Gall Aphid Research Articles

The lost generation of Pemphigus populiglobuli (Hemiptera, Aphididae): exploring the taxonomy of the Svalbard aphids of genus Pemphigus

Species identification within the aphid genus Pemphigus Hartig, 1839 poses challenges due to morphological similarities and host-plant associations. Aphids of this genus generally exhibit complex life cycles involving primary hosts (poplars) and secondary (mostly unrelated herbaceous) host-plants, with some species relying solely on root-feeding generation. An example is a representative of the genus Pemphigus, trophically associated with grass roots, found in the High Arctic Svalbard archipelago. Historical records tentatively identify it as Pemphigus groenlandicus (Rübsaamen, 1898), although its formal classification remains elusive, due to limited material of freshly collected samples. Recent collections from 2007 to 2024 across various Svalbard sites, revealed its presence under stones in sheltered microhabitats, providing valuable specimens for comparative studies. Our molecular analyses indicate that the Svalbard specimens are not a separate species commonly identified as P. groenlandicus, nor an anholocyclic generation of Pemphigus bursarius (Linnaeus, 1758) or P. borealis Tullgren, 1909, but represent a secondary generation of Pemphigus populiglobuli Fitch, 1859, the Nearctic poplar bullet gall aphid. This suggests that they may have lost their primary host associations and adapted to living on grass roots year-round. Our specimens did not host any known facultative symbionts; however, we detected a strain of Pseudomonas Migula, 1894, closely related to a cold-tolerant bacterium abundant in polar regions. The present study also investigates the taxonomic relationships and morphometric characteristics of grass-feeding Pemphigus populations across the Arctic and an isolated locations on the European continent. Specimens from Svalbard were compared with samples from Greenland and Iceland, but identified no substantial morphometric differences among these geographically separated populations. Similarly, analyses of samples of Pemphigus groenlandicus crassicornis Hille Ris Lambers, 1952 from Sweden and Spain reveals a high morphometric similarity to the Arctic population, indicating a strong link between these traits and geographical variability. Despite the limitations in fresh material availability across locations, minor morphometric variations and shared ecological niches (all populations studied inhabiting grass roots, a unique trait within the Pemphigus genus) suggest treating both P. groenlandicus and its subspecies crassicornis as a junior synonym to P. populiglobuli. The study also demonstrates that the secondary generation of P. populiglobuli is a terrestrial microarthropod that overwinters in a postembryonic life-stage in situ in soil and vegetation under harsh Arctic conditions, and its cryptic life complicates its distribution mapping.

Study of Altenia wagneriella (rebel) as a predator associated with Forda marginata from Iran.

The larvae of Altenia spp. and gall aphids are known to feed on plants related to Anacardiaceae. This study documents the aphidophagous habit of Altenia wagneriella, which was verified by molecular techniques, subsequently by the gut dissection test, and direct observation. To identify the moth larvae and adult aphids, two mitochondrial genes, cytochrome c oxidase I (COI) and cytochrome b (Cytb), were amplified by polymerase chain reaction (PCR). Nested PCR with the aphid-specific primer pairs AphidF and AphidR was used to detect aphids in the body of moth larvae. The specificity of the primers was verified by PCR analysis of DNA from moth larvae and adult aphids. The method detected aphids in moth larvae, and a band of approximately 200bp was amplified from moth larvae feeding on aphids. No cross reactions with moth larvae were observed. In the laboratory, all moth larvae feeding on aphids (Forda marginata) were also PCR positive for aphids. Gall-inducing insects are microhabitat engineers that manipulate their host to obtain a better nutrient supply, as well as protection from natural enemies and abiotic factors. This is the first recorded instance worldwide of the carnivorous larva of the moth A. wagneriella acting as an aphid predator, as well as the first record of a host insect for this species. Additionally, it is the first effort to molecularly analyze the predator-prey relationship between the moth larvae and the aphids inside the wild pistachio gall.

Communal behavior and its exploitation in Tamalia social gall aphids (Aphididae: Tamaliinae)

Communal behavior and its exploitation in Tamalia social gall aphids (Aphididae: Tamaliinae)

Comparative genomics of the primary endosymbiont Buchnera aphidicola in aphid hosts and their coevolutionary relationships

BackgroundCoevolution between modern aphids and their primary obligate, bacterial endosymbiont, Buchnera aphidicola, has been previously reported at different classification levels based on molecular phylogenetic analyses. However, the Buchnera genome remains poorly understood within the Rhus gall aphids.ResultsWe assembled the complete genome of the endosymbiont Buchnera in 16 aphid samples, representing 13 species in all six genera of Rhus gall aphids by shotgun genome skimming method. We compared the newly assembled genomes with those from GenBank to comprehensively investigate patterns of coevolution between the bacteria Buchnera and their aphid hosts. Buchnera genomes were mostly collinear, and the pan-genome contained 684 genes, in which the core genome contained 256 genes with some lineages having large numbers of tandem gene duplications. There has been substantial gene-loss in each Buchnera lineage. We also reconstructed the phylogeny for Buchnera and their host aphids, respectively, using 72 complete genomes of Buchnera, along with the complete mitochondrial genomes and three nuclear genes of 31 corresponding host aphid accessions. The cophylogenetic test demonstrated significant coevolution between these two partner groups at individual, species, generic, and tribal levels.ConclusionsBuchnera exhibits very high levels of genomic sequence divergence but relative stability in gene order. The relationship between the symbionts Buchnera and its aphid hosts shows a significant coevolutionary pattern and supports complexity of the obligate symbiotic relationship.

Complete Mitochondrial Genome and Phylogenetic Position of Nurudea zhengii Ren (Insecta, Hemiptera, Aphididae).

Nurudea zhengii Ren was identified by aphid morphological characteristics as well as the gall shape and host plant species, and placed in the tribe Fordini (Hemiptera, Aphididae, Eriosomatinae). Here, its whole genome was firstly sequenced by a genome-skimming method and its mitochondrial genome (mitogenome) was assembled to examine its genetic variation and phylogenetic position. The complete mitogenome of Nurudea zhengii is 15,392bp in length, and consists of 13 protein-coding genes, 22 tRNAs, two rRNAs and one D-loop region. The gene order follows the mitogenomes of the other Rhus gall aphids, and similarly has an AT bias with the content of 83.9%. The majority strand is A-skewed and C-skewed, and shows opposite skewness for G-skewed in the minority strands. The ratios of nonsynonymous to synonymous substitution rates of protein-coding genes are lower than one except for ATP8, which indicated that ATP8 was undergoing positive selection. Phylogenetic analysis among the Rhus gall aphids based on 13 protein-coding genes and two rRNA genes showed that N. zhengii was sister to N. shiraii, and then clustered with N. yanoniella as a group with high support value. The two species, N. shiraii and N. yanoniella, share the same host plant Rhus chinensis, while the host of N. zhengii is R. hypoleuca. However, the phylogenetic relationship indicated that the taxa sharing the same host plant were not absolutely clustered as the closest taxa at least at species level.

A chromosome-scale genome of Rhus chinensis Mill. provides new insights into plant-insect interaction and gallotannins biosynthesis.

Rhus chinensis Mill., an economically valuable Anacardiaceae species, is parasitized by the galling aphid Schlechtendalia chinensis, resulting in the formation of the Chinese gallnut (CG). Here, we report a chromosomal-level genome assembly of R. chinensis, with a total size of 389.40 Mb and scaffold N50 of 23.02 Mb. Comparative genomic and transcriptome analysis revealed that the enhanced structure of CG and nutritional metabolism contribute to improving the adaptability of R. chinensis to S. chinensis by supporting CG and galling aphid growth. CG was observed to be abundant in hydrolysable tannins (HT), particularly gallotannin and its isomers. Tandem repeat clusters of dehydroquinate dehydratase/shikimate dehydrogenase (DQD/SDH) and serine carboxypeptidase-like (SCPL) and their homologs involved in HT production were determined as specific to HT-rich species. The functional differentiation of DQD/SDH tandem duplicate genes and the significant contraction in the phenylalanine ammonia-lyase (PAL) gene family contributed to the accumulation of gallic acid and HT while minimizing the production of shikimic acid, flavonoids, and condensed tannins in CG. Furthermore, we identified one UDP glucosyltransferase (UGT84A), three carboxylesterase (CXE), and six SCPL genes from conserved tandem repeat clusters that are involved in gallotannin biosynthesis and hydrolysis in CG. We then constructed a regulatory network of these genes based on co-expression and transcription factor motif analysis. Our findings provide a genomic resource for the exploration of the underlying mechanisms of plant-galling insect interaction and highlight the importance of the functional divergence of tandem duplicate genes in the accumulation of secondary metabolites.

A chromosome-level genome assembly of the Rhus gall aphid Schlechtendalia chinensis provides insight into the endogenization of Parvovirus-like DNA sequences

The Rhus gall aphid, Schlechtendalia chinensis, feeds on its primary host plant Rhus chinensis to induce galls, which have economic importance in medicines and the food industry. Rhus gall aphids have a unique life cycle and are economically beneficial but there is huge gap in genomic information about this group of aphids. Schlechtendalia chinensis induces rich-tannin galls on its host plant and is emerging as a model organism for both commercial applications and applied research in the context of gall production by insects. Here, we generated a high-quality chromosome-level assembly for the S. chinensis genome, enabling the comparison between S. chinensis and non-galling aphids. The final genome assembly is 344.59 Mb with 91.71% of the assembled sequences anchored into 13 chromosomes. We predicted 15,013 genes, of which 14,582 (97.13%) coding genes were annotated, and 99% of the predicted genes were anchored to the 13 chromosomes. This assembly reveals the endogenization of parvovirus-related DNA sequences (PRDs) in the S. chinensis genome, which could play a role in environmental adaptations. We demonstrated the characterization and classification of cytochrome P450s in the genome assembly, which are functionally crucial for sap-feeding insects and have roles in detoxification and insecticide resistance. This genome assembly also revealed the whole genome duplication events in S. chinensis, which can be considered in comparative evolutionary analysis. Our work represents a reference genome for gall-forming aphids that could be used for comparative genomic studies between galling and non-galling aphids and provides the first insight into the endogenization of PRDs in the genome of galling aphids. It also provides novel genetic information for future research on gall-formation and insect-plant interactions.

The Economic Importance of Insects: A Comprehensive Review

Insects are regarded as the largest group of arthropods on earth. They are easy to breed and have a large population due to their high fecundity and species diversity. Though a lot of people are aware of honey and silk as products from beneficial insects, many people are also unaware of other products like wax, Lac, gall aphid and their uses. Insect breeding and their industrial uses have attracted much attention in different countries across the world. Insects are often reared for the biological control of agricultural and sanitary pests. Some other insects serve as chemical raw materials for industries. In agriculture, insects are used as pollinators and to increase the yield of crops Scorpion venom and oily substances from blister beetles and other insects are used as medicine. In this comprehensive review article, we have fully examined the use of insects in the industry.

Comparative genetic diversity and structure of Rhus gall aphid Schlechtendalia chinensis and its host plant Rhus chinensis

Comparative genetic diversity and structure of Rhus gall aphid Schlechtendalia chinensis and its host plant Rhus chinensis

Genome-wide identification and characterization of the chemosensory relative protein genes in Rhus gall aphid Schlechtendalia chinensis

BackgroundThe Rhus gall aphid Schlechtendalia chinensis specially uses the only species Rhus chinensis and certain moss species (Mniaceae) as its primary host plant and secondary host plants, respectively. Rhus galls are formed on the primary host by the sucking of aphids, and used in traditional medicine as well as other various areas due to their high tannin contents. Chemoreception is critical for insect behaviors such as host searching, location and identification of mates and reproductive behavior. The process of chemoreception is mediated by a series of protein gene families, including odorant-binding proteins (OBPs), chemosensory proteins (CSPs), olfactory receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), and sensory neuron membrane proteins (SNMPs). However, there have been no reports on the analysis of molecular components related to the chemoreception system of S. chinensis at the genome level.ResultsWe examined the genes of eight OBPs, nine CSPs, 24 ORs, 16 GRs, 22 IRs, and five SNMPs in the S. chinensis genome using homological searches, and these chemosensory genes appeared mostly on chromosome 1. Phylogenetic and gene number analysis revealed that the gene families, e.g., ORs, GRs, CSPs and SNMPs in S. chinensis, have experienced major contractions by comparing to Myzus persicae, while the two gene families OBPs and IRs had slight expansion. The current results might be related to the broader host range of M. persicae versus the specialization of S. chinensis on only a host plant. There were 28 gene pairs between genomes of S. chinensis and Acyrthosiphon pisum in the chemoreceptor gene families by collinear comparison. Ka/Ks ratios (< 1) indicated that the genes of S. chinensis were mainly affected by purification selection during evolution. We also found the lower number and expression level of chemoreception genes in S. chinensis than in other 11 aphid species, such as ORs, GRs and IRs, which play an important role in host search.ConclusionOur study firstly identified the genes of the different chemosensory protein gene families in the S. chinensis genome, and analyzed their general features and expression profile, demonstrating the importance of chemoreception in the aphid and providing new information for further functional research.

Candidate genes potentially involved in molting and body size reduction in the male of the horned gall aphid, Schlechtendalia chinensis.

In general, insects grow (increase in body size) through molting. To the opposite, the body size of the males of the horned gall aphid, Schlechtendalia chinensis, gets smaller after molting and as they age. To understand the molecular bases of this rare phenomenon, transcriptomes were generated from 1-5days old male and the data were analyzed via a weighted gene co-expression network analysis (WGCNA). A total of 15 partitioned modules with different topological overlaps were obtained, and four modules were identified as highly significant for male body length (p < 0.05). Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis suggested that a portion of genes in the four modules are likely involved in autophagy and apoptosis. In addition, a total of 40 hub genes were obtained in the four modules, and among them eight genes were highly expressed in males compared to individuals of other generations of S. chinensis. These eight genes were associated with autophagy and apoptosis. Our results reveal the unique negative growth phenomenon in male S. chinensis after molting, and also suggest that the male S. chinensis with no ability to feed probably decompose their own substances via autophagy and apoptosis to provide energy for life activities such as germ cell development.

Mobilome of the Rhus Gall Aphid Schlechtendalia chinensis Provides Insight into TE Insertion-Related Inactivation of Functional Genes.

Transposable elements (TEs) comprise a considerable proportion of insect genomic DNA; how they contribute to genome structure and organization is still poorly understood. Here, we present an analysis of the TE repertoire in the chromosome-level genome assembly of Rhus gall aphid Schlechtendalia chinensis. The TE fractions are composed of at least 32 different superfamilies and many TEs from different families were transcriptionally active in the S. chinensis genome. Furthermore, different types of transposase-derived proteins were also found in the S. chinensis genome. We also provide insight into the TEs related insertional inactivation, and exogenization of TEs in functional genes. We considered that the presence of TE fragments in the introns of functional genes could impact the activity of functional genes, and a large number of TE fragments in introns could lead to the indirect inactivation of functional genes. The present study will be beneficial in understanding the role and impact of TEs in genomic evolution of their hosts.

Detoxification Gene Families at the Genome-Wide Level of Rhus Gall Aphid Schlechtendalia chinensis.

The Rhus gall aphid Schlechtendalia chinensis uses the species Rhus chinensis as its primary host plant, on which galls are produced. The galls have medicinal properties and can be used in various situations due to their high tannin content. Detoxification enzymes play significant roles in the insect lifecycle. In this study, we focused on five detoxification gene families, i.e., glutathione-S-transferase (GST), ABC transporter (ABC), Carboxylesterase (CCE), cyto-chrome P450 (CYP), and UDP-glycosyltransferase (UDP), and manually annotated 144 detoxification genes of S. chinensis using genome-wide techniques. The detoxification genes appeared mostly on chromosome 1, where a total of two pair genes were identified to show tandem duplications. There were 38 gene pairs between genomes of S. chinensis and Acyrthosiphon pisum in the detoxification gene families by collinear comparison. Ka/Ks ratios showed that detoxification genes of S. chinensis were mainly affected by purification selection during evolution. The gene expression numbers of P450s and ABCs by transcriptome sequencing data were greater, while gene expression of CCEs was the highest, suggesting they might be important in the detoxification process. Our study has firstly identified the genes of the different detoxification gene families in the S. chinensis genome, and then analyzed their general features and expression, demonstrating the importance of the detoxification genes in the aphid and providing new information for further research.

Closing the Gap: Horizontal Transfer of Mariner Transposons between Rhus Gall Aphids and Other Insects.

Simple SummaryTransposable elements (TEs) are mobile genetic elements that invade and multiply in host genomes. Besides vertical inheritance, it can transfer from one species to another through a phenomenon called horizontal transfer (HT). HT is crucial for TEs survival in genomes but also a significant disadvantage for host genomes, and recurrent HTT events between different hosts could shape and affect their genome architecture. HTT could be harmful to host genomes, but sometimes it can be useful and may play a role in the adaptive evolution of the host genome. HTT is well reported in many eukaryotes; however, there is still a considerable gap of knowledge about HTT in some organisms. This study closed the knowledge gap about HTT regarding Rhus gall aphids and reported multiple events of HTT involving Rhus gall aphids and other insects.Horizontal transfer of transposons (HTT) is an essential source of genomic evolution in eukaryotes. The HTT dynamics are well characterized in eukaryotes, including insects; however, there is a considerable gap in knowledge about HTT regarding many eukaryotes’ species. In this study, we analyzed the events of the HTT between Rhus gall aphids (Hemiptera) and other insects. We analyzed the Mariner-like transposable elements (MLEs) belonging to Rhus gall aphids for the possible HT events. The MLEs have a patchy distribution and high similarity over the entire element length with insect MLEs from different orders. We selected representative sequences from the Rhus gall MLEs and identified five events of HT between MLEs of Rhus gall aphids and other insects from five different orders. We also found multiple HTT events among the MLEs of insects from the five orders, demonstrating that these Mariner elements have been involved in recurrent HT between Rhus gall aphids and other insects. Our current study closed the knowledge gap surrounding HTT and reported the events between Rhus gall aphids and other insects for the first time. We believe that this study about HTT events will help us understand the evolution and spread of transposable elements in the genomes of Rhus gall aphids.

Chromosome-level genome assembly for the horned-gall aphid provides insights into interactions between gall-making insect and its host plant.

The aphid Schlechtendalia chinensis is an economically important insect that can induce horned galls, which are valuable for the medicinal and chemical industries. Up to now, more than twenty aphid genomes have been reported. Most of the sequenced genomes are derived from free‐living aphids. Here, we generated a high‐quality genome assembly from a galling aphid. The final genome assembly is 271.52 Mb, representing one of the smallest sequenced genomes of aphids. The genome assembly is based on contig and scaffold N50 values of the genome sequence are 3.77 Mb and 20.41 Mb, respectively. Nine‐seven percent of the assembled sequences was anchored onto 13 chromosomes. Based on BUSCO analysis, the assembly involved 96.9% of conserved arthropod and 98.5% of the conserved Hemiptera single‐copy orthologous genes. A total of 14,089 protein‐coding genes were predicted. Phylogenetic analysis revealed that S. chinensis diverged from the common ancestor of Eriosoma lanigerum approximately 57 million years ago (MYA). In addition, 35 genes encoding salivary gland proteins showed differentially when S. chinensis forms a gall, suggesting they have potential roles in gall formation and plant defense suppression. Taken together, this high‐quality S. chinensis genome assembly and annotation provide a solid genetic foundation for future research to reveal the mechanism of gall formation and to explore the interaction between aphids and their host plants.

Insect industrialization and prospect in commerce: A case of China

AbstractInsects are the largest biological group on the earth, characterized by high biodiversity, easy rearing, and large populations. The utilization of insects in China has a long history and some insect species have contributed to the formation of characteristic industries. Insect products, such as silk and honey, are already familiar to the public; however, many beneficial insects and their products are not well known to most people, for example, lac insect and lac, gall aphid and Chinese gallnut, and insect wax. A new industry featuring the utilization and industrialization of insects has been rising in China. Chemically, insect products are used as raw materials; agriculturally, insects are utilized to pollinate crops for better yield; natural enemy insects have been reared to control pests; insect protein may be used for human food or animal feed; medicinally, chemical compounds may be extracted from insects as active ingredients for pharmaceutical usage; and ornamental butterfly has been applied in travel sightseeing. Insects' new purpose and function will be exploited as they gain recognition for their resources. This paper reviews insect industrialization in China and discusses the prospect of insect commerce in the future.

Comparative mitochondrial genomes of the Rhus gall aphid Kaburagia rhusicola subspecies with variable gall shapes

Rhus gall aphids (Hemiptera: Aphididae: Eriosomatinae) stimulate the formation of galls on their primary host plants (sumacs: Rhus spp., Anacardiaceae). The shapes of galls are often used as an extended phenotype to identify the aphid species and subspecies. We collected four Rhus galls with conspicuously different shapes formed by Kaburagia rhusicola aphids, whose sequences of the complete mitochondrial genomes (mitogenomes) were obtained by high-throughput sequencing. Each mitogenome was assembled into a circular molecule containing 13 protein-coding genes, two rRNAs, 22 tRNAs and one control region. All the protein-coding genes had a typical ATN initiation codon and TAA termination codon except for cox1 and nad4, which had a single T as stop codon. All the tRNAs could be folded as a typical clover-leaf secondary structure, except for trnS1 lacking a dihydrouridine (DHU) arm. The relative synonymous codon usage and ratio of nonsynonymous to synonymous substitution rates showed that the four K. rhusicola samples were highly similar to the subspecies K. r. ovogallis. The phylogenetic analyses grouped these samples with K. r. ovogallis in a clade sister to K. r. rhusicola. All these molecular analyses demonstrated that our current samples represented one subspecies of Kaburagia rhusicola, i.e., K. r. ovogallis, and the gall shape was variable even at the subspecies level in Kaburagia gall aphids.

Introduction of black currant under conditions of Novosibirsk region

Based on the study of 39 varieties of black currant on a complex of economically valuable features, conclusions were drawn: absolutely resistant varieties to spotted lesions were not revealed, all varieties are tolerant to septoriosis and anthracnose. Two varieties were affected by gall aphids: Minusinsk sweet and Bow Borisova (1 point). Altai early and Sweet-fruited were damaged by the kidney mite up to 30%. Varieties Mysterious, Belated, Compact have reached high overall productivity in the conditions of Novosibirsk region.

Characterization of Mariner transposons in seven species of Rhus gall aphids

Transposable elements (TEs), also known as jumping genes, are widely spread in the genomes of insects and play a considerable role in genomic evolution. Mariner/DD34D family belongs to class II transposable elements which is widely spread in the genomes of insects and have considerable role in genomic evolution. Mariner like elements (MLEs) were searched in the genomes of seven species of Rhus gall aphids belonging to six genera. In total, 121 MLEs were detected in the genomes of the seven investigated species of Rhus gall aphids, which showed a wide distribution in both close and distant related species. The sequences of MLEs ranged from 1 to 1.4 kb in length and the structural analysis of the MLEs showed that only five copies were potentially active with intact open reading frame (ORF) and terminal inverted repeats (TIRs). Phylogenetic analysis showed that all the 121 MLE sequences belonged to four subfamilies, i.e., Mauritiana, Drosophila, Vertumana and Irritans, among which Drosophila and Vertumana subfamilies were reported in aphids for the first time. Our present report revealed the diversity and distribution of MLEs in Rhus gall aphid genomes and expanded our understandings on the characterization of transposable elements in aphid genomes, which might be useful as genetic markers and tools and would play an important role in genomic evolution and adaptation of aphids.

Species of sucking pests of ornamental crops in the conditions of the Southern Coast of the Crimea

The results of the analysis of the species composition of sucking pests species during the period from 2009 to 2019 are presented. Based on long-term phytosanitary monitoring, 37 species belonging to 12 families were identified, of which the most numerous are the families Diaspididae and Aphididae of the order Hemiptera. According to the nature of trophic connections, 59.9% are monophages, 32.4% are polyphages and 8.1% are oligophages. According to the nature of the damage caused, sucking species differ from each other. Some species lead to a change in the color of leaves and flowers (thrips, mites, coccids), others cause deformation of the leaf blade and inflorescences (coccids, worms, false coccids, herbivorous mites) and the third group includes species that form galls on the leaves (laurel psyllid, pistachio marginal gall aphid). According to ecological features, sucking pest species are divided into three main groups: open-living species, which include aphids, cicadae, psyllas, white flies, the second group includes species that have covers of various nature on the body, such as coccids, worms and false coccids, and the third group consists of gall makers. The dominant species, the degree of harmfulness, the frequency of occurrence and the range of forage plants were determined.