Parthenogenesis
Guides
Trichadenotecnum
booklice, barklice
Trichadenotecnum is a large genus of barklice in the family Psocidae, containing over 200 described species. It is distinguished from related genera by forming a monophyletic group with highly variable genital morphology, particularly in males. The genus exhibits diverse reproductive strategies, including both biparental sexual reproduction and obligate or facultative parthenogenesis (thelytoky) depending on the species.
Trichadenotecnum castum
common barklouse
Trichadenotecnum castum is a uniparental barklouse species in the family Psocidae, described by Betz in 1983. It is one of three obligately parthenogenetic species derived from the biparental ancestor T. alexanderae. Populations are composed exclusively of females that reproduce via obligate thelytokous parthenogenesis. The species belongs to the T. alexanderae species complex, a group of closely related barklice distinguished primarily by reproductive mode and subtle morphological differences.
Trichadenotecnum merum
common barklouse
Trichadenotecnum merum is a uniparental barklouse species described in 1983 as part of the Trichadenotecnum alexanderae species complex. It reproduces exclusively through obligatory parthenogenesis (thelytoky), with populations composed entirely of females. The species was established through mating tests, life history observations, and morphological analysis across the geographic range of the species complex. As a member of the family Psocidae, it belongs to a group commonly known as common barklice.
Trichogramma
Trichogramma wasps, egg parasitoid wasps
Trichogramma is a genus of minute polyphagous wasps that are endoparasitoids of insect eggs. With over 200 species worldwide, it is one of approximately 80 genera in the family Trichogrammatidae. These wasps are among the most extensively studied and widely used biological control agents globally, with more than a thousand published papers on their biology and applications. Trichogramma species have also gained attention in neuroscience research due to their extremely small brain size—fewer than 10,000 neurons—while still exhibiting complex behaviors.
biological-controlegg-parasitoidintegrated-pest-managementneuroscience-modelWolbachiamass-rearingagricultural-pest-managementChalcidoideaTrichogrammatidaeaugmentative-biological-controlinundative-releasesustainable-agriculturerice-pest-managementcotton-pest-managementorchard-pest-managementforest-pest-managementparthenogenesischemosensory-biologyminiaturizationbrain-evolutionTrichoniscus
pygmy woodlice
Trichoniscus is a genus of small terrestrial isopods (woodlice) containing over 100 species. The genus is notable for including species with both sexual and parthenogenetic reproductive modes, most prominently exemplified by Trichoniscus pusillus, which exists as diploid sexual and triploid asexual forms. These isopods are among the smallest woodlice, typically only a few millimeters in length, and are significant study organisms for research on the evolutionary maintenance of sexual reproduction.
Triops longicaudatus
Longtail Tadpole Shrimp, American Tadpole Shrimp, Rice Tadpole Shrimp
Triops longicaudatus is a freshwater branchiopod crustacean commonly known as the longtail tadpole shrimp or rice tadpole shrimp. It inhabits ephemeral ponds and pools across western North America, South America, Japan, South Korea, and Pacific Islands. The species is notable for its ancient lineage—morphologically unchanged for over 170 million years—and its remarkable desiccation-resistant eggs that can survive decades in dry sediment before hatching upon rehydration. It displays multiple reproductive strategies including parthenogenesis, hermaphroditism, and sexual reproduction. In California agriculture, it is a significant early-season pest of rice, damaging germinating seeds in flooded fields.
Tuberolachnus
giant willow aphid, giant bark aphid
Tuberolachnus is a genus of aphids in the family Aphididae, established by Mordvilko in 1909. The genus contains three described species, with Tuberolachnus salignus (the giant willow aphid) being the most well-known and widely studied. Members of this genus are among the largest aphids in the world, with body lengths reaching up to 5.8 mm. They are notable for their obligate parthenogenetic reproduction, extremely low genetic diversity, and status as invasive pests in multiple regions including New Zealand, India, and Patagonia.
Tuberolachnus salignus
Giant Willow Aphid
Tuberolachnus salignus, the giant willow aphid, is one of the largest aphid species in the world, reaching up to 5.8 mm in body length. It is an obligate parthenogenetic species, reproducing without males and producing genetically identical female offspring. Native to Asia, it has become cosmopolitan, spreading to all continents except Antarctica. The species feeds primarily on willow phloem sap and is considered an invasive pest in regions including New Zealand, where it impacts willow-based industries and apiculture through copious honeydew production.
Underwoodia iuloides
Underwoodia iuloides is a millipede species in the family Caseyidae. It is one of three species in the genus Underwoodia, which exhibits a Holarctic distribution pattern. The species is characterized by specific configurations of the anterior gonopod colpocoxites, particularly branches a and c. Populations show a strongly female-biased sex ratio, suggesting parthenogenesis.
Uroleucon ambrosiae
Brown Ambrosia Aphid
Uroleucon ambrosiae is a medium-sized aphid in the family Aphididae, commonly known as the brown ambrosia aphid. Native to North America, it exhibits geographic variation in host specificity, with eastern populations highly specialized on giant ragweed (Ambrosia trifida) while southwestern populations feed more broadly on Asteraceae plants. In Brazil, it has emerged as a significant pest of hydroponically-grown lettuce, where it vectors lettuce mosaic virus and promotes sooty mold through honeydew excretion. The species reproduces parthenogenetically during spring and summer, forming all-female colonies. Its populations serve as important prey for diverse natural enemies including flower fly larvae, lady beetles, lacewings, and parasitic wasps, making it a key component of biological control food webs in both natural and agricultural systems.
Uroleucon caligatum
Northern Green Goldenrod Aphid
Uroleucon caligatum is a North American aphid species in the family Aphididae, specialized on goldenrod hosts in the genus Solidago. The species exhibits significant intraspecific variability in performance across different host plant clones. Like other Uroleucon species, it likely reproduces parthenogenetically during the growing season. Field studies have demonstrated that plant clone identity strongly affects aphid developmental time, adult weight, and colony growth.
Uroleucon cirsii
Large Thistle Aphid
Uroleucon cirsii, commonly known as the large thistle aphid, is a species of aphid in the family Aphididae. It is a phloem-feeding insect that specializes on thistles and related plants in the Asteraceae family. Like other members of the genus Uroleucon, it exhibits parthenogenetic reproduction during the growing season, forming colonies of females that reproduce without males. The species is known from Europe, with confirmed records in Belgium, Denmark, and Norway.
Uroleucon erigeronense
Large fleabane daisy aphid
Uroleucon erigeronense is a species of aphid in the family Aphididae, first described by Thomas in 1878. It feeds primarily on plants in the Asteraceae family, with a particular association with Erigeron (fleabane) species. The species exhibits flexible reproductive strategies: holocyclic in northern climates, producing sexual forms in autumn, and anholocyclic in warmer regions. It shows seasonal host-shifting behavior, moving between overwintering perennial hosts and blooming annuals. Native to North America, it has been introduced to Europe, Australia, and Korea.
Uroleucon eupatoricolens
Uroleucon eupatoricolens is an aphid species in the family Aphididae. Like other members of the genus Uroleucon, it is a sap-sucking insect that feeds on plants in the Asteraceae family. The species reproduces parthenogenetically during spring and summer, producing all-female colonies. When disturbed, colonies exhibit synchronized twitching and kicking defensive behaviors. These aphids serve as important prey for diverse predator communities including lady beetles, lacewings, flower flies, and spiders.
Uroleucon nigrotuberculatum
red goldenrod aphid
Uroleucon nigrotuberculatum, commonly known as the red goldenrod aphid, is a North American aphid species introduced to Japan. In its native range, it is a specialist feeder on Solidago (goldenrod) species. Following introduction to Japan, this aphid has demonstrated remarkable dietary flexibility, expanding its host range to include multiple exotic plant species beyond its native specialization. The species exhibits complex ecological interactions, including semiochemical-mediated relationships with gall-forming flies and serves as prey for various native parasitoids and predators in its introduced range.
Uroleucon obscuricaudatum
Dusky-tailed Sunflower Aphid
Uroleucon obscuricaudatum is a North American aphid species in the family Aphididae, commonly known as the Dusky-tailed Sunflower Aphid. It is a specialist feeder on Heliopsis helianthoides (oxeye sunflower) and related Asteraceae plants. The species exhibits typical aphid life history traits including parthenogenetic reproduction during the growing season. Like other Uroleucon species, it produces honeydew and serves as prey for diverse natural enemies including lady beetles, flower flies, lacewings, and spiders.
Uroleucon pseudambrosiae
Wild Lettuce Aphid
Uroleucon pseudambrosiae is a North American aphid species that feeds on wild lettuce (Lactuca spp.) and related Asteraceae plants including dandelion (Taraxacum), pilewort (Erechtites hieracifolia), and Sonchus asper. It is known to serve as a vector for watermelon mosaic virus. The species exhibits parthenogenetic reproduction during spring and summer, forming all-female colonies.
Uroleucon rudbeckiae
goldenglow aphid
Uroleucon rudbeckiae, the goldenglow aphid, is a bright red aphid species specialized on Rudbeckia host plants. Adults measure 2.4–3.2 mm with distinctive yellow legs, black antennae, and reticulated siphunculi. Populations exhibit characteristic mid-summer rise and late-summer decline on native perennials, with colony dynamics driven by immigration patterns and predation pressure rather than weather or host quality degradation.
Uroleucon sonchi
Sow-thistle Aphid, Large Sow-thistle Aphid, Brown Lettuce Aphid
Uroleucon sonchi is a large aphid species in the family Aphididae, commonly known as the sow-thistle aphid or brown lettuce aphid. Native to the Palaearctic region, it has been introduced to multiple continents and is now cosmopolitan in distribution. The species is economically significant as a pest of cultivated lettuce and related crops, while also occurring on wild Asteraceae hosts. It reproduces parthenogenetically during spring and summer, typical of many aphids.
Uroleucon taraxaci
Bronze-brown Dandelion Aphid
Uroleucon taraxaci is a species of aphid in the family Aphididae, commonly known as the Bronze-brown Dandelion Aphid. As a member of the genus Uroleucon, it shares characteristics with related species that exhibit parthenogenetic reproduction during spring and summer, forming all-female colonies. The species is associated with plants in the Asteraceae family, particularly dandelion (Taraxacum). Like other Uroleucon aphids, it produces honeydew that attracts predators and parasitoids. The species has been documented across parts of Europe and Asia.
Uroleucon tuataiae
Uroleucon tuataiae is a species of aphid in the family Aphididae, first described by Olive in 1963. It belongs to the large genus Uroleucon, which contains numerous species associated with plants in the Asteraceae family. Like other members of this genus, it is presumed to be a phloem-feeding insect that reproduces parthenogenetically during favorable seasons. The species is recognized as valid in major taxonomic databases including GBIF and the Catalogue of Life.
Uroleucon verbesinae
Bicolored Frostweed Aphid
Uroleucon verbesinae is a North American aphid species in the family Aphididae. It belongs to the large genus Uroleucon, whose members typically feed on plants in the Asteraceae family. The species reproduces parthenogenetically during spring and summer, producing all-female colonies. Like other Uroleucon aphids, it exhibits synchronized defensive behaviors when disturbed.
Uropodina
Uropodina is an infraorder of mites in the order Mesostigmata, characterized by morphologically variable forms with fused sternal and ventral shields, short legs with reduced setae, and stigmata positioned between the second and third leg pairs. Most species inhabit soil, forest litter, and decaying organic matter, where they function primarily as predators of small invertebrates. Many species exhibit phoresy during the deutonymph stage, attaching to insects and other arthropods for dispersal using a secreted elastic pedicel. Reproduction is predominantly sexual, though parthenogenesis occurs in some species with males rare or absent.
Valenzuela flavidus
yellow barklouse
Valenzuela flavidus is a barklouse species in the family Caeciliusidae, originally described as Psocus flavidus by Stephens in 1836 and later transferred to Valenzuela by Navás in 1924. The species exhibits complex population structure with both sexual and asexual reproduction modes: European populations are all-female and triploid, reproducing via parthenogenesis, while North American populations contain males and appear to be diploid with sexual reproduction. This cryptic diversity within the species complex has been confirmed through genomic studies.
Venturia canescens
Venturia canescens is a solitary koinobiont endoparasitoid wasp in the family Ichneumonidae. The species exhibits both sexual and asexual (parthenogenetic) populations, with the asexual strain being highly synovigenic—continuing egg maturation throughout adult life. Females inject virus-like particles (VLPs) derived from an integrated nudivirus into host larvae during oviposition; these VLPs suppress the host immune system and prevent encapsulation of the parasitoid egg. The species is a significant biological control agent of stored-product pests, particularly pyralid moth larvae.
Xyleborus bispinatus
Xyleborus bispinatus is a tropical ambrosia beetle in the tribe Xyleborini. Native to the Americas, it has established populations in Florida and been introduced to the Iberian Peninsula. The beetle maintains nutritional mutualisms with ambrosia fungi and has demonstrated unusual flexibility in acquiring symbionts from invasive beetle species, including plant pathogens. It is a potential vector for laurel wilt disease and has been associated with avocado decline in multiple regions.
Xyleborus glabratus
Redbay Ambrosia Beetle
Xyleborus glabratus is a small ambrosia beetle native to Asia that has become a destructive invasive pest in the southeastern United States since its detection in 2002. The species is the primary vector of Raffaelea lauricola, the fungal pathogen that causes laurel wilt disease, which has killed millions of native Lauraceae trees including redbay, sassafras, and avocado. Females are the dispersing sex and initiate galleries in host wood, where they cultivate fungal gardens as food for their offspring. The beetle's rapid spread threatens both forest ecosystems and commercial avocado production.