Gall Wasp Species Research Articles

Aulacidea manchuria Nastasi sp. nov., a new herb gall wasp from China (Hymenoptera: Cynipoidea: Aulacideini), with commentary on hawkweed (Asteraceae: Hieraciinae) gall wasps

We describe Aulacidea manchuria Nastasi sp. nov., a new species of herb gall wasp from China and the second species of Aulacidea Ashmead, 1897 to be described from the country. Based on morphological data, A. manchuria belongs to the Aulacidea hieracii group, which is known to induce galls on the stems, leaves, and stolons of Hieracium L. and Pilosella Hill; we provide a key to Eastern Palearctic females of this species group to better enable identification of these species. We discuss records of herb gall wasps from China, the recognition of hawkweed gall wasp species, and further issues with taxonomy of this species group and of Aulacidea.

Description of a new species of Andricus Hartig, 1840 (Hymenoptera: Cynipidae: Cynipini) from China

A new species of gall wasp, Andricus wugangensis Zeng, Liu, & Zhu sp. nov. is described and illustrated herein from Hunan Province, China. The new species is most similar to A. wuhanensis Ide, Abe, Su & Zhu and A. xishuangbanaensis Melika & Tang in morphology but can be easily distinguished by having 1) a large V-shaped carina on the lower face and 2) a broad transverse depression spanning the region between the inner margin of the eyes on the upper face. The results of a phylogenetic analysis and pairwise genetic distance comparison, based on COI sequences, were consistent with the conclusion of the comparative morphological assessment of the similar species: A. wuganensis, A. wuhanensis and A. xishuangbanaensis, although the morphological differences are more obvious than the small genetic distance of the COI sequences, which is 4.3% and 3% between the new species and A. wuhanensis and A. xishuangbanaensis, respectively. Additionally, a taxonomic key to the known species of Andricus from China is provided.

New species of gall wasps (Hymenoptera: Cynipidae: Aulacideini and Phanacidini) inducing galls on plants of the genera Sonchus and Crepis (Asteraceae) in Romania (Dobrogea Province) and notes on their parasitoids

Two new species of herb gall wasps (Hym., Cynipidae) developing on plants in the genera Sonchus L. and Crepis L. (Asteraceae) are described from Southeastern Romania (Dobrogea Province): Aulacidea andriescui sp. n. gall inducer on Sonchus palustris L. and Phanacis dobrogicus sp. n. gall maker on Crepis foetida subsp. rhoeadifolia (M. Bieb.) Čelak. In addition to the diagnosis, identification, morphological description, life-cycle, geographical distribution, photos of gall and host plant, and SEM images, data on the associated fauna obtained from the galls of the two new species are also presented.

Description and mitochondrial genome sequencing of a new species of inquiline gall wasp, Synergus nanlingensis (Hymenoptera, Cynipidae, Synergini), from China

A new species of inquiline gall wasp, Synergus nanlingensis Wang & Zeng, sp. nov., which was reared from galls on Castanopsis eyrei Tutch (Fagaceae) collected in Guangdong Province, China, is described and illustrated herein along with its mitochondrial genome. The mitogenome of S. nanlingensis is 16,604 base pairs in length and comprises 37 genes, which is typical of mitogenomes. One large control region was detected in the S. nanlingensis mitogenome, which differed from that reported for other Cynipidae species. Similar to other Cynipidae species, S. nanlingensis has the same four common gene rearrangement events; however, it shows some differences, as follows: trnS1 is downstream of Cytb; trnS2 is upstream of nad1; and trnC is downstream of rrnS. Phylogenetic analysis using COI, CytB, and 28S-D2 sequences confirmed that S. nanlingensis is a distinct species belonging to the genus Synergus Hartig.

Description of the first species of gall wasp (Hym., Cynipidae: Cynipini) on Quercus grahamii (Fagaceae).

A new species of oak gall wasp, Andricus coombesi Pujade-Villar & Prez-Torres n. sp. from Mexico, known only from its asexual generation that induces galls on acorns of Quercus grahamii Benth., (section Lobatae) is described. Its presence causes the complete disappearance of the acorn. Diagnosis, distribution and biological data of the new species are given. Andricus coombesi Pujade-Villar & Prez-Torres n. sp. represents the first gall wasp species mentioned from this host.

Reproductive Parameters and Host Specificity of Eurytoma erythrinae (Hymenoptera: Eurytomidae), a Biological Control Agent of the Erythrina Gall Wasp, Quadrastichus erythrinae (Hymenoptera: Eulophidae).

Eurytoma erythrinae Gates & Delvare (Hymenoptera: Eurytomidae) is an important biological control agent of the erythrina gall wasp (EGW), Quadrastichus erythrinae Kim (Hymenoptera: Eulophidae), an invasive species likely originating in eastern Africa that is a threat to Erythrina trees in Hawaii and worldwide. Thousands of Erythrina trees in Hawaii have succumbed to EGW since 2005 and died within a few years of infestation. The endemic wiliwili tree, Erythrina sandwicensis, an important component of Hawaii's dry forests and one of few deciduous native trees, were severely impacted by this wasp. Early during the invasion by EGW it became evident that the endemic species may be driven to extinction, and exploration programs for natural enemies of the EGW started in December 2005. East Africa was selected as the starting point for natural enemy exploration owing to high native Erythina species richness. Several gall formers were found in Tanzania and a putative color variant type of Q. erythrinae was detected in association with three ectoparasitoids. During January 2006, the dominant parasitoid of this gall former was introduced to Hawaii and described as the new species, E. erythrinae. It was found in Ghana and South Africa attacking other gall wasp species on Erythrina. Eurytoma erythrinae was a voracious ectoparasitoid feeding as a predator on 1-5 adjacent EGW immatures to complete its development. Host specificity studies that included seven nontarget gall-forming species showed no evidence of attraction or parasitism by this parasitoid. Mean ± SEM longevity of host-deprived females (40.4 ± 2.2 days) was significantly higher than males (20.5 ± 1.1 days). Host feeding enhanced longevity of ovipositing females (51.3 ± 1.5 days). Female E. erythrinae is synovigenic, with high egg-maturation rate. Peak fecundity (105-239 offspring/female), host feeding biology, short life cycle (18.4 ± 0.1 days), and synchronization with the host were additional desirable attributes of this species. The parasitoid was approved for field release in Hawaii in November 2008. A total of 3998 wasps were distributed on six Hawaiian Islands, with establishment in less than a year. Impacts on high density infestations of EGW were sufficient to prevent tree deaths. Limited rates of parasitism on low-density galled leaves, flowers, and seedpods necessitated the consideration for releasing a second parasitoid, Aprostocetus nitens Prinsloo & Kelly (Hymenoptera: Eulophidae). We report on the reproductive characteristics and host specificity of E. erythinae that could be of importance for classical biocontrol programs in areas with an EGW problem.

Speciation in kleptoparasites of oak gall wasps often correlates with shifts into new tree habitats, tree organs, or gall morphospace.

Host shifts to new plant species can drive speciation for plant-feeding insects, but how commonly do host shifts also drive diversification for the parasites of those same insects? Oak gall wasps induce galls on oak trees and shifts to novel tree hosts and new tree organs have been implicated as drivers of oak gall wasp speciation. Gall wasps are themselves attacked by many insect parasites, which must find their hosts on the correct tree species and organ, but also must navigate the morphologically variable galls with which they interact. Thus, we ask whether host shifts to new trees, organs, or gall morphologies correlate with gall parasite diversification. We delimit species and infer phylogenies for two genera of gall kleptoparasites, Synergus and Ceroptres, reared from a variety of North American oak galls. We find that most species were reared from galls induced by just one gall wasp species, and no parasite species was reared from galls of more than four species. Most kleptoparasite divergence events correlate with shifts to non-ancestral galls. These shifts often involved changes in tree habitat, gall location, and gall morphology. Host shifts are thus implicated in driving diversification for both oak gall wasps and their kleptoparasitic associates.

The formation of a rolling larval chamber as the unique structural gall of a new species of cynipid gall wasps

Insect galls, which often have complex external and internal structures, are believed to have adaptive significance for the survival of insects inside galls. A unique internal structure was discovered in the gall of a new cynipid species, Belizinella volutum Ide & Koyama, sp. nov., where the larval chamber could roll freely in the internal air space of the gall. Observations of the live galls using micro-computed tomography (micro-CT) revealed its formation process. The larval chamber becomes isolated from the internal parenchyma soon after the gall reaches the maximum diameter and is able to roll as the internal air space is expanding from the surrounding parenchyma to the outer gall wall. The enemy hypothesis could partly explain the adaptive significance of the unique structure of the gall of B. volutum.

The complete mitochondrial genome and gene rearrangements in a gall wasp species, Dryocosmus liui (Hymenoptera: Cynipoidea: Cynipidae).

Mitochondrial genomes (mitogenomes) have been widely used in comparative and evolutionary genomics, molecular evolution, phylogenetics, and population genetics, but very limited information is available for the family Cynipidae. In this report, we describe the mitogenome of Dryocosmus liui Pang, Su et Zhu, providing the first complete mitogenomic data for a cynipid gall wasp species. The mitogenome of D. liui is 16,819 bp in length, and contains the typical set of 37 genes. Two control regions were detected, with the second being a perfect inverted repeat of the major portion of the first. Gene rearrangements were found in transfer RNA (tRNA) genes, protein-coding genes (PCGs) and ribosomal RNA (rRNA) genes, compared with the putative ancestral mitogenome. Similar to two other Cynipidae species with mitogenome data available, D. liui has a novel tRNA gene cluster trnL1-trnI-trnL2-trnW-trnM-trnQ between nad1 and nad2. Phylogenetic analysis based on sequences of PCGs and rRNA genes with D. liui included obtained topologies identical to previous studies supporting the a relationship of (Cynipoidea , (Platygastroidea, Proctotrupoidea)) within the monophyletic Proctotrupomorpha and (Cynipidae, Figitidae), Ibaliidae) within the Cynipoidea.

Host–enemy interactions provide limited biotic resistance for a range‐expanding species via reduced apparent competition

AbstractAimAs species' ranges shift poleward in response to anthropogenic change, they may lose antagonistic interactions if they move into less diverse communities, fail to interact with novel populations or species effectively, or if ancestral interacting populations or species fail to shift synchronously. We leveraged a poleward range expansion in a tractable insect host–enemy community to uncover mechanisms by which altered antagonistic interactions between native and recipient communities contributed to ‘high niche opportunities’ (limited biotic resistance) for a range‐expanding insect.LocationNorth America, Pacific Northwest.MethodsWe created quantitative insect host–enemy interaction networks by sampling oak gall wasps on 400 trees of a dominant oak species in the native and expanded range of a range‐expanding gall wasp species. We compared host–enemy network structure between regions. We measured traits (phenology, morphology) of galls and interacting parasitoids, predicting greater trait divergence in the expanded range. We measured function relating to host control and explored if altered interactions and traits contributed to reduced function, or biotic resistance.ResultsInteraction networks had fewer species in the expanded range and lower complementarity of parasitoid assemblages among host species. While networks were more generalized, interactions with the range‐expanding species were more specialized in the expanded range. Specialist enemies effectively tracked the range‐expanding host, and there was reduced apparent competition with co‐occurring hosts by shared generalist enemies. Phenological divergence of enemy assemblages interacting with the range‐expanding and co‐occurring hosts was greater in the expanded range, potentially contributing to weak apparent competition. Biotic resistance was lower in the expanded range, where fewer parasitoids emerged from galls of the range‐expanding host.Main ConclusionsChanges in interactions with generalist enemies created high niche opportunities, and limited biotic resistance, suggesting weak apparent competition may be a mechanism of enemy release for range‐expanding insects embedded within generalist enemy networks.

The role of Anatolia between Asia and Europe: A case study of oak gall wasp species, Cynips quercus (Hymenoptera, Cynipidae)

In this study, we used DNA sequence data of a western Palearctic oak gall wasp species, Cynips quercus, showing distribution from Europe to Iran to answer the following questions: i) Do the eastern C. quercus populations have higher genetic diversity than the European populations?, ii) Are the eastern populations source for the European populations?, iii) What is the possible date of divergence between the Asian and European populations? For these purposes, we analysed 88 cytochrome b sequences representing Iran, Türkiye, Hungary, and Spain. Our analyses revealed that the highest genetic diversity was in Türkiye followed by Iran, Hungary, and Spain, respectively. Iranian samples were most divergent from the Spain and Hungary sequences. Pairwise comparisons showed that the highest gene flow was between Türkiye and Hungary, and between Türkiye and Iran, respectively. Phylogenetic analysis grouped the Turkish haplotypes with the Iranian sequences, and Spain was grouped with Hungary. Network analysis revealed that the western Turkish samples were separated from eastern sequences, and all of the eastern Turkish sequences were clustered with the Iranian samples meanwhile a western Turkish lineage provided a source to Hungary and then to Spain. Times of divergence analysis estimated that the Turkish lineage split from the Iranian lineage around 4,67 million years ago, and Hungarian and Spanish lineages diverged from each other about 3 million years ago. Correspondingly, our analyses suggested that Anatolia played a key role as a bridge between the Asian and European populations of C. quercus.

A new species of Andricus Hartig, 1840 (Hymenoptera, Cynipidae) from China, with references to DNA taxonomy and Wolbachia infection.

In the present paper, a new species of cynipid gall wasp, Andricuselodeoides Liu & Pang, is described from several provinces in southern China. The new species is closely related to the recently redescribed A.mairei (Kieffer, 1906). In addition to differences in adult and gall morphology, the new species is also readily separated by COI sequences, with a 6.2-8.9% genetic distance between populations of the new species and those of A.mairei. A contrasting difference in sex ratios was also observed between the two species, with A.elodeoides extremely female-biased (95.5-97.8% female) while A.mairei male-biased to more balanced (5.4-43.5% female). PCR screening for Wolbachia infection further revealed contrasting infection rates between populations of A.elodeoides and A.mairei: the Wolbachia infection rate was 0% in A.elodeoides and 100% in A.mairei. Cytoplasmic incompatibility induced by Wolbachia is proposed as a potential mechanism of speciation of the sympatric A.elodeoides and A.mairei.

Andricus protuberans Pujade-Villar & Ferrer-Suay IS A SEXUAL FORM (HYM., CYNIPIDAE, CYNIPINI)

We describe and illustrate the morphological characters of the male of Andricus protuberans Pujade-Villar & Ferrer-Suay, 2015 (Hymenoptera, Cynipidae), an oak gall wasp species considered an asexual generation in the original description. The reasons for this mistake are discussed, and the variability of this species in the metasomal segments is mentioned.

Survey of Cynipid Gall Wasps (Hymenoptera, Cynipidae) in Serbia

A list of 72 species of cynipid gall wasps that have been recorded to date in Serbia was compiled on the basis of studying cynipid fauna during the period from 2003 to 2020 and previously published data. The species Andricus quercusramuli (Linnaeus 1761) and Pediaspis aceris (Gmelin 1790) are recorded for the first time in the fauna of Serbia. The fauna of cynipid gall wasps in Serbia has still not been thoroughly studied. It is excepted that about 40 to 50 species new to the fauna will be found.

Speciation in Nearctic oak gall wasps is frequently correlated with changes in host plant, host organ, or both.

Quantifying the frequency of shifts to new host plants within diverse clades of specialist herbivorous insects is critically important to understand whether and how host shifts contribute to the origin of species. Oak gall wasps (Hymenoptera: Cynipidae: Cynipini) comprise a tribe of ∼1000 species of phytophagous insects that induce gall formation on various organs of trees in the family Fagacae—primarily the oaks (genus Quercus; ∼435 sp.). The association of oak gall wasps with oaks is ancient (∼50 my), and most oak species are galled by one or more gall wasp species. Despite the diversity of both gall wasp species and their plant associations, previous phylogenetic work has not identified the strong signal of host plant shifting among oak gall wasps that has been found in other phytophagous insect systems. However, most emphasis has been on the Western Palearctic and not the Nearctic where both oaks and oak gall wasps are considerably more species rich. We collected 86 species of Nearctic oak gall wasps from most of the major clades of Nearctic oaks and sequenced >1000 Ultraconserved Elements (UCEs) and flanking sequences to infer wasp phylogenies. We assessed the relationships of Nearctic gall wasps to one another and, by leveraging previously published UCE data, to the Palearctic fauna. We then used phylogenies to infer historical patterns of shifts among host tree species and tree organs. Our results indicate that oak gall wasps have moved between the Palearctic and Nearctic at least four times, that some Palearctic wasp clades have their proximate origin in the Nearctic, and that gall wasps have shifted within and between oak tree sections, subsections, and organs considerably more often than previous data have suggested. Given that host shifts have been demonstrated to drive reproductive isolation between host‐associated populations in other phytophagous insects, our analyses of Nearctic gall wasps suggest that host shifts are key drivers of speciation in this clade, especially in hotspots of oak diversity. Although formal assessment of this hypothesis requires further study, two putatively oligophagous gall wasp species in our dataset show signals of host‐associated genetic differentiation unconfounded by geographic distance, suggestive of barriers to gene flow associated with the use of alternative host plants.

Description of Fumariphilus Nieves-Aldrey, gen. nov., a new genus of herb gall wasps, with a key to genera of the tribe Aulacideini (Hymenoptera: Cynipidae).

A new genus of herb gall wasps, Fumariphilus Nieves-Aldrey gen. nov., (Hymenoptera, Cynipidae, Aulacideini), is described. Previous molecular phylogenetic analyses, and resulting systematic changes at the tribe level, have shown that the related species Aylax hypecoi Trotter and Neaylax versicolor Nieves-Aldrey have been incorrectly placed within their respective genera. In order to reflect their monophyletic lineage and to accommodate these species within the tribe Aulacideini, it is necessary to erect a new genus. The two species, Fumariphilus versicolor (Nieves-Aldrey, 1985) n. comb. and Fumariphilus hypecoi (Trotter, 1913) n. comb. placed in the new genus induce galls in fruits of species of, respectively, Hypecoum L. (Papaveraceae: Fumarioideae: Hypecoeae) and Fumaria L. (Papaveraceae: Fumarioideae: Fumarieae), reflecting a host-plant association that is unique among all the cynipids. Diagnostic morphological features of both the adult and the larvae and an identification key to the species of the new genus are provided. Adults of Fumariphilus versicolor n. comb., are also re-described and, for both species of Fumariphilus, the terminal instar larva is described and illustrated with SEM images. Following the erection of the new genus Fumariphilus, Aylax Hartig, sensu Nieves-Aldrey, 1994 is now sufficiently delimited within the tribe Aylacini sensu stricto Ashmead, 1903, which comprises species associated with only plants of the genus Papaver (Papaveraceae). Likewise, Neaylax Nieves-Aldrey, 1994, which now includes only the gall wasp species that associate with species of Salvia (Lamiaceae), is sufficiently delimited within the tribe Aulacideini Nieves-Aldrey, Nylander Ronquist, 2015. Also provided in this work is an updated and illustrated identification key to the genera of the Aulacideini.

A new species of oak gall wasp (Hymenoptera: Cynipidae, Cynipini) from Turkey.

A new species of the genus Andricus Hartig, 1840 (Cynipidae: Cynipini) is described from Burdur province in Turkey: Andricus arslani Azmaz Katlm sp. n. sexual generation. The new species induce galls on Quercus cerris L. belonging to section Cerris. SEM images, photos of the host galls, and data on the diagnosis, distribution, and biology of the new species are provided.

Describing biodiversity in the genomics era: A new species of Nearctic Cynipidae gall wasp and its genome

ABSTRACTGall wasps (Hymenoptera: Cynipidae) specializing on live oaks in the genus Quercus (subsection Virentes) are a relatively diverse and well‐studied community with 14 species described to date, albeit with incomplete information on their biology, life history and genetic structure. Incorporating an integrative taxonomic approach, we combine morphology, phenology, behaviour, genetics and genomics to describe a new species, Neuroterus valhalla sp. nov. The alternating generations of this species induce galls on the catkins and stem nodes of Quercus virginiana and Quercus geminata in the southern United States. We describe both generations in the species' life cycle, and primarily use samples from a population in the centre of Houston, Texas, thus serving as an example of the undescribed biodiversity still present in well‐travelled urban centres. In parallel, we present a draft assembly of the N. valhalla genome providing a direct link between the type specimen and reference genome. The genome of N. valhalla is the smallest reported to date within the tribe Cynipini, providing an important comparative contrast to the otherwise large genome size of cynipids. While relatively small, the genome was found to be composed of >64% repetitive elements, including 43% unclassified repeats and 11% retrotransposons. A preliminary ab initio and homology‐based annotation revealed 32,005 genes, and a subsequent orthogroup analysis grouped 18,044 of these to 8186 orthogroups, with some evidence for high levels of gene duplications within Cynipidae. A mitochondrial barcode phylogeny linked each generation of the new species and a phylogenomic ultraconserved element (UCEs) phylogeny indicates that the new species groups with other Nearctic Neuroterus. However, both phylogenies present the genus Neuroterus in North America as polyphyletic.

The Arthropod Associates of 155 North American Cynipid Oak Galls.

The identities of most arthropod associates of cynipid-induced oak galls in the western Palearctic are generally known. However, a comprehensive accounting of associates has been performed for only a small number of the galls induced by the estimated 700 species of cynipid gall wasps in the Nearctic. This gap in knowledge stymies many potential studies of diversity, coevolution, and community ecology, for which oak gall systems are otherwise ideal models. We report rearing records of insects and other arthropods from more than 527,306 individual galls representing 201 different oak gall types collected from 32 oak tree species in North America. Of the 201 gall types collected, 155 produced one or more arthropods. A total of 151,075 arthropods were found in association with these 155 gall types, and of these 61,044 (40.4%) were gall wasps while 90,031 (59.6%) were other arthropods. We identified all arthropods to superfamily, family, or, where possible, to genus. We provide raw numbers and summaries of collections, alongside notes on natural history, ecology, and previously published associations for each taxon. For eight common gall-associated genera (Synergus, Ceroptres, Euceroptres, Ormyrus, Torymus, Eurytoma, Sycophila, and Euderus), we also connect rearing records to gall wasp phylogeny, geography, and ecology -including host tree and gall location (host organ), and their co-occurrence with other insect genera. Though the diversity of gall wasps and the large size of these communities is such that many Nearctic oak gall-associated insects still remain undescribed, this large collection and identification effort should facilitate the testing of new and varied ecological and evolutionary hypotheses in Nearctic oak galls.

Andricus partali n. sp. from Costa Rica (Hymenoptera: Cynipidae: Cynipini)

A new species of oak gallwasp, Andricus partali n. sp. (Hym., Cynipidae: Cynipini), is described from Costa Rica inducing galls on the leaves of Q. costaricensis Liebm. (Section Lobatae). We provide a description, diagnosis, and information about the distribution and biology of the new species.