Gall-wasp
Guides
Callirhytis
Callirhytis is a genus of gall wasps comprising more than 90 described species, all members of the family Cynipidae. These wasps are specialized herbivores that induce the formation of galls on oak trees (Quercus spp.) in North America. The genus exhibits complex life cycles with alternating sexual and asexual generations, often producing morphologically distinct galls. Callirhytis species are among the most extensively studied cynipids due to their ecological importance and the structural diversity of their galls.
Callirhytis balanacea
Callirhytis balanacea is a species of cynipid wasp in the family Cynipidae, known for inducing pea-sized galls on oak trees. The species produces distinctive pip galls on oak hosts, which exude sugary secretions that serve as food sources for other insects. It has been documented as a gall-forming insect with specific ecological interactions, including serving as a food source for hairstreak butterflies that feed on gall exudates rather than nectar.
Callirhytis balanopsis
Callirhytis balanopsis is a species of gall wasp in the family Cynipidae. The species induces galls on oak hosts, continuing the genus's well-documented association with Quercus species. Like other Callirhytis species, it exhibits a complex life cycle with alternating sexual and asexual generations that produce distinct gall types. The specific epithet 'balanopsis' references the acorn-like appearance of its galls.
Callirhytis carmelensis
Mottled Acorn Gall Wasp
A cynipid gall wasp endemic to California that induces distinctive galls on acorns of coast live oak (Quercus agrifolia) and interior live oak (Quercus wislizeni). The galls form at the acorn attachment point, often preventing normal nut development. The species produces a honeydew secretion that attracts other insects. Despite being described in 1922, it remains uncommon and poorly studied relative to other California oak gall wasps.
Callirhytis clavula
Callirhytis clavula is a species of gall wasp in the family Cynipidae, known to induce galls on oak trees (Quercus). Like other members of the genus Callirhytis, it exhibits a complex life cycle involving alternating generations that produce different gall types on different plant tissues. The species is native to eastern North America, with records from Canada and the United States. Specific details of its gall morphology and biology remain poorly documented in the primary literature.
Callirhytis congregata
sausage flower gall wasp
Callirhytis congregata is a cynipid gall wasp native to California that induces distinctive galls on the catkins of three oak species: coast live oak (Quercus agrifolia), interior live oak (Quercus wislizeni), and canyon live oak (Quercus chrysolepis). The species was originally described by William Harris Ashmead in 1896 under the genus Andricus. It is considered locally common within its range. The galls are described as rugose, yellowish-brown woody swellings with multiple cells, appearing to grow from the tips of slender twigs with a long peduncle-like base.
Callirhytis ellipsoida
Callirhytis ellipsoida is a species of gall wasp in the family Cynipidae. Like other members of its genus, it induces the formation of galls on oak hosts. The species exhibits the typical complex life cycle of oak cynipids, with alternating sexual and asexual generations that produce morphologically distinct galls.
Callirhytis elliptica
Callirhytis elliptica is a species of gall wasp in the family Cynipidae. The species is known to induce galls on oak hosts, consistent with the genus's well-documented association with oaks. As with other members of Callirhytis, this species exhibits the complex life cycles typical of cynipid gall wasps, often involving alternating sexual and asexual generations that produce different gall forms. Specific details regarding the morphology of its galls and precise host oak species remain limited in published sources.
Callirhytis favosa
Honeycomb leaf gall wasp
Callirhytis favosa is a gall wasp in the family Cynipidae that induces distinctive honeycomb-patterned galls on oak leaves. The species exhibits the complex life cycle typical of many cynipids, with alternating sexual and asexual generations that produce different gall types on different oak tissues. The specific epithet 'favosa' refers to the honeycomb-like appearance of the galls.
Callirhytis flavipes
Callirhytis flavipes is a species of gall wasp in the family Cynipidae. Species in this genus are known to induce galls on oak trees (Quercus spp.). The genus Callirhytis is part of the tribe Cynipini, which comprises the oak gall wasps. Specific biological details for C. flavipes remain poorly documented in accessible literature.
Callirhytis frequens
Callirhytis frequens is a species of gall wasp in the family Cynipidae. Members of the genus Callirhytis are known to induce galls on oak species (Quercus). The species exhibits the complex life cycle typical of many cynipids, with alternating sexual and asexual generations that often produce morphologically distinct galls on different oak tissues or species. As with most Callirhytis species, detailed natural history information for C. frequens remains limited in published literature.
Callirhytis furva
Callirhytis furva is a species of gall wasp in the family Cynipidae. Like other members of the genus Callirhytis, it induces galls on oak trees (Quercus spp.). The species exhibits the complex life cycle typical of many cynipid wasps, with alternating sexual and asexual generations that often produce distinct gall morphologies on different plant tissues.
Callirhytis gallaestriatae
Callirhytis gallaestriatae is a species of gall wasp in the family Cynipidae. As with other members of this genus, it induces galls on oak hosts (Quercus species). The species exhibits the complex life cycle typical of many cynipids, with alternating sexual and asexual generations that often produce morphologically distinct galls. The specific epithet "gallaestriatae" suggests association with galls bearing striations or stripes.
Callirhytis glandulus
Callirhytis glandulus is a species of gall wasp in the family Cynipidae. Like other members of the genus Callirhytis, this species induces the formation of galls on oak hosts (Quercus). The species was described by Beutenmüller in 1913. As with many Cynipidae, it likely exhibits an alternating generation life cycle with distinct sexual and asexual phases that produce different gall morphologies.
Callirhytis juvenca
Callirhytis juvenca is a species of gall wasp in the family Cynipidae. Like other members of its genus, it induces galls on oak hosts (Quercus species). The species exhibits the typical complex life cycle of cynipid gall wasps, with alternating sexual and asexual generations that often produce morphologically distinct galls. Specific details regarding its host associations and gall morphology remain limited in published literature.
Callirhytis lanata
Callirhytis lanata is a species of gall wasp in the family Cynipidae. It induces galls on oak species (Quercus), with specific host associations and gall morphology distinguishing it from congeners. The species exhibits the typical cynipid life cycle with alternating sexual and asexual generations that produce different gall forms.
Callirhytis pedunculata
Callirhytis pedunculata is a species of gall wasp in the family Cynipidae. Like other members of its genus, it induces galls on oak trees (Quercus species). The species exhibits the typical complex life cycle of cynipid gall wasps, with alternating sexual and asexual generations that often produce distinct gall morphologies on different oak tissues.
Callirhytis perdens
Ruptured Twig Gall Wasp
Callirhytis perdens is a gall wasp in the family Cynipidae that induces distinctive stem galls on several oak species in California. Unlike many gall wasps where larvae develop entirely within attached galls, this species exhibits a unique life history where mature larval capsules are expelled from fissures in the gall and complete development on the ground. The species was formerly classified under the genus Andricus. It is considered locally abundant within its restricted range.
Callirhytis perditor
Callirhytis perditor is a species of gall wasp in the family Cynipidae. Like other members of its genus, it induces the formation of galls on oak trees (Quercus species). The species exhibits the complex life cycle typical of many cynipid wasps, with alternating sexual and asexual generations that often produce morphologically distinct galls on different parts of the host plant.
Callirhytis perfoveata
leaf ball gall wasp
Callirhytis perfoveata is a cynipid gall wasp endemic to California that induces distinctive spherical leaf galls on oak trees. Formerly classified as Andricus perfoveata, this species specifically targets coast live oak (Quercus agrifolia), interior live oak (Q. wislizeni), and occasionally California black oak (Q. kelloggii). The galls form embedded within leaf tissue, appearing as roughly spherical structures that emerge bright green and mature to brown.
Callirhytis pigra
oak midrib gall
A cynipid gall wasp that induces distinctive galls on oak leaves. The species exhibits the typical complex life cycle of oak gall wasps, with alternating sexual and asexual generations that produce different gall morphologies on different oak tissues. The common name refers to the gall's position along the leaf midrib.
Callirhytis piperoides
Callirhytis piperoides is a gall wasp in the family Cynipidae. Like other members of its genus, it induces gall formation on oak hosts (Quercus species). The species was described by Bassett in 1900. As with many Cynipidae, it exhibits a complex life cycle involving alternating generations that may produce different gall types on different plant tissues.
Callirhytis pulchra
Callirhytis pulchra is a species of gall wasp in the family Cynipidae, first described by Bassett in 1890. Like other members of its genus, this species induces distinctive galls on oak trees (Quercus spp.). The species exhibits the complex life cycles typical of Cynipidae, often involving alternating sexual and asexual generations that produce different gall types on different plant tissues. As an oak specialist, it contributes to the remarkable diversity of gall-forming insects associated with this tree genus in North America.
Callirhytis quercusagrifoliae
bud gall wasp
Callirhytis quercusagrifoliae, commonly known as the bud gall wasp, is a cynipid gall wasp that induces galls specifically on the flower buds of coast live oaks (Quercus agrifolia) and interior live oaks (Quercus wislizeni). The species has been documented in California, North America. Like other cynipids, it manipulates plant tissue development through chemical secretions to create protective structures for its larvae.
Callirhytis quercusbatatoides
Southern Live Oak Stem Gall Wasp
Callirhytis quercusbatatoides is a cynipid gall wasp that induces stem galls on Southern live oak (Quercus virginiana) and related oak species. The species exhibits the complex life cycle typical of many oak gall wasps, with alternating sexual and asexual generations that produce morphologically distinct galls. The specific epithet 'quercusbatatoides' references the gall's resemblance to a sweet potato (batata). The species is well-documented in the southeastern United States where its host oaks are native.
Callirhytis quercuscornigera
Horned Oak Gall Wasp
Callirhytis quercuscornigera, the horned oak gall wasp, is a cynipid wasp that forms distinctive woody galls on oak twigs. The species exhibits complex heterogony—a cyclical parthenogenesis with alternating sexual and asexual generations that produce different gall types on different oak tissues. The horned twig galls are large, woody structures with conspicuous horn-like projections through which adult wasps emerge. Heavy infestations have been documented to contribute to decline and mortality of pin oaks, particularly in urban and suburban settings.
Callirhytis quercusfutilis
Oak Wart Gall Wasp
Callirhytis quercusfutilis is a cynipid gall wasp known for inducing distinctive wart-like galls on white oak group oaks. The species exhibits a complex life cycle with alternating generations: an asexual generation that develops in scurfy bark at the base of host tree trunks or roots, and a sexual generation that produces leaf galls. The species is restricted to central and eastern North America and is specifically associated with oaks in the Quercus section Quercus (white oaks).
Callirhytis quercusgemmaria
Callirhytis quercusgemmaria is a gall wasp in the family Cynipidae that induces galls on oak (Quercus) species. Like other members of the genus Callirhytis, this species has a complex life cycle involving alternating generations that produce different gall types on different parts of the host plant. The specific epithet 'quercusgemmaria' refers to its association with oak buds or gemmae. This species is part of the highly diverse oak gall wasp fauna of North America, where more than 1,300 cynipid species have been described, most with intimate host relationships with particular oak species.
Callirhytis quercusmodesta
Callirhytis quercusmodesta is a species of gall wasp in the family Cynipidae. The species induces galls on oaks (Quercus spp.) as part of its life cycle. Like other members of the genus Callirhytis, it exhibits heterogony, with alternating sexual and asexual generations that produce morphologically distinct galls. The species is known from the central United States.
Callirhytis quercusoperator
Woolly Catkin Gall Wasp
Callirhytis quercusoperator is a cynipid gall wasp that induces galls on oak catkins. The species exhibits a complex life cycle with alternating generations, a common trait among Cynipidae. The galls produced by this species are characterized by a woolly or fuzzy appearance on catkins of oak trees. First described by Osten Sacken in 1862, it remains an active subject of observation with over 1,000 records on iNaturalist.
Callirhytis quercuspunctata
Gouty Oak Gall Wasp
Callirhytis quercuspunctata, commonly known as the Gouty Oak Gall Wasp, is a cynipid gall wasp that induces gouty oak galls on oak trees. Like other members of the genus Callirhytis, this species has a complex life cycle involving alternating generations that produce distinct gall types on different oak tissues. The wasp manipulates oak growth through chemical secretions to create protective structures housing developing larvae. The species is associated with oaks (Quercus spp.) and has been documented across eastern North America.
Callirhytis quercussuttoni
Gouty Stem Gall Wasp
Callirhytis quercussuttoni is a gall wasp in the family Cynipidae that induces galls on stems of oaks in the red oak group (section Lobatae). The species is restricted to the west coast of North America, where it has been documented on coast live oak (Quercus agrifolia) and interior live oak (Q. wislizeni). Its common name refers to the swollen, irregular galls it produces on host stems.
Callirhytis quercusventricosa
Callirhytis quercusventricosa is a species of gall wasp in the family Cynipidae, known for inducing galls on oaks (Quercus). The species exhibits the complex life cycle typical of Cynipini, with alternating sexual and asexual generations that produce distinct gall morphologies on different oak tissues. It is one of numerous oak-galling species in the large genus Callirhytis.
Callirhytis rugulosa
Callirhytis rugulosa is a species of gall wasp in the family Cynipidae. Like other members of this family, it induces the formation of galls on host plants, though specific gall morphology and host associations for this species are not well documented in available sources. The species belongs to a genus predominantly associated with oak galls.
Callirhytis seminator
Wool Sower, Wool Sower Gall Wasp
Callirhytis seminator, commonly known as the wool sower, is a gall wasp that induces distinctive cotton-like galls on white oak trees. The species exhibits a complex alternating life cycle involving two different gall types, though the alternate gall form remains unidentified. Adults are small, dark brown wasps approximately 3 mm in length. The species poses no threat to humans or oak tree health.
Callirhytis seminosa
Callirhytis seminosa is a species of gall wasp in the family Cynipidae. Like other members of its genus, this species induces galls on oak hosts (Quercus spp.). The genus Callirhytis is known for forming distinct galls on oaks, with different species typically associated with specific oak species or gall morphologies. The specific epithet "seminosa" suggests a possible association with seed or acorn-related structures, though this remains speculative without direct observation.
Callirhytis serricornis
kernel flower gall wasp
Callirhytis serricornis is a cynipid gall wasp endemic to California that induces distinct bottle- or vase-shaped galls on oak trees. The species exhibits alternating generations with different gall phenotypes: first-generation galls are brown, while second-generation galls are red and green. It is restricted to two host oak species in the western United States.
Callirhytis tubicola
Callirhytis tubicola is a species of gall wasp in the family Cynipidae. Like other members of its genus, it induces galls on oak trees. The species exhibits the complex life cycle typical of oak gall wasps, with alternating sexual and asexual generations that produce distinct gall morphologies on different oak tissues.
Ceroptres
Ceroptres is a genus of gall wasps in the tribe Ceroptresini (Cynipidae). The genus includes 43 described species, of which 40 are known from North America. Ceroptres species are inquilines: they do not induce their own galls but instead oviposit into galls formed by other organisms. Host galls are primarily those induced by other gall wasps (Cynipini), though some species use galls formed by gall midges (Cecidomyiidae). Species are host specialists, typically associated with a single host gall species or with several phylogenetically or ecologically related galls.
Ceroptresini
Ceroptresini is a tribe of inquiline gall wasps in the family Cynipidae, containing two genera: Ceroptres (with 43 species) and Buffingtonella (with one species). First established as a tribe in 2015, these wasps are predominantly found in North America, though some species occur in the Eastern Palearctic and Oriental regions. Members of this tribe do not induce their own galls but instead inhabit galls created by other cynipid wasps, primarily on oaks (Quercus spp.), with some species reared from cecidomyiid midge galls.
Cynips
oak gall wasps
Cynips is a genus of gall wasps comprising approximately 39 species, all associated with oak trees (Quercus spp.). The genus includes the well-known common oak gall wasp (C. quercusfolii), which induces spherical galls on oak leaf undersides. Species in this genus exhibit heterogony, alternating between sexual and asexual generations that typically produce morphologically distinct galls. The genus was established by Linnaeus in 1758 and remains taxonomically stable, though some former members (such as Antron) have been reinstated as separate genera.
Cynips conspicuus
Fuzzy Gall Wasp
Cynips conspicuus, commonly known as the Fuzzy Gall Wasp, is a species of gall wasp in the family Cynipidae. The species is known for inducing galls on oak trees. It has been documented in 1,259 iNaturalist observations, indicating it is relatively well-observed among gall wasp species.
Cynips mirabilis
Speckled Gall Wasp
Cynips mirabilis, commonly known as the speckled gall wasp, is a cynipid wasp native to western North America. The species induces distinctive galls on Oregon oak (Quercus garryana) leaves, with larvae developing inside detachable, speckled galls. It exhibits a complex life cycle involving multiple generations, a common trait among Cynipidae. The species was formerly placed in the genus Besbicus but has been reclassified under Cynips. It is one of the most frequently observed gall wasps in its range, with over 2,000 documented observations.
Cynips multipunctata
Gray Midrib Gall Wasp
Cynips multipunctata is a cynipid gall wasp that induces galls on oak trees, primarily blue oak (Quercus douglasii), in western North America. The species was formerly classified under the genus Besbicus. It is most commonly encountered in California, where it produces distinctive detachable galls on leaf midribs. The galls are solid except for a central larval chamber.
Diastrophus cuscutaeformis
blackberry seed gall wasp
Diastrophus cuscutaeformis is a gall wasp in the family Cynipidae that induces seed galls on Rubus species, particularly blackberries. The species is well-documented through iNaturalist observations, with 867 records contributing to its known distribution and phenology. As a cynipid wasp, it has a complex life cycle involving alternation between sexual and asexual generations, though specific details for this species remain incompletely described in published literature.
Diastrophus kincaidii
thimbleberry gallmaker wasp, thimbleberry gall wasp
Diastrophus kincaidii is a cynipid wasp that induces integral stem galls on thimbleberry plants (Rubus parviflorus). The galls form the basis of a complex derivative ecosystem, supporting a weevil and at least nine species of parasitic wasps. Females are flightless and exhibit communal oviposition behavior, with multiple females often ovipositing at the same site. Gall shape and size influence parasitism rates, with large, round, multilocular galls showing lower parasite frequency than small or narrow galls.
Diastrophus nebulosus
Blackberry Knot Gall Wasp
Diastrophus nebulosus is a cynipid gall wasp that induces compound stem galls on Rubus flagellaris. It exhibits arrhenotoky, the first reported instance of this reproductive mode for a Nearctic species in the genus Diastrophus. The species supports a complex community of parasitoids and inquilines, with heavy infestation reducing primary host populations to near zero in some colonies over 1-2 seasons.
Diastrophus potentillae
cinquefoil bud gall wasp
Diastrophus potentillae is a gall wasp in the family Cynipidae that induces bud galls on cinquefoil plants. The species is known from eastern North America, with records from Canada and the northeastern United States. It has been documented on Potentilla canadensis and P. simplex as host plants.
Diastrophus turgidus
Diastrophus turgidus is a species of gall wasp in the family Cynipidae, first described by Bassett in 1870. It is known to induce galls on brambles (Rubus species), particularly affecting the stems or fruits of raspberry and blackberry plants. The species is recorded from multiple provinces across central and eastern Canada. Like other members of the genus Diastrophus, it has a complex life cycle involving both sexual and asexual generations, though specific details for this species remain poorly documented.
Diplolepididae
rose gall wasps
Diplolepididae is a small family of gall-inducing wasps in the order Hymenoptera, recently elevated from tribe status within Cynipidae based on genetic and morphological evidence. The family comprises two subfamilies: Diplolepidinae (~60 species in Diplolepis and Liebelia) which induce galls exclusively on roses (Rosa), and Pediaspidinae (two monotypic genera: Himalocynips and Pediaspis) with poorly known biology, though Pediaspis aceris has been observed inducing galls on maple. These wasps are found in temperate regions across the Northern Hemisphere including Europe, Asia, and North America.