Oak-gall
Guides
Dryocosmus dubiosus
Two-horned Gall Wasp
Dryocosmus dubiosus is a cynipid gall wasp endemic to California, North America. It is an abundant species that induces distinctive galls on oak trees, specifically on leaves and catkins of coast live oaks and interior live oaks. The species is notable for the horn-like projections on its galls, which give rise to its common name.
Dryocosmus favus
Dryocosmus favus is a species of gall wasp in the family Cynipidae, first described by Beutenmueller in 1911. Members of the genus Dryocosmus are known to induce galls on oak trees (Quercus spp.). The species has been documented through a limited number of observations.
Dryocosmus floridensis
A cynipid gall wasp native to Florida that induces galls on oaks. First described by Beutenmüller in 1917, this species belongs to a genus known for causing spherical or irregular galls on oak twigs and leaves. The species name reflects its geographic association with Florida.
Dryocosmus minusculus
Pumpkin Gall Wasp
Dryocosmus minusculus is an abundant cynipid wasp endemic to California. The species induces small, round galls on oak leaves, commonly called pumpkin galls. Adults emerge in spring after overwintering as larvae within galls. The species is strictly associated with three oak species in the region.
Dryocosmus quercuslaurifoliae
Dryocosmus quercuslaurifoliae is a species of gall wasp in the family Cynipidae. Species in this genus are associated with oak trees (Quercus), inducing the formation of galls on various plant tissues. The specific epithet "quercuslaurifoliae" indicates an association with Quercus laurifolia, the laurel oak.
Dryocosmus quercuspalustris
Succulent Oak Gall Wasp
Dryocosmus quercuspalustris, commonly known as the Succulent Oak Gall Wasp, is a species of gall wasp in the family Cynipidae. The species was described by Osten Sacken in 1861. It induces galls on oak trees, with the specific epithet referencing Quercus palustris (pin oak) as a host. The species has been recorded from eastern North America including Canada and the northeastern United States.
Euvira
Euvira is a genus of rove beetles (Staphylinidae: Aleocharinae) established by Sharp in 1883. The genus was first recorded in Canada with the description of E. micmac from Nova Scotia, where specimens were found inhabiting red oak galls. At least one additional species, E. quadriceps (Casey), is known in the genus.
Feron
oak gall wasps
Feron is a genus of oak gall wasps in the family Cynipidae, established by Alfred Kinsey in 1937 and re-established in 2023. These wasps induce galls on oak trees (Quercus species) and are primarily distributed in the Nearctic region. The genus has undergone taxonomic revision, with some species previously placed in Feron now classified under Andricus. Members of this genus are part of the diverse community of gall-forming insects associated with oaks.
Feron amphorus
Feron amphorus is a species of gall wasp in the family Cynipidae, described by Weld in 1926. Like other members of this genus, it induces the formation of galls on oak species (Quercus). The species is part of a diverse radiation of cynipid wasps associated with North American oaks.
Feron atrimentum
Striped Volcano Gall Wasp
Feron atrimentum is a cynipid gall wasp that induces distinctive galls on blue oak (Quercus douglasii) leaves. The species exhibits cyclical parthenogenesis with alternating sexual and parthenogenic generations, each producing morphologically distinct gall types. The common name refers to the volcano-shaped galls with red stripes produced by the parthenogenic generation.
Feron bakkeri
Pinched Leaf Gall Wasp
Feron bakkeri is a gall wasp in the family Cynipidae that induces distinctive pink leaf galls on oaks. The species was formerly classified under the genus Andricus and has been reclassified to Feron based on phylogenetic studies. It is considered relatively uncommon compared to other oak gall wasps in its range.
Feron crystallinum
Crystalline Gall Wasp
Feron crystallinum is a cynipid gall wasp that induces distinct galls on oak species in California. The species exhibits complex alternation of generations, producing different gall morphologies and wasp forms across seasonal cycles. The parthenogenic generation forms large, pink, hairy galls on leaf undersides, while the bisexual generation produces smaller, less hairy galls. Formerly classified as Andricus crystallinus, this species has been reclassified to the genus Feron based on phylogenetic relationships.
Feron gigas
Saucer Gall Wasp
Feron gigas, the saucer gall wasp, is a cynipid wasp that induces distinct galls on oak leaves. It exhibits an alternating generation life cycle with morphologically different galls produced by all-female (agamic) and bisexual generations. The species is associated with several oak species in western North America and has been widely documented through citizen science observations.
Feron izabellae
Pink Bow-Tie Gall Wasp
Feron izabellae is an oak gall wasp described in 2023 from Northern California. The species induces distinctive pink spangle galls on white oak leaves, with galls folding at maturity to resemble bow-ties. Only the asexual generation is known. The species was named in memory of the senior author's mother and granddaughter.
Feron kingi
Red Cone Gall Wasp
Feron kingi is a gall wasp in the family Cynipidae that induces distinctive red, cone-shaped galls on white oak species (Quercus sect. Quercus). The detachable galls, approximately 5 mm tall, house parthenogenetic females and typically form in clusters on both leaf surfaces. Adults emerge from the tip of the cone in winter, an unusual seasonal pattern among cynipid wasps. The species was originally described as Andricus kingi by Bassett in 1900 before transfer to Feron.
Feron parmula
Disc Gall Wasp
Feron parmula, the disc gall wasp, is a cynipid wasp that induces distinctive disc-shaped galls on oak species, particularly white oaks and their hybrids. The galls are small, pale structures with red streaking, reaching up to 3 mm in diameter. Adult females emerge in April. The species has been documented on the Pacific coast of North America.
Feron pattersonae
Plate Gall Wasp
Feron pattersonae, the plate gall wasp, is a cynipid wasp that induces distinct galls on white oaks, particularly blue oak (Quercus douglasii). The species exhibits cyclical parthenogenesis with two alternating generations per year: an all-female parthenogenetic generation and a bisexual generation. Each generation produces morphologically different galls—flat, circular, plate-like galls in summer, and pointed capsule galls on hair-like stems later in the year. The bisexual generation's galls were originally described as a separate species, Andricus pedicellatus, by Alfred Kinsey in 1922.
Feron stellare
Sunburst Gall Wasp
Feron stellare is a cynipid gall wasp that induces distinctive galls on oak trees (Quercus species). The species was originally described as Andricus stellaris by Weld in 1926 before being transferred to the genus Feron. It is known for producing sunburst-patterned galls that serve as both shelter and food source for developing larvae. The wasp exhibits the typical complex life cycle of many Cynipidae, often involving alternating sexual and asexual generations on different oak hosts or plant parts.
Heteroecus lyoni
Lyon's Gall Wasp
Heteroecus lyoni is a gall wasp in the family Cynipidae. Species in this genus are known to induce galls on oaks (Quercus), though specific details for H. lyoni are limited in available literature. The species was named in honor of someone with the surname Lyon, a common practice in taxonomic nomenclature. Like other cynipids, it likely exhibits a complex life cycle with alternating generations between sexual and parthenogenetic forms, though this has not been explicitly documented for this species.
Heteroecus pacificus
beaked spindle gall wasp
Heteroecus pacificus, commonly known as the beaked spindle gall wasp, is a species of cynipid gall wasp native to western North America. It induces distinctive galls on canyon live oak (Quercus chrysolepis) and huckleberry oak (Quercus vaccinifolia). The species exhibits a complex life cycle with two annual generations: one sexual generation producing males and females, and one parthenogenetic generation consisting solely of females.
Heteroecus sanctaeclarae
Mushroom Gall Wasp, Steeple Gall Wasp
Heteroecus sanctaeclarae is a cynipid gall wasp that induces distinctive bud galls on oaks. The galls are bilobed, with the larval chamber located at the seam between the two sections. This species was first described by David T. Fullaway in 1911 under the name Callirhytis sanctae-clarae. It is primarily known from the Pacific coast of North America.
Holocynips badia
Holocynips badia is a species of gall wasp in the family Cynipidae, originally described by Bassett in 1900. It belongs to a genus of cynipid wasps that induce galls on oak plants. Like other members of Cynipidae, it is likely associated with oak hosts (Quercus spp.), though specific host records for this species are not well documented in available sources. The species is known from limited observations, with 15 records on iNaturalist suggesting it is rarely encountered or underreported.
Kokkocynips coxii
Kokkocynips coxii is a Nearctic gall wasp species originally described as Cynips coxii by Bassett in 1881 and later transferred from Dryocosmus to Kokkocynips in 2021 based on morphological and molecular phylogenetic evidence. It is one of six Nearctic species reclassified into Kokkocynips, expanding a genus previously considered monotypic and restricted to Mexico. The species induces galls on red oaks.
Kokkocynips difficilis
Kokkocynips difficilis is a species of gall wasp in the family Cynipidae, originally described by Ashmead in 1887 as Andricus difficilis. It belongs to the tribe Cynipini, which comprises gall-inducing wasps associated with oaks (Quercus spp.). The genus Kokkocynips was established relatively recently (2021) following taxonomic revision of the oak gall wasps. Like other members of this genus, K. difficilis likely induces galls on oak species, though specific host associations and gall morphology remain poorly documented in the available literature.
Kokkocynips imbricariae
Banded Bullet Gall Wasp
Kokkocynips imbricariae is a gall wasp species in the tribe Cynipini, transferred from Dryocosmus to Kokkocynips in 2021 based on molecular and morphological evidence. It induces galls on red oaks (Quercus section Lobatae) and is distributed in the Nearctic region. The species was originally described by Ashmead in 1896.
Loxaulus
Loxaulus is a genus of gall wasps in the family Cynipidae, tribe Cynipini. Members are small, specialized insects that induce the formation of plant galls on host plants. The genus was established by Mayr in 1881. As with other cynipine gall wasps, species likely exhibit complex life cycles involving alternating sexual and asexual generations on different host plants, though detailed studies remain limited.
Macrodiplosis
Macrodiplosis is a genus of gall midges (Cecidomyiidae) comprising approximately 19 described species. Species in this genus induce galls primarily on oak (Quercus) leaves. The genus has a Holarctic distribution with records from Europe, Asia, and North America.
Macrodiplosis qoruca
Oak Vein Pocket Gall Midge
Macrodiplosis qoruca is a gall midge in the family Cecidomyiidae, known for inducing pocket-like galls on oak leaf veins. The species is widely distributed in North America and has been documented through over 1,300 observations. Adults are small, delicate flies typical of the family. The specific epithet 'qoruca' derives from the Cherokee word for oak.
Melikaiella flora
Live Oak Petiole Gall Wasp
Melikaiella flora is a cynipid gall wasp that induces distinctive leaf galls on live oak trees (Quercus agrifolia, Q. wislizeni, and Q. chrysolepis) in California. The species exhibits a complex life cycle involving two generations, with second-generation females ovipositing into acorns rather than leaf tissue. The galls typically engulf the entire petiole and may extend into the leaf blade, representing one of the more dramatic gall morphologies among North American Cynipidae. Formerly classified as Callirhytis milleri, the species was reclassified to reflect improved understanding of cynipid phylogeny.
Melikaiella fructuosa
Melikaiella fructuosa is a species of gall wasp in the family Cynipidae, a group known for inducing plant galls. The genus Melikaiella was established relatively recently and contains species associated with oak galls. This species has been documented through a small number of observations, suggesting it may be uncommon or underreported. As with other cynipids, its biology is intimately tied to specific host plants.
Melikaiella ostensackeni
Melikaiella ostensackeni is a species of oak gallwasp described in 2014 from the United States. It belongs to the genus Melikaiella, established to accommodate species previously placed in Callirhytis and Cynips. As a cynipid wasp, it induces gall formation on oak hosts. The species is one of twelve currently recognized in the genus.
Melikaiella tumifica
Melikaiella tumifica is a cynipid gall wasp native to eastern North America. The species induces galls on oaks and exhibits a complex life cycle with alternating sexual and asexual generations. It has been introduced to Europe, where it was first documented in Germany on introduced red oak. Molecular studies have confirmed the connection between sexual and asexual generations through DNA sequencing.
Neuroterus alexandrae
Neuroterus alexandrae is a species of gall wasp in the family Cynipidae, described by Nicholls and Melika in 2021. As a member of the genus Neuroterus, it induces distinctive galls on oak leaves. The genus Neuroterus is known for producing some of the most recognizable oak galls, including spangle galls and jumping galls.
Neuroterus aliceae
Neuroterus aliceae is a species of gall wasp in the family Cynipidae, described in 2021. Like other members of the genus Neuroterus, this species induces gall formation on oak leaves. The genus Neuroterus is known for creating distinctive leaf galls, including the jumping oak galls where larval movement can cause detached galls to move. This species is part of the diverse radiation of oak-associated cynipid wasps, with over 800 species of oak gall wasps documented in North America.
Neuroterus anthracinus
Oyster Gall Wasp
Neuroterus anthracinus is a gall wasp in the family Cynipidae that forms chemically induced leaf galls on oak trees. The species exhibits heterogony, alternating between sexual and agamic (parthenogenetic) generations that produce two distinct gall types: the oyster gall and the April-bud gall. This wasp has been widely distributed across Europe and has been introduced to North America.
Neuroterus fragilis
succulent gall wasp
Neuroterus fragilis, commonly known as the succulent gall wasp, is a species of oak gall wasp in the family Cynipidae. It induces distinctive galls on California oak species, with only the spring bisexual generation currently documented. The species is notable for its relatively large galls compared to its tiny adult body size.
Neuroterus lamellae
Neuroterus lamellae is a species of gall wasp in the family Cynipidae, a group renowned for inducing distinctive growths on oak plants. As a member of the genus Neuroterus, this species participates in the complex life cycles typical of cynipid wasps, often involving alternating generations between sexual and asexual forms on different oak tissues. The specific epithet "lamellae" suggests a structural feature, possibly referring to lamellate or plate-like elements of the gall or wasp morphology. Like other Neuroterus species, it is intimately associated with oak hosts (Quercus spp.) and contributes to the remarkable diversity of gall-forming insects in North America.
Neuroterus minutus
Neuroterus minutus is a species of gall wasp in the family Cynipidae. Members of this genus are known to induce galls on oak trees (Quercus species). The species has been documented through citizen science observations, with records available on platforms such as iNaturalist. As with many cynipid wasps, detailed biological studies of this particular species appear limited in the available literature.
Neuroterus niger
jumping gall wasp, black jumping gall wasp
Neuroterus niger is a species of gall wasp in the family Cynipidae that induces distinctive galls on oak leaves. This species exhibits an alternating sexual and asexual life cycle, with different generations producing different gall types. The asexual generation creates small, spherical galls that detach from leaves and fall to the ground, where the larva's movements cause the gall to jump—giving rise to the common name "jumping gall." The sexual generation produces inconspicuous leaf galls. The species has been documented across much of eastern and central North America.
Neuroterus quercusbatatus
Oak potato gall, Potato gall wasp
Neuroterus quercusbatatus is a cynipid gall wasp that induces distinctive potato-shaped galls on oak leaves. The species exhibits a complex life cycle involving alternating generations between leaf galls and other oak tissues. As a member of the diverse Neuroterus genus, it contributes to the remarkable gall-forming diversity associated with North American oaks. The species has been documented through hundreds of observations, indicating it is relatively common and widespread in suitable habitat.
Neuroterus quercusmajalis
Neuroterus quercusmajalis is a species of gall wasp in the family Cynipidae that induces galls on oak leaves. As a member of the genus Neuroterus, it is part of a diverse group of cynipid wasps specialized on oaks. The species was described by Beutenmüller in 1909. Like other Neuroterus species, it exhibits complex life cycles involving both sexual and asexual generations that produce different gall types on oak tissues.
Neuroterus quercusminutissimus
Neuroterus quercusminutissimus is a species of cynipid gall wasp in the genus Neuroterus. The species was described by Ashmead in 1885 and is associated with oak trees (Quercus species), as indicated by its specific epithet. Like other Neuroterus species, it induces the formation of galls on oak tissue. The genus Neuroterus contains approximately 50-60 species, many of which are known for their complex life cycles involving alternating generations that produce different gall types on oak leaves or other plant parts.
Neuroterus quercusverrucarum
oak flake gall wasp
Neuroterus quercusverrucarum is a species of gall wasp in the family Cynipidae that induces distinctive galls on oak leaves. First described by Osten Sacken in 1861, this species is part of the diverse Neuroterus genus, which includes many oak-associated gall wasps with complex life cycles often involving alternating sexual and asexual generations. The species creates characteristic leaf galls that serve as both food source and protective nursery for developing larvae. Like other cynipid wasps, N. quercusverrucarum exhibits intricate ecological relationships with its oak hosts and associated parasitoid communities.
Neuroterus rileyi
Neuroterus rileyi is a species of cynipid gall wasp in the family Cynipidae, genus Neuroterus. Like other Neuroterus species, it induces characteristic galls on oak (Quercus) hosts. The genus Neuroterus is known for producing small, often disc-shaped or spangle galls on oak leaves, with some species exhibiting complex life cycles involving alternate generations on different oak tissues. Specific details about N. rileyi's gall morphology and biology remain limited in available sources.
Neuroterus saltatorius
Jumping Gall Wasp
Neuroterus saltatorius, commonly known as the jumping gall wasp, is a North American oak gall wasp in the family Cynipidae. The species is notable for producing small, round galls that detach from leaves and exhibit a distinctive jumping behavior caused by larval movements. It has a complex life cycle with alternating bisexual and parthenogenetic generations, each producing different gall types on oak hosts.
Neuroterus tantulus
Neuroterus tantulus is a species of gall wasp in the family Cynipidae. Like other members of the genus Neuroterus, this species induces the formation of galls on oak leaves. The genus Neuroterus is known for producing small, often disc-shaped or pouch-like leaf galls on various oak species. Neuroterus tantulus has been documented through numerous observations, indicating it is relatively widespread where its oak hosts occur.
Neuroterus washingtonensis
Neuroterus washingtonensis is a North American cynipid gall wasp first described by Beutenmüller in 1913. It is known to induce galls on oak (Quercus) species and has been documented as a host for the introduced parasitoid wasp Bootanomyia dorsalis on the Pacific coast of North America. The species is part of the diverse Neuroterus genus, which includes gall-forming wasps known for complex life cycles often involving alternating generations on different oak tissues.
Odontocynips nebulosa
root gall wasp
Odontocynips nebulosa is a cynipid wasp that induces large, woody, subterranean galls on oak roots. Adults are small and rarely observed; the galls are the primary sign of its presence. The species was long misidentified due to confusion with a different gall-former on oak leaves. It has a two-year life cycle and is restricted to the southeastern and central United States.
Ormyridae
Ormyridae is a small family of parasitic wasps in the superfamily Chalcidoidea. Members are parasitoids or hyperparasitoids of gall-forming insects, primarily cynipid wasps and tephritid flies. The family comprises approximately 153 species across three subfamilies (Asparagobiinae, Hemadinae, Ormyrinae) and several genera, with the majority in the genus Ormyrus. Ormyridae has a cosmopolitan distribution but is almost entirely absent from South America. Adults of many species exhibit iridescent coloration and distinctive metasomal sculpturing.
Ormyrus
Ormyrus is a genus of small chalcid wasps in the family Ormyridae, containing approximately 145 described species. These wasps are parasitoids primarily associated with gall-forming insects, including cynipid gall wasps, chalcid wasps, gall midges, and tephritid fruit flies. The genus exhibits significant cryptic diversity, as demonstrated by the case of Ormyrus labotus, long considered a single generalist species attacking over 65 host species, but now recognized as a complex of at least 16–18 genetically distinct, morphologically identical specialist species. Ormyrus species are found across the Old World and North America.