Sexual Generation Research Articles

Faithful vertical transmission but ineffective horizontal transmission of bacterial endosymbionts during sexual reproduction of the black bean aphid, Aphis fabae

1. Insects are commonly infected with bacterial endosymbionts. In addition to the costs and benefits associated with harbouring these symbionts, their rates of vertical and horizontal transmission are important determinants of symbiont prevalence.2. Aphids are cyclical parthenogens and show virtually perfect maternal transmission of endosymbionts during asexual reproduction. Less clear is the role of the annual sexual generation, during which overwintering eggs are produced. Data from pea aphids (Acyrthosiphon pisum Harris) suggest that maternal transmission failures and horizontal transmission via males may occur under sexual reproduction at least occasionally. No such data exist for other aphid species.3. In the present study, the rates of maternal and paternal transmission of facultative endosymbionts during sexual reproduction in the black bean aphid, Aphis fabae (Scopoli) were examined. Crosses were performed between clones infected with Hamiltonella defensa, clones infected with Regiella insecticola and clones without facultative endosymbionts, and eggs were overwintered under three different conditions.4. Only one of 205 offspring from crosses testing for maternal transmission failed to inherit the symbiont present in the maternal clone, and in crosses testing for horizontal transmission, only one of 412 offspring acquired a facultative symbiont from the father.5. These results show that in A. fabae, maternal transmission of H. defensa and R. insecticola is extremely reliable also during sexual reproduction, indicating that maternal transmission failures are unlikely to exert a significant influence on frequencies of infection in the field. Paternal transmission of endosymbionts was exceedingly rare, suggesting that this route of horizontal transmission may be less important than hitherto assumed.

"Eternal, Slithery Penance": Graham Swift's Waterland and the Secularization of Confession

"Eternal, Slithery Penance":Graham Swift's Waterland and the Secularization of Confession Ryan Siemers (bio) "Your history teacher wishes to give you the complete and final version," the narrator of Graham Swift's Waterland, Tom Crick, tells his high school students (7–8). Crick refers to his personal and family history, his account of which constitutes the novel. Crick's avowed aim echoes auricular confession, which requires the complete recounting of a penitent's sins before he or she receives absolution. Like a religious confessant, Crick seeks absolution for past sins: he feels guilty about the abortion of his would-be son, the death of his childhood friend Freddie Parr, and the suicide of his brother. Indeed, Crick reveals his guilt over these deaths to the police: "I confess my responsibility, jointly with my wife, for the death of three people" (314).1 However, because he speaks to his students, to the police, and (implicitly) to the reader rather than to a father confessor with the purpose and authority to offer him absolution, Crick's secular self-examination and self-narration threaten to be endless. In a desperate and improvisational response to that problem, Crick universalizes his condition over the course of his narrative to assuage his feelings of guilt and bring his secular confession to a close. Crick's narrative should be read in the context of—and as a response to the problems posed by—the secularization of confession. As I use the term here, "secularization" stands not for an inevitable decline of religious affiliation due to modernization (a once-prominent thesis that has undergone revision in sociology), but for an interminable historical [End Page 56] process by which religious concepts and practices are translated or transposed into the secular sphere and by which they continue to function in that sphere, often with unexpected consequences.2 Carl Schmitt and Karl Löwith provide examples of secularization understood as transposition: Schmitt claims that "all significant concepts of the modern theory of the state are secularized theological concepts" (37), and Löwith argues that the modern notion of progress and the associated conception of linear history are due to the secularization of Christian eschatology. As I use it here, secularization encompasses the kind of transposition proposed by Schmitt and Löwith, along with the continuing and unpredictable dynamism of once-religious contents following that transposition. Max Weber's analysis may provide an example of the latter: for Weber, the transposition of rational acquisitiveness from Protestantism (wherein wealth provides evidence of election) to modern capitalism (wherein wealth is an end in itself) conditions the modern laborer and makes the current economic order possible—which, of course, is not at all what Martin Luther or John Calvin had in mind. Waterland's Tom Crick demonstrates the transposition of religious contents into the secular sphere, but his narrative also suggests that Weber's rationalization may reverse itself, that disenchantment may prompt re-enchantment. Crick transposes auricular confession into the relationship between himself and his students, but he then appeals to an enchanted circular history as a means to escape the psychological impasse produced by that transposition. Crick critiques progress and prefers cyclical history. Like Löwith, who opts for circular history because it comports with the notion of historical continuity (207), Crick desires historical continuity—especially regarding sexual generation, which in his case has been stymied. (His wife, Mary, is unable to bear children following an abortion.) More importantly, Crick prefers a re-enchanted form of that history—re-enchanted not by a return to ancient Greek paganism, as Löwith ultimately proposes, but through an idiosyncratic mythology of Crick's own making—because it assuages his sense of guilt by relating his individual experience to a universal pattern. Waterland thus illuminates a psychological dimension of Löwith's preferred alternative to linear history: for a subject suffering from a guilty conscience, circular history transforms personal guilt into a universal condition that is less psychologically burdensome due to its impersonality. [End Page 57] Before we examine Crick's narrative in more detail, however, we should address an important objection to the basic premise that secularization entails the transposition of religious concepts and practices...

Transcriptome profiling of Symbion pandora (phylum Cycliophora): insights from a differential gene expression analysis

Cycliophorans are characterized by a complex life cycle that involves an asexual generation and a sexual generation. The most prominent life cycle stage in both generations is the so-called feeding stage. Using RNA-Seq, we profiled differential gene expression between feeding stages from asexual and sexual generations to study this intergenerational shift. For this, we also generated a reference transcriptome for the cycliophoran Symbion pandora. We found that a total of 2660 contigs (more than 10% of the total transcriptome) correspond to genes that are expressed differentially in the feeding stages from the asexual generation as compared to the sexual feeding stages. Among these, 1236 genes are upregulated in the asexual stages as compared to the sexual stages. Conversely, 1424 genes are upregulated in the sexual stages as compared to the asexual stages. The asexual stages express genes predominantly related to RNA processing and splicing as well as protein folding, which suggests a high degree of regulation at the transcriptional and post-transcriptional levels. In marked contrast, the sexual stages highly express genes related to signal transduction and neurotransmission. This is the first time that a large whole-transcriptome RNA-Seq expression dataset has been generated for any cycliophoran. Moreover, this study provides important information for further studies on the molecular mechanisms that are involved in the shift from asexual to sexual generations in this still enigmatic group.

Stress-induced memory alters growth of clonal offspring of white clover (Trifolium repens).

The phenotype of an individual can be modified by the environment experienced by its predecessors, a phenomenon called transgenerational or maternal effects. These effects are studied mostly across sexual generations and are thought to be mediated also by epigenetic variation. However, we do not know how important transgenerational effects are across asexual generations of clonal plants. We investigated the role of different drought intensities and durations experienced by parental plants of Trifolium repens on the growth of offspring ramets after transplantation of clonal cuttings to control conditions. We also treated half of the plants with 5-azacytidine, which is a demethylating agent, to test the potential role of DNA methylation on transgenerational effects. Transgenerational effects were manifested as increased biomass of offspring ramets if parental plants experienced medium drought applied for a short period and decreased biomass of offspring ramets if parental plants experienced intense drought for a short period. These transgenerational effects were not observed for offspring of parents from the same treatments if these were treated with 5-azacytidine, whose application significantly decreased the amount of 5-methyl-2'-deoxycytidine in plants. Transgenerational effects might play an important role in the clonal plant Trifolium repens and are probably mediated by epigenetic variation. The growth and behavior of clonal plants might be affected not only by the ambient environment but also by environments that are no longer present at the time of clonal reproduction. This phenomenon can have yet unacknowledged ecological and evolutionary implications for clonal plants.

First Description of Asexual Generation and Taxonomic Revision of the Gall Wasp GenusLatuspina(Hymenoptera: Cynipidae: Cynipini)

The asexual generation of Latuspina Monzen is described for the first time. Although this genus was established based only on sexual generation upon which females possess a trifurcate hypopygial spine, the asexual generation females of Latuspina , including the type species L. stirps , possess a needle-shaped hypopygial spine, similar to that of many Cynipini, oak gall wasps. Based on the trifurcate hypopygial spine in sexual generation females, Neuroterus atamiensis Ashmead, N. hellwegi Dettmer, and N. nawai Ashmead are transferred to Latuspina in this paper: L. atamiensis comb. nov. , L. hellwegi comb. nov. , and L. nawai comb. nov. In addition, L. kofuensis Ide et Abe sp. nov. and L. abemakiphila Ide et Abe sp. nov. are described as new species from Japan. Latuspina includes nine species in total, but the asexual generation galls and adults of the following four species are unknown: L. abemakiphila , the Taiwanese species L. manmiaoyangae Melika et Tang, and two mainland Chinese species L. acutissimae Wang, Pujade-Villar et Guo and L. shaanxinensis Wang, Pujade-Villar et Guo. Although the host plant of L. shaanxinensis was reported as genus “ Quercus ” without specific name, the other species of Latuspina induce galls on oaks of the section Cerris of the genus Quercus , implying that they are specialized to oaks of this section.

Chromosome fusions triggered by noncoding RNA

ABSTRACTChromosomal fusions are common in normal and cancer cells and can produce aberrant gene products that promote transformation. The mechanisms driving these fusions are poorly understood, but recurrent fusions are widespread. This suggests an underlying mechanism, and some authors have proposed a possible role for RNA in this process. The unicellular eukaryote Oxytricha trifallax displays an exorbitant capacity for natural genome editing, when it rewrites its germline genome to form a somatic epigenome. This developmental process provides a powerful model system to directly test the influence of small noncoding RNAs on chromosome fusion events during somatic differentiation. Here we show that small RNAs are capable of inducing chromosome fusions in 4 distinct cases (out of 4 tested), including one fusion of 3 chromosomes. We further show that these RNA-mediated chromosome fusions are heritable over multiple sexual generations and that transmission of the acquired fusion is associated with endogenous production of novel piRNA molecules that target the fused junction. We also demonstrate the capacity of a long noncoding RNA (lncRNA) to induce chromosome fusion of 2 distal germline loci. These results underscore the ability of short-lived, aberrant RNAs to act as drivers of chromosome fusion events that can be stably transmitted to future generations.

The role of transgenerational effects in adaptation of clonal offspring of white clover (Trifolium repens) to drought and herbivory

Environmentally induced transgenerational effects can increase success of offspring and thereby be adaptive if offspring experience conditions similar to the parental environment. The ecological and evolutionary significance of these effects in plants have been considered overwhelmingly in the context of sexual generations. We investigated whether drought stress and jasmonic acid, a key hormone involved in induction of plant defenses against herbivores, applied in the parental generation, trigger transgenerational effects in clonal offspring of Trifolium repens and whether these effects are adaptive. We found that drought stress experienced by parents significantly affected phenotypes of offspring ramets. Offspring ramets were bigger if they were produced in the parental water regime (control/drought). Repeated application of jasmonic acid to parents increased the subsequent growth of offspring ramets produced by stolons after they were disconnected from the parental clone. However, these offspring ramets experienced similar herbivory by the generalist Spodoptera littoralis caterpillar as did control offspring ramets, indicating that this jasmonic acid application in the parental generation did not result in a transgenerational effect comprising increased herbivory resistance. We conclude that, overall, environmental interaction in the parental generation can trigger transgenerational effects in clonal plants and some of these effects can be adaptive. Moreover, transgenerational effects in clonal plants that significantly influence their growth and behavior can ultimately affect the evolutionary trajectories of clonal populations.

Taxonomical implications of the comparative study of the genus Drepanosiphum Koch, 1855 (Hemiptera: Aphididae, Drepanosiphinae)

The aim of the study was to review the sexual generation of the species of the aphid genus Drepanosiphum Koch. Oviparous females and males of Drepanosiphum iranicum Hille Ris Lambers are described and illustrated in detail. The poorly known sexuales of D. acerinum (Walker), D. aceris Koch, D. braggii Gillette, D. dixoni HRL, D. oregonensis Granovsky and D. platanoidis (Schrank) are re-described and illustrated in detail. Biometric data for the oviparous females and males are reported and keys for the sexual generation of the species that were studied are provided for the first time. The status of the closely related species D. acerinum and D. caucasicum as well as D. platanoidis and D. iranicum is discussed. The newly recognised species D. latifemorum sp. n., which is closely related to D. oregonensis, is described. Blackman and Eastop’s general key to the species that are associated with Acer spp. is modified to include the new species. The most significant diagnostic characters of winged viviparous females of all of the known Drepanosiphum species are also provided and illustrated.

Description of the sexual generation of Trichagalma acutissimae (Hymenoptera: Cynipidae) and notes on its heterogonic life cycle

The adults and galls of the sexual generation of the oak gall wasp Trichagalma acutissimae (Monzen, 1956) (Hymenoptera: Cynipidae) (=T. glabrosa Pujade-Villar n. syn.) are described for the first time. The heterogonic life cycle of T. acutissimae has been established experimentally in a field trial. We also provide information on the taxonomy, biology and host plant. A key to species of Trichagalma including both sexual and asexual generation is given.

Abstract A1-28: Chromosome fusions triggered by noncoding RNA

Abstract Chromosomal fusion is a frequent occurrence in cancer cells and can promote transformation through the generation of oncogenic gene products. There are two non-exclusive models for how these chromosome fusions may occur: (1) the instability of the cancer genome produces chromosomal fusions randomly and those promoting transformation enjoy a selective advantage, or (2) some non-random mechanism drives chromosome fusion. Evidence for (2) comes from recurrent fusion events and correlative human data linking noncoding RNA expression with chromosome fusion. To help address this important fundamental question, we functionally tested the role of noncoding RNA, specifically piRNAs, in promoting chromosomal fusion in the ciliate, Oxytricha trifallax, a microbial eukaryote. We microinjected custom piRNAs into cells and observed chromosome fusion in four cases (of four tested), including a double fusion event and a chromosome circularization event (self-fusion). Furthermore, these RNA-mediated inter-and-intra-chromosomal fusions are heritable over multiple sexual generations, illustrating the ability of noncoding RNAs to program genome architecture, including chromosome fusion and circularization. Citation Format: John Bracht, Xing Wang, Keerthi Shetty, Xiao Chen, Mariusz Nowacki, Sierra McCloud, Derek Clay, Laura Landweber. Chromosome fusions triggered by noncoding RNA. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A1-28.

Parasitoids, Hyperparasitoids, and Inquilines Associated With the Sexual and Asexual Generations of the Gall Former,Belonocnema treatae(Hymenoptera: Cynipidae)

Insect-induced plant galls are thought to provide gall-forming insects protection from predation and parasitism, yet many gall formers experience high levels of mortality inflicted by a species-rich community of insect natural enemies. Many gall-forming cynipid wasp species also display heterogony, wherein sexual (gamic) and asexual (agamic) generations may form galls on different plant tissues or plant species. Despite broad interest in using these systems to study parasitism, enemy escape, and community assembly, few studies have provided complete characterizations of the natural enemy diversity associated with gall-forming wasp species, and fewer still have done so for both alternating generations. Here, we characterize the parasitoids, inquilines, and hyperparasitoids associated with the alternating sexual and asexual generations of the cynipid gall former, Belonocnema treatae Mayr in Texas, USA . We find 24 species associated with the asexual generation in leaf galls and four species associated with the sexual generation in root galls. We provide photographs and mitochondrial sequences for most species, discuss implications of these findings for hypotheses that consider heterogony as an adaptation for escape from natural enemies, and contemplate the relative incidence of specialized versus generalist feeding habits among gall former natural enemies.

Modeling the potential distribution and conservation status of three species of oak gall wasps (Hymenoptera: Cynipidae) in the Iberian range

Cynipids (Hymenoptera: Cynipidae) induce a wide variety of complex galls on plants of different botanical families, particularly on Quercus species. Cynipid galls are well known to host large communities of insects, providing fundamental ecological niches for different animal taxa, which are organized in structured and relatively isolated communities at the microhabitat level. Gall communities of Quercus woodlands could be a conservation concern considering some risks, which affect several species of the Parasitica group of Hymenoptera, within which gall wasps and their parasitoids and inquilines are included. These risks concerning Parasitica species are mainly due to three causes: their high trophic level, high host specialization and the lack of knowledge of their biology. In this paper, a preliminary approach to this issue is presented for the Iberian–Balearic range. We model and study the ecological niche of three cynipid gall species that induce galls on Quercus species (Andricus quercustozae, Biorhiza pallida and Plagiotrochus quercusilicis). The cynipid gall species were selected for their different sets of host species and life cycle. The Ecological Niche Factor Analysis and two niche models built for each species (MAXENT and Mahalanobis Distances) support the interpretation that the bioclimatic variables considered have effects on cynipids through their respective sets of host plants. In addition, the results regarding A. quercustozae are consistent with the hypothetical existence of cryptic sexual generation (exposed in other works) parasitizing cork oak (Quercus suber), which could have another key role in its conservation.

Differential chromatin amplification and chromosome complements in the germline of Strongyloididae (Nematoda).

Nematodes of the genus Strongyloides are intestinal parasites of vertebrates including man. Currently, Strongyloides and its sister genus Parastrongyloides are being developed as models for translational and basic biological research. Strongyloides spp. alternate between parthenogenetic parasitic and single free-living sexual generations, with the latter giving rise to all female parasitic progeny. Parastrongyloides trichosuri always reproduces sexually and may form many consecutive free-living generations. Although the free-living adults of both these species share a superficial similarity in overall appearance when compared to Caenorhabditis elegans, there are dramatic differences between them, in particular with respect to the organization of the germline. Here we address two such differences, which have puzzled investigators for several generations. First, we characterize a population of non-dividing giant nuclei in the distal gonad, the region that in C. elegans is populated by mitotically dividing germline stem cells and early meiotic cells. We show that in these nuclei, autosomes are present in higher copy numbers than X chromosomes. Consistently, autosomal genes are expressed at higher levels than X chromosomal ones, suggesting that these worms use differential chromatin amplification for controlling gene expression. Second, we address the lack of males in the progeny of free-living Strongyloides spp. We find that male-determining (nullo-X) sperm are present in P. trichosuri, a species known to produce male progeny, and absent in Strongyloides papillosus, which is consistent for a species that does not. Surprisingly, nullo-X sperm appears to be present in Strongyloides ratti, even though this species does not produce male progeny. This suggests that different species of Strongyloides employ various strategies to prevent the formation of males in the all-parasitic progeny of the free-living generation.

Chromosomes of Belonocnematreatae Mayr, 1881 (Hymenoptera, Cynipidae).

Chromosomes of the asexual and sexual generation of the gall wasp Belonocnema treatae Mayr, 1881 (Cynipidae) were analyzed. Females of both generations have 2n = 20, whereas males of the sexual generation have n = 10. Cyclical deuterotoky is therefore confirmed in this species. All chromosomes are acrocentric and form a continuous gradation in size. This karyotype structure is probably ancestral for many gall wasps and perhaps for the family Cynipidae in general. Chromosome no. 7 carries a characteristic achromatic gap that appears to represent a nucleolus organizing region.

Morphology of the European species of the aphid genus Eulachnus (Hemiptera: Aphididae: Lachninae) – A SEM comparative and integrative study

Scanning electron microscopy (SEM) methods were used for the first time to elucidate the external morphology of the European species of the genus Eulachnus (Hemiptera: Aphididae: Lachninae), a representative genus of the conifer-feeding aphids tribe Eulachnini. We examined and compared the external morphology of apterous and alate viviparous females from the parthenogenetic generation as well as oviparous females and alate males belonging to the sexual generation. FE-SEM images based on HMDS and cryo-SEM preparation techniques revealed better image quality than the CPD technique in regard to surface tension and morphological signs of cell deteriorations (i.e., existence of depressions, drying artifacts and membrane blebs). Three morphologically different species groups “agilis”, “brevipilosus” and “cembrae” were proposed due to the differences in head, antennae, legs and dorsal chaetotaxy as well as dorsal sclerotization. The most characteristic features and differences of representatives of these groups are presented and discussed.

Do all aphids benefit from climate warming? An effect of temperature increase on a native species of temperate climatic zone Cinara juniperi

Global warming has the potential to affect many animal species, in particular temperature-dependent insects with their short generation times and high reproductive rates which facilitate adaptations to long-term climatic fluctuations. Aphids are the model species in studying the association of insect biology with large-scale climate fluctuations because they multiply only within a certain range of temperatures and their rate of development directly depends on temperature. Here, we investigate the effect of climate warming on phenology and voltinism of the juniper aphid (Cinara juniperi De Geer 1773), a native species of a temperate climate zone in Poland. We also experimentally test for the temperature optimum of the study species. Our study demonstrated that environmental conditions significantly affected phenology of juniper aphid. The timing of larval emergence depended on mean temperatures in March, and in warmer years larvae appeared earlier. The emergence of the sexual generation was related to mean temperatures in August, and higher temperatures resulted in later sexual reproduction. Despite the elongation of the entire life cycle, by almost 3 months, we observed only one additional generation in warmer years. A possible explanation for this pattern may be that the increase in temperature recorded in recent years went beyond the temperature optimum of the study species. Our chamber experiment supports this assumption – juniper aphids developed faster and reproduced more effectively at 20 °C than at 25 °C.

A comparative morphometric study of the genus Drepanosiphoniella Davatchi, Hille Ris Lambers and Remaudière (Hemiptera: Aphididae: Drepanosiphinae)

The genus Drepanosiphoniella Davatchi, Hille Ris Lambers and Remaudière, 1957 of the subfamily Drepanosiphinae (Hemiptera: Aphididae) is revised using comparative morphology of parthenogenetic and sexual generations. On the basis of thorough examination of morphological characters, a full species status of Drepanosiphoniella fugans Remaudière and Leclant, 1972 stat. rev. is given, and supported by using statistical analysis – principal component analysis (PCA) and multiple discriminant analysis (canonical variates analysis). A new species, Drepanosiphoniella remaudièrei sp. n. Wieczorek, is described and figured in detail on the basis of specimens collected in Morocco. Fundatrix, oviparous female and apterous male of Drepanosiphoniella aceris aceris Davatchi, Hille Ris Lambers and Remaudière, 1957 are described and figured. Original keys to the identification of the known species and morphs of the genus Drepanosiphoniella as well as differences with related species are given. Notes about the distribution and host plants of the studied taxa are supplied. All species studied seem to be montane elements associated with Acer monspessulanum or its subspecies.

Giant females vs dwarfish males of the genus Stomaphis Walker (Hemiptera: Aphididae) - an aphid example of the ongoing course to permanent parthenogenesis?

The aim of the study is a review of the sexual generation of European species of the aphid genus Stomaphis Walker. Oviparous females and males of S. (Parastomaphis) longirostris and S. (Stomaphis) radicicola are described and figured in detail. Poorly known sexuales of S. (S.) bratislavensis, S. (S.) quercus, S. (S.) wojciechowskii, S. (P.) graffii, and S. (P.) juglandis are redescribed and figured in detail. Biometric data for the oviparous females and males are reported and keys for the sexual generation of the studied species are provided. On the basis of the morphological characters of the sexuales, supported by biological data, the taxonomic status of the subgenus Parastomaphis Pašek, 1953 stat. rev. is discussed. Aberrations of male morphology are presented, with reference to the general phenomenon of male morphology deterioration in the genus Stomaphis. The discussion also refers to the mating behavior and general evolutionary factors influencing the development of male dwarfism in Stomaphis.

دراسة مرجعية لمرض لفحة الأسكوكيتا على الحمص = A Review of Ascochyta Blight of Chickpea

This article aimed to present detailed literature review on chickpea Ascochyta blight disease. Ascochyta blight caused by Ascochyta rabiei is one of the most biotic stresses reducing chickpea yield. The fungus now exists in the most chickpea growing areas in the world. The most damaging symptoms are stem breakage and pod infection. The life cycle of the fungus consists of a single sexual generation (Didymella rabiei) per season which develops on infected plant debris during winter followed by several asexual generations during the growing season of the crop. The use of resistant cultivars is the most effective, economical and environmentally safe means to manage the disease. Other cultural practices, such as the use of disease free seeds or treated seeds, crop rotation for at least 4 years and deep ploughing of previous infested crop debris accompanied with spraying suitable fungicides in the correct times will minimize the disease severity.

Systematic position of Eulachnus cembrae Börner with description of hitherto unknown sexual morphs of E. pumilae Inouye (Hemiptera, Aphididae, Lachninae)

The identity of Eulachnus cembrae Borner, 1950, stat. rev. from Europe, treated as a synonym of E. pumilae Inouye, 1939 from East Asia is clarified based on characters of sexual morphs. The oviparous female and alate male forms of E. pumilae are described and figured in detail for the first time and the poorly known sexual forms of E. cembrae are redescribed and figured in detail as well. Sexual morphs of the two similar species are compared, and significant differences clearly distinguishing those species are presented. A key to the identification of oviparous females and males of E. cembrae and E. pumilae as well as notes on host plants and distribution of these species are provided. The status of E. pumilae in the European aphid-fauna is clarified. Morphological characters of the sexual generation that may be useful for species identification are discussed.