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 & Katılmış 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.

Two new oak gall wasp species (Hymenoptera: Cynipidae, Cynipini) from Quercus pontica (Fagaceae) in Turkey

Two new species of oak gall wasp, Andricus mammadovi Azmaz & Katılmış sp. n. sexual generation and Cynips fatihi Azmaz & Katılmış sp. n. asexual generation (Cynipidae: Cynipini) are described from the eastern Black Sea region in Turkey. These species induce galls on Quercus pontica K.Koch representing the first record of cynipids associated with the natural Q. pontica population in Turkey. SEM images, photos of the host galls, and data on the diagnosis, distribution, and biology of both new species are provided.

Massive colonization of protein-coding exons by selfish genetic elements in Paramecium germline genomes

Ciliates are unicellular eukaryotes with both a germline genome and a somatic genome in the same cytoplasm. The somatic macronucleus (MAC), responsible for gene expression, is not sexually transmitted but develops from a copy of the germline micronucleus (MIC) at each sexual generation. In the MIC genome of Paramecium tetraurelia, genes are interrupted by tens of thousands of unique intervening sequences called internal eliminated sequences (IESs), which have to be precisely excised during the development of the new MAC to restore functional genes. To understand the evolutionary origin of this peculiar genomic architecture, we sequenced the MIC genomes of 9 Paramecium species (from approximately 100 Mb in Paramecium aurelia species to >1.5 Gb in Paramecium caudatum). We detected several waves of IES gains, both in ancestral and in more recent lineages. While the vast majority of IESs are single copy in present-day genomes, we identified several families of mobile IESs, including nonautonomous elements acquired via horizontal transfer, which generated tens to thousands of new copies. These observations provide the first direct evidence that transposable elements can account for the massive proliferation of IESs in Paramecium. The comparison of IESs of different evolutionary ages indicates that, over time, IESs shorten and diverge rapidly in sequence while they acquire features that allow them to be more efficiently excised. We nevertheless identified rare cases of IESs that are under strong purifying selection across the aurelia clade. The cases examined contain or overlap cellular genes that are inactivated by excision during development, suggesting conserved regulatory mechanisms. Similar to the evolution of introns in eukaryotes, the evolution of Paramecium IESs highlights the major role played by selfish genetic elements in shaping the complexity of genome architecture and gene expression.

The Heterogonic Life Cycles of Oak Gall Wasps Need to Be Closed: A Lesson From Two Species of Dryophanta (Hymenoptera: Cynipidae: Cynipini)

In heterogonic gall wasps, the gall structure, phenology, and adult morphology differ between the asexual and sexual generations, even within the same species. Dryophanta japonica Ashmead and Dryophanta mitsukurii Ashmead were described in 1904, but their heterogonic life cycles were uncertain. To match their asexual and sexual generations, we compared the type specimens of both species with specimens of gall wasps reared to demonstrate heterogonic life cycles. This revealed that these two species are the respective asexual and sexual generations of a single heterogonic species. Based on the morphological characteristics, we transferred D. japonica to Cerroneuroterus Melika and Pujade-Villar as Cerroneuroterus japonicus (Ashmead, 1904) comb. nov. and treated the sexual generation as a junior synonym: Dryophanta mitsukurii Ashmead, 1904 syn. nov. Moreover, we examined the type specimens of other species previously suggested to be synonymous with D. mitsukurii. This showed that Neuroterus vonkuenburgi Dettmer, 1934 syn. nov. (and N. vonkuenburgi wakayamensis Monzen, 1954 syn. nov.) is the asexual generation of C. japonicus and that Neuroterus bonihenrici Dettmer, 1934 syn. nov. is the sexual generation. Judging from the original descriptions, Andricus asakawae Shinji, 1943 syn. nov., Andricus kanagawae Shinji, 1943 syn. nov., Andricus asakawae Shinji, 1944 syn. nov., Andricus kanagawae Shinji, 1944 syn. nov., and Neoneuroterus kashiyamai Monzen, 1954 syn. nov. were also regarded as the sexual generation of C. japonicus. Finally, we discussed how matching asexual and sexual generations in heterogonic gall wasps not only avoids taxonomic confusion but also contributes to progress in gall wasp biology.

Massive colonization of protein-coding exons by selfish genetic elements in Paramecium germline genomes

Ciliates are unicellular eukaryotes with both a germline genome and a somatic genome in the same cytoplasm. The macronucleus (MAC), responsible for gene expression, is not sexually transmitted but develops from a copy of the micronucleus (MIC) at each sexual generation. In the MIC genome of Paramecium tetraurelia, genes are interrupted by tens of thousands of unique intervening sequences, called Internal Eliminated Sequences (IESs), that have to be precisely excised during the development of the new MAC to restore functional genes. To understand the evolutionary origin of this peculiar genomic architecture, we sequenced the MIC genomes of nine Paramecium species (from ~100 Mb in P. aurelia species to > 1.5 Gb in P. caudatum). We detected several waves of IES gains, both in ancestral and in more recent lineages. Remarkably, we identified 24 families of mobile IESs that generated tens to thousands of new copies. The most active families show the signature of horizontal transfer. These examples illustrate how mobile elements can account for the massive proliferation of IESs in the germline genomes of Paramecium, both in non-coding regions and within exons. We also provide evidence that IESs represent a substantial burden for their host, presumably because of excision errors. Interestingly, we observe that IES excision pathways vary according to the age of IESs, and that older IESs tend to be more efficiently excised. This suggests that once fixed in the genome, the presence of IESs imposes a selective pressure on their host, both in cis (on the excision signals of each IES) and in trans (on the cellular excision machinery), to ensure efficient and precise removal. Finally, we identified 69 IESs that are under strong purifying selection across the P. aurelia clade, which indicates that a small fraction of IESs provide a function beneficial for their host. All these features highlight the major role played by selfish elements in shaping the complexity of gene expression processes and in driving genome architecture.

Two new species of oak gall wasps from Turkey (Hymenoptera: Cynipidae, Cynipini)

Two new species of oak gall wasps, Cynips izzetbaysali sp. nov. and Callirhytis afion sp. nov. (Hymenoptera: Cynipidae: Cynipini) are described from Turkey. The new Cynips species is known only from asexual females and induces detachable leaf galls on Quercus infectoria. The sexual generation of the new Callirhytis species is known to induce acorn galls on Quercus cerris. Data on the diagnosis, distribution, and biology of the two new species are given.

A new species of Cerroneuroterus Melika & Pujade-Villar from the Eastern Palaearctic (Hymenoptera, Cynipidae, Cynipini)

A new gall wasp species, Cerroneuroterus yukawamasudai Pujade-Villar & Melika sp. nov., is described from China. The asexual generation induces leaf lenticular galls, and the sexual generation induces catkin galls on Q. acutissima and Q. variabilis. Sexual females and males are not described yet. Data on the diagnosis, distribution, and biology of the new species are provided, including a key to sexual and asexual females of all described Cerroneuroterus species. Previous misidentifications of host galls recorded in Japan are commented on. Molecular analyses were performed to assess the validity of the genus Cerroneuroterus and the affiliation of the new species.

Description of the sexual generation of Dryocosmus destefanii (Hymenoptera: Cynipidae: Cynipini) and disclosure of its life cycle

The sexual generation of Dryocosmus destefanii Cerasa & Melika, 2018 that emerges from galls on Q. suber L. in Italy is described for the first time, establishing its heterogonic life cycle. We provide observations on its distribution, illustration of adults and galls and information on its biology as supported by morphological and molecular data. An illustrated identification key to Western Palaearctic Dryocosmus species is also given.

The reproductive system of the male and oviparous female of a model organism—the pea aphid, Acyrthosiphon pisum (Hemiptera, Aphididae)

The structure of the reproductive system of the sexual generation—males and oviparous females—of the pea aphid Acyrthosiphon pisum (Harris) (Hemiptera, Aphididae), a serious pest of cultivated plants of Fabaceae, was investigated. For the first time we describe the morphology, histology and ultrastructure of the reproductive system in both morphs of the sexual generation of aphids within one species, using light and fluorescent microscopy, as well as transmission and scanning electron microscopy. The results revealed that males have testes composed of three follicles fused by the upper ends of the vasa efferentia, the vasa deferentia run independently, the accessory glands are asymmetric and the ejaculatory duct shortened. Oviparous females have ovaries composed of seven ovarioles each. The lateral oviducts join to a short common oviduct connected with the unpaired spermatheca and paired accessory glands. Yolky eggs with an aggregation of symbiotic bacteria at the posterior pole are produced. Histologically, the components of genital tracts are broadly similar: the epithelial cells of the walls of the vasa deferentia and accessory glands of the male and oviparous female have secretory functions which correlate with the age of the studied morphs. We also found symbiotic bacteria within the vasa deferentia epithelial cells in males and within the cells of the lateral oviducts of females. Because the pea aphid is listed among the 14 species that are of the greatest economic importance, our results will be useful for managing aphid populations, protecting plants and ensuring global food security.