Ectoparasitoid
Guides
Oxyrrhexis
Oxyrrhexis is a genus of ichneumon wasps in the subfamily Pimplinae, tribe Ephialtini, belonging to the Polysphincta genus-group. The genus comprises four described species worldwide. All species are koinobiont ectoparasitoids specialized in attacking spiders, primarily of the family Theridiidae, though one record documents parasitism of a titanoecid spider. The genus was first recorded from Egypt in 2017.
Passandridae
Parasitic Flat Bark Beetles
Passandridae, commonly called parasitic flat bark beetles, is a small family of beetles in the superfamily Cucujoidea. The family contains approximately 109 described species in nine genera. Adults are small to moderately sized beetles (3–35 mm) with heavily sclerotized bodies, typically brown or black in coloration. The family is notable for having larvae that are exclusively ectoparasitic on the immature stages of other beetles and Hymenoptera, making them one of very few beetle families with this lifestyle.
Phygadeuontinae
Darwin wasps
Phygadeuontinae is a subfamily of Darwin wasps within Ichneumonidae, comprising numerous genera including Atractodes, Chirotica, Gelis, Lochetica, and others. The subfamily exhibits cosmopolitan distribution with substantial diversity in the Neotropics, Europe, and Asia Minor. Members are primarily parasitoids with varied host associations including Lepidoptera (Psychidae), Coleoptera (Chrysomelidae), and other insects. The genus Gelis includes at least one documented endoparasitoid of insect eggs, representing an unusual life history strategy for ichneumonids.
Phytodietus
Phytodietus is a species-rich genus of ichneumonid wasps in the subfamily Tryphoninae, distributed across all zoogeographical regions. Members are koinobiont ectoparasitoids of semi-concealed Lepidoptera larvae, with documented associations primarily to Tortricidae and Pyralidae. The genus was recently recorded from Thailand for the first time, expanding Oriental region documentation. Several species have been investigated for biological control of agricultural pests.
Podoschistus vittifrons
Podoschistus vittifrons is the sole North American representative of its genus, a member of the ichneumonid subfamily Poemeniinae. It is an ectoparasitoid wasp that targets wood-boring beetle larvae, using its elongated ovipositor to deposit eggs through solid wood. The species has undergone repeated taxonomic revision, previously assigned to the genera Xorides and Neoxorides. Despite its large size and distinctive appearance, it is rarely encountered in the field.
Poemenia
Poemenia is a genus of ichneumonid wasps in the subfamily Poemeniinae. The genus comprises ectoparasitoids that attack small xylophilous bees (Apoidea) nesting in tunnels or cavities. Larval morphology indicates an ectoparasitoid lifestyle, with the mature larva of Poemenia albipes being the first described for the genus.
Poemeniinae
Poemeniinae is a small subfamily of ichneumonid wasps (Hymenoptera: Ichneumonidae) established by Narayanan & Lal in 1953. Members are ectoparasitoids of wood-boring insects, with hosts including beetle larvae (Cerambycidae, Buprestidae) and xylophilous bees (Apoidea). The subfamily exhibits high local species richness in undisturbed forest habitats, particularly in the Carpathian Mountains where up to 95 species of the broader pimpliform group have been documented in a single 250-hectare forest patch. Taxonomic stability has been limited, with genera such as Podoschistus historically transferred between Xorides, Neoxorides, and other groupings.
Polyblastus
Polyblastus is a genus of ichneumon wasps in the subfamily Tryphoninae. Females are koinobiont ectoparasitoids of sawfly larvae, carrying multiple small eggs externally on the ovipositor or abdomen. The genus has been documented in Europe and North America, with field observations in northern Germany and Colorado, USA. Some species have been observed with egg clusters attached to foliage, though the function of this behavior remains unclear.
Polyblastus tibialis
A species of ichneumon wasp in the subfamily Tryphoninae. Documented from western Canada with records from Alberta. Belongs to a genus of koinobiont ectoparasitoids that attack sawfly larvae. The specific epithet 'tibialis' likely refers to a characteristic of the tibia.
Pompiloidea
Spider Wasps, Velvet Ants, and Allies
Pompiloidea is a superfamily within Hymenoptera comprising four extant families: Pompilidae (spider wasps), Mutillidae (velvet ants), Myrmosidae (myrmosid wasps), and Sapygidae (sapygid wasps). Members are primarily solitary wasps, many of which are ectoparasitoids. The superfamily also includes the extinct family Burmusculidae, known from Cretaceous amber.
Pristocera
Pristocera is a genus of chrysidoid wasps in the family Bethylidae, distributed across the Old World. Males are distinguished by a hypopygium split into two separate plates, while females possess petiolar flaps. The genus comprises numerous species, with documented diversity in Africa, Asia, and Papua New Guinea. At least one species, Pristocera rufa, is known to be a gregarious ectoparasitoid of weevil larvae.
Pseudogaurax
Pseudogaurax is a genus of small flies in the family Chloropidae (frit flies), established by Malloch in 1915. The genus contains approximately 70 described species distributed across all biogeographic regions, with particular diversity in the Neotropics. Larvae are specialized predators and parasitoids of arthropod eggs, with well-documented associations with spider egg sacs, dobsonfly egg masses, mantid oothecae, and—uniquely among Chloropidae—ants. The genus includes the first known ant-parasitizing species in its family, Pseudogaurax paratolmos, discovered in Panama in 2016.
Pseudogaurax signatus
frit fly
Pseudogaurax signatus is a species of frit fly in the family Chloropidae, first described by Loew in 1876. The species has been documented as a parasite of spider egg sacs, specifically those of the black and yellow garden spider Argiope aurantia. This parasitic relationship was recorded in a 1993 study by Lockley and Young, which identified P. signatus as one of the chief parasites emerging from A. aurantia egg sacs alongside the ichneumon wasp Tromatopia rufopectus. The species belongs to a genus that includes other parasitoid members, with the congeneric species Pseudogaurax paratolmos being the first chloropid fly discovered to parasitize ants.
Rhopalosoma
cricket parasitoid wasps
Rhopalosoma is a genus of aculeate wasps in the family Rhopalosomatidae, comprising 18 described species distributed primarily in the Neotropics and southern Nearctic. Larvae develop as ectoparasitoids of crickets (Orthoptera: Gryllidae, Trigonidiidae), attaching externally to host nymphs or adults. Adults are rarely encountered in the field and are among the least known of all parasitoid wasps. Genetic studies indicate the presence of cryptic species diversity, with at least two genetically distinct lineages present in America north of Mexico.
Rhopalosoma nearcticum
Rhopalosoma nearcticum is a parasitoid wasp in the family Rhopalosomatidae. Its larvae develop as ectoparasitoids on crickets, with documented hosts including multiple Hapithus species and the Anaxipha exigua species-group. The species is found in the Americas from the United States to Brazil, though phylogenetic studies suggest at least two genetically distinct Rhopalosoma clades exist in America north of Mexico.
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Rhopalosomatid Wasps
Rhopalosomatidae is a small family of aculeate wasps containing approximately 68 extant species in four genera: Rhopalosoma, Olixon, Liosphex, and Paniscomima. Adults are solitary and often ant-like in appearance. Larvae are obligate ectoparasitoids of crickets (Orthoptera: Grylloidea), attaching to the lateral side of the host between the metafemur and abdomen. The family exhibits remarkable morphological diversity, with winged species typically nocturnal and brachypterous species mainly diurnal. The family has a worldwide tropical and subtropical distribution, absent from Europe and Antarctica.
Rhysipolinae
Rhysipolinae is a small cosmopolitan subfamily of braconid wasps comprising approximately 10 genera and more than 80 species. Members are cyclostome wasps characterized by koinobiont ectoparasitoid biology—a rare strategy among Braconidae that deviates from the more common koinobiont-endoparasitoid or idiobiont-ectoparasitoid modes. The subfamily has been taxonomically challenging due to the absence of exclusive morphological diagnostic features, though recent phylogenomic analyses using ultraconserved elements have confirmed its monophyly and clarified some generic boundaries.
Rhysipolis
Rhysipolis is a genus of parasitoid wasps in the subfamily Rhysipolinae (Braconidae), comprising approximately 22 described species. Species are small, with body lengths of 2.5–4.0 mm and fore wing lengths of 2.2–4.0 mm. The genus is distributed across the East Palaearctic and Oriental regions, with records from China, Russia, Taiwan, Hong Kong, and parts of Europe. Members are koinobiont ectoparasitoids of lepidopteran larvae, with documented hosts including bagworm moths (Psychidae) and snout moths (Pyralidae).
Sclerodermus
Flat wasp
Sclerodermus is a genus of small parasitoid wasps in the family Bethylidae, comprising at least 20 described species. These wasps exhibit quasi-social behavior rare among parasitoids: multiple females cooperate to paralyze hosts and provision shared broods with extended maternal care. Most individuals are wingless, leading to frequent misidentification as ants. The genus is notable for extremely female-biased sex ratios (often 86-97% female) and has significant value as biological control agents against wood-boring beetles, particularly in forestry systems.
Scolioidea
Scoliid Wasp Superfamily
Scolioidea is a superfamily of Hymenoptera containing the family Scoliidae, a group of medium-sized wasps with approximately 560 species worldwide. The family is predominantly distributed in tropical and subtropical regions, with 64 species recorded in the New World. Scoliidae are ectoparasitoids of Scarabaeoidea larvae, particularly Melolonthinae (scarab beetles), which they immobilize and parasitize in terrestrial larval galleries. The superfamily has been taxonomically understudied in the Americas, with limited keys and ambiguous historical descriptions.
Spathius
Spathius is a genus of doryctine wasps in the family Braconidae. Species within this genus are larval parasitoids of wood-boring beetles, with several species introduced to North America as biological control agents for the invasive emerald ash borer (Agrilus planipennis). The genus includes both native and introduced species that exhibit host-specific relationships with their beetle hosts.
Sphaeropthalma blakeii
Sphaeropthalma blakeii is a species of velvet ant in the family Mutillidae, first described by Fox in 1893. The genus Sphaeropthalma is among the most diverse mutillid genera in North America. Like all velvet ants, females are wingless and wasp-like in appearance, while males possess wings. The species is poorly documented in the literature, with limited information available beyond taxonomic records.
Sphecophaga
Sphecophaga is a genus of ichneumonid wasps specialized as ectoparasitoids of vespid wasps. Species within this genus parasitize nests of social wasps, with larvae feeding externally on immature wasp pupae. The genus exhibits complex polymorphism in adult forms and cocoon types, and has been widely introduced as a biological control agent for invasive Vespula wasp species. Two recognized species occur: S. orientalis parasitizing Vespa orientalis in the Mediterranean region, and S. vesparum with subspecies in Europe and North America targeting Vespula species.
Sphecophaga vesparum
Sphecophaga vesparum is an ichneumonid ectoparasitoid of vespid wasps, primarily targeting Vespula vulgaris and Vespula germanica. The species exhibits remarkable developmental plasticity with two adult female morphs: large winged females and small brachypterous females, each emerging from distinct cocoon types. It has been introduced to New Zealand and Australia as a biological control agent for invasive social wasps. The species is facultatively deuterotokous, producing mostly parthenogenetic females with occasional males.
Stenarella
Stenarella is a genus of ichneumonid wasps in the subfamily Cryptinae, subtribe Osprynchotina. The genus is monophyletic and distributed across the Old World, with three major biogeographic clades corresponding to the Afrotropical, Palearctic, and Oriental–Australasian regions. Eighteen species are currently recognized, twelve described as new in a 2025 phylogenomic revision. Species are ectoparasitoids of aculeate Hymenoptera that construct nests using mud or earth.
Stenarella domator
Stenarella domator is a western Palaearctic ichneumonid wasp recently introduced to the Nearctic region. It belongs to the subtribe Osprynchotina within the subfamily Cryptinae. The species is an ectoparasitoid that targets aculeate Hymenoptera nesting in mud or earth substrates. Its establishment in North America represents a notable range expansion for this parasitoid lineage.
Symphrasinae
thorny lacewings
Symphrasinae is a subfamily of thorny lacewings within Rhachiberothidae (Neuroptera), recently transferred from Mantispidae. It comprises three genera—Anchieta, Plega, and Trichoscelia—with 60 described species distributed exclusively in the New World from the southwestern United States to southern Argentina. Members possess raptorial forelegs for prey capture. The genus Plega has been documented as an ectoparasitoid of sawfly larvae and pupae.
Sympiesis
Sympiesis is a genus of small parasitoid wasps in the family Eulophidae. Species are primarily ectoparasitoids of lepidopteran larvae, particularly leaf-mining moths in the family Gracillariidae, though some species attack other caterpillar groups including Hesperiidae (skippers) and Hyblaeidae. Several species have been studied for their potential as biological control agents of agricultural pests. The genus has been documented from North America, Europe, and South Asia.
Tamarixia
Tamarixia is a genus of small parasitoid wasps in the family Eulophidae, primarily known as parasitoids of psyllids (jumping plant lice, superfamily Psylloidea). The genus was established by Mercet in 1924 and contains approximately 50 described species distributed worldwide. Most species are ectoparasitoids, though at least one species has been recorded as an endoparasitoid. Several species, particularly T. radiata and T. triozae, are important biological control agents used in integrated pest management programs for citrus and solanaceous crops.
Theocolax
Theocolax is a genus of small parasitic wasps in the family Cerocephalidae. The genus includes multiple species, with T. elegans being the most extensively studied. Members are ectoparasitoids of stored product insect pests, particularly beetles and moths that develop inside cereal and leguminous grains. They are cosmopolitan in distribution and have been investigated for biological control applications in grain storage facilities.
Tryphonini
Tryphonini is a tribe of koinobiont ichneumonid wasps within the subfamily Tryphoninae. Members are ectoparasitoids of sawfly larvae (Hymenoptera: Symphyta), with females possessing relatively large egg loads compared to idiobiont relatives. The genus Polyblastus is a well-documented member of this tribe. Females have been observed carrying egg clusters externally, possibly due to egg retention after unsuccessful oviposition attempts.
Xoridinae
Xoridine wasps
Xoridinae is a worldwide subfamily of Ichneumonidae containing approximately 220 described species in four genera: Xorides, Odontocolon, Ischnoceros, and Aplomerus. These wasps are idiobiont ectoparasitoids that specialize on wood-boring beetle larvae, particularly Cerambycidae and Buprestidae, and occasionally Hymenoptera (Symphyta). They are strongly associated with mature forest habitats and are considered important biological control agents of forest pests.
Zatypota
Zatypota is a genus of ichneumonid wasps comprising at least 40 described species, distributed across Europe, Asia, and the Americas. All species are koinobiont ectoparasitoids of spiders, primarily targeting theridiid spiders though some species parasitize linyphiids and araneids. The genus is notable for inducing behavioral manipulation in host spiders, causing them to construct specialized "cocoon webs" that protect the developing wasp larva. Several species have been documented as hosts for hyperparasitoid chalcidid wasps, forming complex three-trophic-level interactions.