bosminopsis by having antennae that are separated at their bases rather than fused. Bosmina species are filter feeders that consume algae and protozoans approximately 1–3 μm in size, using a dual feeding mechanism involving mesh-like setules on the second and third legs for filtering while the first leg grasps particles. The genus exhibits notable morphological plasticity, particularly in posterior mucrones and anterior antennules, which vary in response to predation pressure. Some Bosmina species have become invasive outside their native ranges, posing threats to aquatic ecosystems.
Brachycaudus helichrysi
leaf curl plum aphid, leaf-curling plum aphid, peach leaf curl aphid
Brachycaudus helichrysi is a small aphid species first described by Kaltenbach in 1843. Molecular studies have revealed it comprises two cryptic sibling lineages, B. helichrysi H1 and H2, which are morphologically indistinguishable but genetically divergent and differ in life cycle strategies. H1 follows a typical heteroecious cycle with sexual reproduction on plum trees, while H2 consists largely of obligate asexual superclones with some sexual populations on peach trees in India.