Aphid Species Research Articles

Susceptibility of apple varieties to infestation by aphids (Hemiptera: Aphididae) in Southern Bulgaria

Aphids regularly infest apple orchards and are considered as one of the most damaging species, especially in humid conditions. In 2021-2023, the collection of different species and the rate of infestation by aphids on different apple varieties were studied in the region of Plovdiv, Bulgaria. Among the four aphid species identified in the apple orchard, Aphis spiraecola and Dysaphis plantaginea were predominant, followed by Aphis pomi and Dysaphis devecta. The rate of infestation varied significantly among the apple varieties. The Gala Resistant was the most infested by the aphids with a population coefficient (K) 302.5, followed by the Crimson Crisp – 124, the Pinova – 91, and the Red del Mestar – 52.5. The least infested variety was the Super Chief – 0.9, followed by the Modi – 2.2, the Fujion – 2.8, the Enterprise – 7.2 and the Rosella – 19. Keywords: apples, varietal susceptibility, aphids

First report of the giant conifer aphid, Cinara pinivora (Wilson) and the Monterey pine aphid, Essigella californica (Essig) (Hemiptera: Aphididae) in South Africa

Pine aphids represent a significant group of insect pests in coniferous ecosystems worldwide. To assess pine aphid prevalence and potentially new introductions in South Africa, aphid samples from various pine-growing regions were collected through national surveys conducted by the Tree Protection Co-operative Programme (TPCP) and directly sent from landowners to the FABI Diagnostic Clinic. Morphological examination and DNA barcoding confirmed two previously unreported aphid species as Cinara pinivora and Essigella californica. To our knowledge, this is the first report of these North American native aphids in South Africa. This study provides an important reference for future research aimed at safeguarding South Africa’s pine plantations against emerging threats from invasive aphid species.

Differential regulation of glucosinolate-myrosinase mediated defense determines host-aphid interaction in Indian mustard Brassica juncea L.

India's oilseed economy falls short of self-sufficiency and is supplemented by huge imports every year. Increasing national productivity of the major oilseeds is confronted with yield losses due to diverse biotic and abiotic stresses. The productivity of Indian mustard (Brassica juncea Linnaeus), belonging to the family Brassicaceae, is significantly reduced due to damage caused by mustard aphids (Lipaphis erysimi Kaltenbach, Hemiptera: Aphididae). Rapid colonization by the nymphs makes it difficult to protect the crop through agrochemicals. Aphids release effector molecules to modulate the host-defence responses. Glucosinolates (GSLs) extensively found in Brassicaceae family, are hydrolysed by myrosinase into toxic compounds that deter herbivore insects. Here, we investigated the differential activation of the glucosinolate-myrosinase pathway in mustard manifesting susceptibility and resistance to different aphid species. Mustard plants were challenged by two different aphid species mustard aphid and cowpea aphid (Aphis craccivora Koch, Hemiptera: Aphididae) leading to complete host-susceptibility in one case and resistance in the other, respectively. Differential regulation of the GSL biosynthetic pathway and myrosinase activity was assessed by gene expression study and ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC- QToF-ESL-MS). Gene expression study identified selective transcriptional attenuation of the key GSL biosynthetic and myrosinase gene in mustard when challenged with mustard aphid. In contrary, the activation of GSL biosynthetic genes in conjunction with myrosinase at the transcriptional level was profound in mustard, when challenged with cowpea aphid. UPLC-MS analysis showed higher turnover in the hydrolysis of glucosinolates by myrosinase which led to concomitant generation of glucose as byproduct in response to cowpea aphid in mustard plants. GSL-myrosinase pathway is specifically attenuated by the successful aphid species in mustard and thus plays a pivotal role in determining the outcome of the B. juncea-aphid interaction. The results open up a new genetic modification strategy for developing resistance against aphids.

The effects of oil adjuvant on the degradation of spirotetramat and its metabolites in apple cultivation

Spirotetramat is a frequently used insecticide in integrated pest management (IPM) strategies against rosy apple aphid (Dysaphis plantaginea) and woolly apple aphid (Eriosoma lanigerum) in apple cultivation. It is known that paraffin oil adjuvants increase the effect of spirotetramat against aphids. In contrast, there is a knowledge gap regarding the effects of co-applied paraffin (mineral or petroleum) oil on the degradation of spirotetramat and its metabolites (B-enol, B-keto, B-mono, and B-glu), which has not been previously investigated. Spirotetramat combined with formulated paraffin oil was tested against two aphid species and the residues of spirotetramat and its metabolites on leaves and apples were quantified using Liquid Chromatography coupled with tandem Mass Spectrometry (LC-MS/MS). The results showed that spirotetramat is highly effective against D. plantaginea, decreasing infestation by almost 100%. Furthermore, spirotetramat was shown to be effective against E. lanigerum, the reduction in infestation ranged between 67.9 and 97.7% during the last validation date. The addition of paraffin oil increased the effect of spirotetramat and affected its degradation, indicating that its efficacy could be connected to its metabolites. B-mono and B-glu were the most persistent metabolites in apple fruit overall when paraffin oil was applied.

Rapid screening for resistance to Sitobion avenae (F.) and Rhopalosiphum padi (L.) in winter wheat seedlings and selection of efficient assessment methods.

Sitobion avenae (F.) and Rhopalosiphum padi (L.) are harmful pests of wheat [Triticum aestivum (L.)]. No genetic resistance against the aphids has been identified in commercial wheat varieties and resistance phenotyping can be time-consuming and laborious. Here, we tested a high-throughput phenotyping method to screen 29 commercial winter wheat varieties for alate antixenosis and antibiosis. We validated this method using comprehensive behavioural analyses, including alate attraction to volatile organic compounds (VOCs) and a feeding bioassay using an electrical penetration graph (EPG), subsequently highlighting possible sources of resistance. We observed differences in alate behaviour upon assessing alate settlement on wheat seedlings and attraction towards VOCs, revealing the importance of visual and early post-alighting cues for alate host selection. Aphid settlement was four times higher on the most preferred variety than on the least preferred variety. Using an EPG bioassay, we identified phloem feeding and stylet derailment parameters linked to resistance. We found antibiosis assessment on detached leaves to be an inadequate screen because it produced results inconsistent with intact leaves assessment. Alate and nymph mortality were identified as key traits signifying antibiosis, showing significant positive relationships with alate reproduction and nymph mean relative growth rate. Overall, antixenosis and antibiosis varietal responses were consistent for both aphid species. Alate settlement on wheat seedlings was a more efficient antixenosis screen than an olfactometer assay using VOCs. In addition to assessing alate and nymph survival for antibiosis, this allows for more rapid phenotyping of large numbers of genotypes to identify novel aphid resistance genes for varietal improvement. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Aphidicidal activity of nano-emulsions of spearmint oil and carvone against Rhopalosiphum maidis and Sitobion avenae

Different species of aphids, responsible for severe yield losses of cereal crops including wheat, (Triticum aestivum L.) are managed by insecticides, which are harmful to organisms and the environment under field conditions. Therefore, an environment friendly aphidicidal product of plant origin is required. Mentha spicata oil was found to be rich in carvone (81.88%), but the use of its oil and carvone in crop protection is lacking due to their volatility, poor solubility, and stability. A nanoformulaton not only solves these problems but also improve the efficacy and dose of the bioactive compounds. Thus, nano-emulsions of the oil and carvone prepared were characterized, and evaluated against Rhopalosiphum maidis (corn aphid) and Sitobion avenae (wheat aphid) The average droplet size of nano-emulsions of the oil and carvone was found to be 22.1 and 41.21 nm. Nano-emulsion of carvone exhibited higher aphid mortality (LC50 = 0.87–1.94 mg/mL) at 24 h and acetylcholinesterase inhibitory activity (IC50 = 0.07–3.83 mg/mL) compared to the nano-emulsion of the oil (LC50 = 2.87–2.81 mg/mL; IC50 = 1.66–5.34 mg/mL). The repellence index (RI) in nano-emulsion of essential oil was found to be higher (84.73 and 81.72%) at the highest concentration (0.05 µL/cm2) than that of carvone (77.59 and 80.98%) for R. maidis and S. avenae. Further, in silico studies also revealed the favourable binding energy (− 6.6 to − 8.5 kcal/mol) of the main compounds in the oil with acetylcholinesterase, facilitated by hydrophobic interactions and hydrogen bonding. This study suggests that the nano-emulsions of the essential oil and carvone can be explored under field conditions to establish efficacy for their utilization as aphidicidal and repellent products against aphids. In the present study, aphidicial and repellent activities of its essential oil and carvone were reported for the first time against R.maidis and S.avenae.

Biological Manifestation of Different Temperature Regimes and Certain Insecticides on Cheilomenes sexmaculata (Fab.) Preying on Cowpea Aphid, Aphis craccivora Koch

Background: Ladybird beetles are great bio-control agents and campodeiform grubs of these little predators are able to devour aphids in a voracious fashion. They feed on a wide array of aphid species most noticeably on the infamous black aphids or cowpea aphids Aphis craccivora (Koch). Methods: The growth and feeding potential of C. sexmaculata were studied in the laboratory of the Department of Entomology, Faculty of Agricultural Sciences (Institute of Agricultural Sciences), SOA Deemed to be University, Bhubaneswar, India at four different temperatures 20°C, 25°C, 30°C and 35°C during 2021-2022. Result: The life history parameters indicated that the duration of eggs, larvae, pupae, adult males and adult females was longest at 30°C and shortest at 20°C. Such variations were also observed in morphometry and feeding potential. The trend was 30°C greater than 25°C greater than 35°C greater than 20°C. In the case of feeding potential the trend was adult female greater than adult male greater than 4th instar greater than 3rd instar greater than 2nd instar greater than 1st instar across all temperatures. Adult females lived longer than males and thereby consumed more aphids than males. Maximum consumption was seen in case of adult female at 30°C which was 633±5.71 aphids and least feeding was seen at 20°C by 1st instar grub which was 8.9±0.56 aphids. The effect of insecticides in direct spray method indicated that dimethoate 30EC killed more ladybirds and clothianidin 50% WDG killed the least. This trend was strong across all temperatures and insect growth stages. The feed contamination method indicated that clothianidin 50% WDG, imidacloprid 17.8% SL and thiamethoxam 25% WG produced higher mortality rates than direct contamination method. All insecticides showed increased mortality up to 72 h and the mortality trend was 72 HAT greater than 48 HAT greater than 24 HAT. The mortality rate of immature individuals is higher than that of adults.

Aphids of Iran: their host plants and distribution

A reviewed checklist of aphids (Hemiptera: Sternorrhyncha: Aphidomorpha) species recorded in Iran is presented as a catalogue in alphabetical order considering recent taxonomic changes. In total, 572 species along with 29 subspecies within 148 genera, belonging to 13 subfamilies, 3 families and 3 superfamilies of Aphidomorpha are presented. In addition, the list of host plants and distribution of the aphid species in Iran and the related references are provided.

Influence of genetic and environmental factors on the success of endosymbiont transfers in pest aphids.

There is increasing interest in exploring how endosymbionts could be useful in pest control, including in aphids, which can carry a diversity of endosymbionts. Endosymbionts often have a large impact on host traits, and their presence can be self-sustaining. Identifying useful host-endosymbiont combinations for pest control is facilitated by the transfer of specific endosymbionts into target species, particularly if the species lacks the endosymbiont. Here, we complete a comprehensive literature review, which included 56 relevant papers on endosymbiont transfer experiments in aphids, to uncover factors that might influence transfer success. We then report on our own microinjection attempts of diverse facultative endosymbionts from a range of donor species into three agriculturally important aphid species as recipients: the green peach aphid (Myzus persicae), bird cherry-oat aphid (Rhopalosiphum padi), and Russian wheat aphid (Diuraphis noxia). Combining this information, we consider reasons that impact the successful establishment of lines carrying transferred endosymbionts. These include a lack of stability in donors, deleterious effects on host fitness, the absence of plant-based (versus vertical) transmission, high genetic variation in the endosymbiont, and susceptibility of an infection to environmental factors. Taking these factors into account should help in increasing success rates in future introductions.

Adenophoraphis, a new aphid genus from Kazakhstan (Hemiptera: Aphididae: Macrosiphini)

Currently, 889 species of aphids from three families are known in Kazakhstan: Adelgidae (10 species), Phylloxeridae (2), Aphididae (877) [1]. A new to science genus of aphids Adenophoraphis gen. n. and a new species Adenophoraphis burabaica sp. n. described from Kazakhstan. The specimens of the new taxon were collected in Akmola Region of the northern Kazakhstan in 2002. The new genus belongs to the subtribe Macrosiphina of the tribe Macrosiphini (Aphidinae). It lives on Adenophora liliifolia (L.) A. DC, no ant attendance was observed. During the collection period, only apterous viviparous females were found. The specimens were collected in a deciduous forest, in the Kazakh uplands, on the Kokshetau Upland. The new genus belongs to the subtribe Macrosiphina of the tribe Macrosiphini of the subfamily Aphidinae. In addition to the new genus, the other members of Macrosiphina inhabiting Campanulaceae include Campanulaphis Kadyrbekov, 2016, Megouroleucon Miyazaki, 1971, Tshernovaia Holman et Szelegiewicz, 1964 and Uroleucon Mordvilko, 1914.

Enhancing protein signal detection in asexual and viviparous pea aphids: A guided protocol for tissue dissection and proteinase K treatment

Aphids, as hemipteran insects, reproduce via parthenogenesis and viviparity, resulting in rapid and exponential offspring production. To investigate the molecular mechanisms underlying parthenogenetic viviparity in asexual aphids, precise protein detection through immunostaining is essential. Our previous research demonstrated the need for proteinase K (PK) treatment to improve tissue permeability, enabling antibodies targeting the germ-cell marker Ap-Vas1 to access gastrulating and later-stage embryos. However, optimal PK digestion protocols have not been thoroughly explored. In this study, we propose strategies to optimize PK digestion conditions for early, middle, and late-stage pea aphid embryos, which have varying tissue thicknesses. Additionally, we extend the application of PK treatment to salivary glands, a representative somatic tissue, by optimizing conditions for antibody penetration against the salivary gland marker C002. To enhance spatial precision in signal detection, we provide a detailed protocol for tissue dissection specific to pea aphids, focusing on the preservation of tissue integrity. These comprehensive guidelines, covering tissue dissection and PK titration, are expected to improve the specificity and intensity of protein signals in pea aphids and other aphid species.•Provide aphid-specific dissection methods to obtain intact embryos and salivary glands.•Present strategies for optimizing PK treatment conditions across different tissue types.

Yellow Dwarf Virus Resistance in Barley: Phenotyping, Remote Imagery, and Virus-Vector Characterization.

Yellow dwarf viruses (YDVs) spread by aphids are some of the most economically important barley (Hordeum vulgare) virus-vector complexes worldwide. Detection and control of these viruses are critical components in the production of barley, wheat, and numerous other grasses of agricultural importance. Genetic control of plant diseases is often preferable to chemical control to reduce the environmental and economic cost of foliar insecticides. Accordingly, the objectives of this work were to (i) screen a barley population for resistance to YDVs under natural infection using phenotypic assessment of disease symptoms, (ii) implement drone imagery to further assess resistance and test its utility as a disease screening tool, (iii) identify the prevailing virus and vector types in the experimental environment, and (iv) perform a genome-wide association study to identify genomic regions associated with measured traits. Significant genetic differences were found in a population of 192 barley inbred lines regarding their YDV symptom severity, and symptoms were moderately to highly correlated with grain yield. The YDV severity measured with aerial imaging was highly correlated with on-the-ground estimates (r = 0.65). Three aphid species vectoring three YDV species were identified with no apparent genotypic influence on their distribution. A quantitative trait locus impacting YDV resistance was detected on chromosome 2H, albeit undetected using aerial imaging. However, quantitative trait loci for canopy cover and mean normalized difference vegetation index were successfully mapped using the drone. This work provides a framework for utilizing drone imagery in future resistance breeding efforts for YDVs in cereals and grasses, as well as in other virus-vector disease complexes.

Takecallis nigroantennatus Wieczorek (Hemiptera: Aphididae) – implications of the ability to holocycle and overwintering of eggs on the spread of a potentially invasive bamboo aphid species

Takecallis nigroantennatus Wieczorek (Hemiptera: Aphididae) – implications of the ability to holocycle and overwintering of eggs on the spread of a potentially invasive bamboo aphid species

Analysis of Twenty Years of Suction Trap Data on the Flight Activity of Myzus persicae and Brevicoryne brassicae, Two Main Vectors of Oilseed Rape Infection Viruses

Myzus persicae and Brevicoryne brassicae are the main aphid pests and vectors of viruses that attack many crops, including oilseed rape, the most commonly grown dicotyledonous crop in the Czech Republic. In this study, we analysed the flight activity of both aphids from five suction traps over 20 years (2004–2023). We focussed on (i) the influence of the ban on seed dressing with neonicotinoids on aphid catches, (ii) the influence of the average temperature on flight activity, and (iii) the number of males/females caught in the suction traps. We compared the data on aphid flight activity at the coldest and warmest sites and found that migration starts about 10 days earlier at the warmest site than at the coldest site and that aphid populations are more numerous here. The number of catches in suction traps was observed for both aphids after the ban on neonicotinoids was significantly increased. For M. persicae, it was about 9 times higher, while for B. brassicae, it was about 1.3 times higher. In addition, we observed a significant decrease in the number of males in M. persicae with a simultaneous increase in the number of females (in autumn), which could be an indication of the formation of anholocyclic populations. Overall, our results showed a significantly high abundance of both aphid species depending on the observed locations, which seems to be related to the ban of neonicotinoids. Therefore, an effective alternative is needed to improve the control of aphid vectors that can ensure the stability of crops against aphid-transmitted virus diseases.

Effects of host plants on aphid feeding behavior, fitness, and Buchnera aphidicola titer.

Aphids are sap-feeding plant pests that depend on their symbiotic relationships with the primary endosymbiont Buchnera aphidicola to adapt to impoverished diets. However, how the host plant affects the aphid primary symbiont and aphid adaptation to host plant transfer are poorly known. In this study, aphid symbiont screening and genotype identification were used to establish 2 aphid strains (Rhopalosiphum maidis [Rm] and Rhopalosiphum padi [Rp] strains) containing only Buchnera without any secondary symbionts for both wheat aphid species (R. maidis and R. padi). Aphid fitness and Buchnera titers were unstable on some of these host plants after transferring to novel host plants (G1-G5), which were influenced by host plant species and generations; however, they stabilized after prolonged feeding on the same plants for 10 generations. The electropenetrography (EPG) records showed that the allocation of aphid feeding time was significantly distinct in the 6 host plants; aphids had more intracellular punctures and spent more nonprobing time on green bristlegrass which was not conducive to its growth compared with other plants. The content of soluble sugar, soluble protein, and amino acid in the leaves of the 6 host plants were also clearly separated. The correlation coefficient analysis showed that the nutrient contents of host plants had significant correlations with aphid feeding behaviors, fitness, and Buchnera titers. In the meantime, aphid fitness, and Buchnera titers were also affected by aphid feeding behaviors. Also, Buchnera titers of aphid natural populations on 6 host plants showed a visible difference. Our study deepened our understanding of the interaction among aphids, endosymbionts, and host plants, indicating that the host plant nutrient content is a predominant factor affecting aphid adaptation to their diet, initially affecting aphid feeding behaviors, and further affecting aphid fitness and Buchnera titers, which would further contribute to exploiting new available strategies for aphid control.

Influence of Weather Conditions and the Aphid Population on the Potato Virus Y Infection of Tobacco in the Field

Potato virus Y (PVY) is a major tobacco (Nicotiana tabacum L.) pathogen that causes severe crop losses. We studied the influence of meteorological factors and a population of twelve aphid species on the development of PVY in field-grown tobacco from 1996 to 2010 in Poland. Three PVY-susceptible tobacco varieties were used in the study. The mean virus incidence ranged from 18% in 2010 to almost 99% in 1996, 2004, and 2009. For determining the relationship between tobacco plant infection and meteorological conditions and aphid populations, logistic regression analysis was used. It was found that the probability of PVY infection is significantly dependent on the average air temperature, relative humidity, number of days with an average temperature of at least 25 °C, and the abundance of Aphis fabae and Brachycaudus helichrysi. The probability of infection of tobacco plants with potato virus Y decreased with increasing air temperature and relative humidity. In addition, with each subsequent day with a temperature of at least 25 °C, the risk of infection decreased by 24%. Furthermore, it was often observed that high populations of Aphis fabae and Brachycaudus helichrysi were associated with a high incidence of virus infection in tobacco plants.

RpUGT344J7 is involved in the reproduction switch of Rhopalosiphum padi with holocyclic life cycle.

Many aphid species exhibit both cyclical parthenogenesis (CP) and the obligate parthenogenesis (OP) life history, which are genetically determined. In CP aphid lineages, the parthenogenetic individuals can switch from asexual to sexual reproduction quickly in response to environmental factors such as changes in photoperiod and temperature. However, the OP aphid lineages do not undergo sexual reproduction under any conditions. So far, mechanisms underlying the reproduction switch in CP aphids have not been fully elucidated. Rhopalosiphum padi, a serious worldwide insect pest of wheat, has both CP and OP lineages. Uridine diphosphate-glycosyltransferases (UGTs) are enzymes that participate in the metabolic detoxification of xenobiotics. Here, we identified 43 RpUGT genes from R. padi genome and transcriptome sequences, and found that: (1) the UGT content of the CP lineage was significantly higher than that in the OP lineage at the key time points when CP lineage mainly produce virginoparae, gynoparae, and males under inducing condition, while there were no significant difference under normal conditions; (2) RpUGT344J7 gene was highly expressed during the time points when CP lineages produce gynopara and males; (3) the critical time points for CP lineages to produce virginoparaee, gynoparae, and males were affected when the CP lineages were injected with dsRpUGT344J7; (4) the knockdown of RpUGT344J7 caused a significant reduction in the total number of virginoparae, gynoparae, and males in the offspring under inducing condition. The findings contribute to our understanding of the molecular mechanisms underlying the quick shift from asexual to sexual reproduction in aphid species.

Overexpression of SmUGGT1 Confers Imidacloprid Resistance to Sitobion miscanthi (Takahashi).

Sitobion miscanthi, the main species of wheat aphids, is one kind of harmful pest. Chemical insecticides are the important agrochemical products to effectively control wheat aphids. However, the broad application has led to serious resistance of pests to several insecticides, and understanding insecticide resistance mechanisms is critical for integrated pest management. In this study, SmUGGT1, a new uridine diphosphate (UDP)-glycosyltransferase (UGT) gene, was cloned and more strongly expressed in the SM-R (the resistant strain to imidacloprid) than in the SM-S (the susceptible strain to imidacloprid). The increased susceptibility to imidacloprid was observed after silencing SmUGGT1, indicating that it can be related to the resistance to imidacloprid. Subsequently, SmUGGT1 regulated post-transcriptionally in the coding sequences (CDs) by miR-81 was verified and involved in the resistance to imidacloprid in S. miscanthi. This finding is crucial in the roles of UGT involved in insecticide resistance management in pests.

New okra genotypes for the management of aphids (Hemiptera: Aphididae) in the diverse ecological landscapes of Central Africa.

Various aphid species, including Aphis gossypii Glover (Hemiptera: Aphididae), are considered important pests of okra and other vegetables. Previous studies under 1 environment in Cameroon, Central Africa, had found multiple okra genotypes with resistance to A. gossypii. However, the stability and yield performance of the "resistant" genotypes across different environments were unknown. Ten previously identified aphid-resistant okra genotypes along with 1 commercial variety and a local landrace (specific to a given location) were compared during 2 seasons in replicated trials in 4 agro-ecological zones of Cameroon that also represent large areas of Central Africa. Aphid populations and okra yield parameters were evaluated. Breeding values were predicted using a linear mixed model for all data, and genotypes by location interactions were identified. The area under the infestation pressure curve (AUIPC) was calculated using aphid count data and subjected to resistance analysis. The Local-the most susceptible with the highest breeding value (+2.33)-and VI060794-one of the moderately resistant-genotypes had the highest yield per hectare. The only resistant genotype VI036213 had the lowest breeding value (-2.20). Genotype × location interactions were significant for yield, pod width, and plant height, while location variance was significant for all parameters evaluated. When considering that higher aphid densities could lead to greater pesticide use and, therefore higher production and environmental costs, the high-yielding VI060794-with moderate aphid resistance across multiple environments-presents an alternative or substitute for local landraces across multiple agro-ecologies of Cameroon and (by extension) Central Africa.

'Drifting' Buchnera genomes track the microevolutionary trajectories of their aphid hosts.

Evolution of Buchnera-aphid host symbioses is often studied among species at macroevolutionary scales. Investigations within species offer a different perspective about how eco-evolutionary processes shape patterns of genetic variation at microevolutionary scales. Our study leverages new and publicly available whole-genome sequencing data to study Buchnera-aphid host evolution in Myzus persicae, the peach potato aphid, a globally invasive and polyphagous pest. Across 43 different asexual, clonally reproducing isofemale strains, we examined patterns of genomic covariation between Buchnera and their aphid host and considered the distribution of mutations in protein-coding regions of the Buchnera genome. We found Buchnera polymorphisms within aphid strains, suggesting the presence of genetically different Buchnera strains within the same clonal lineage. Genetic distance between pairs of Buchnera samples was positively correlated to genetic distance between their aphid hosts, indicating shared evolutionary histories. However, there was no segregation of genetic variation for both M. persicae and Buchnera with plant host (Brassicaceae and non-tobacco Solanaceae) and no associations between genetic and geographic distance at global or regional spatial scales. Abundance patterns of non-synonymous mutations were similar to synonymous mutations in the Buchnera genome, and both mutation classes had similar site frequency spectra. We hypothesize that a predominance of neutral processes results in the Buchnera of M. persicae to simply 'drift' with the evolutionary trajectory of their aphid hosts. Our study presents a unique microevolutionary characterization of Buchnera-aphid host genomic covariation across multiple aphid clones. This provides a new perspective on the eco-evolutionary processes generating and maintaining polymorphisms in a major pest aphid species and its obligate primary endosymbiont.