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The Asian citrus psyllid (ACP) is the main vector of Citrus Huanglongbing, the most damaging citrus disease, causing significant financial losses in the citrus industry. Global warming has expanded the habitat of this pest, allowing it to continue its northward migration to China. Population genetic information of ACP is fundamentally essential for species management. This study investigated the genetic diversity and population structure of Chinese ACP using the mitochondrial cytochrome oxidase subunit I gene by dataset comprised 721 sequences from 27 geographic sites in China. Low haplotype diversity (0.323 ± 0.022) and low nucleotide diversity (0.00071 ± 0.00007) were observed in the entire population, which may indicate recent founder events. Twenty-three haplotypes were identified and clustered into 2 haplogroups: haplogroup I and haplogroup II. Haplogroup II included only 2 unique haplotypes, which occurred exclusively in the Southwest China ACP population. Genetic differentiation analyses were also indicative of Southwest China population was significantly differentiated from the remaining populations. Demographic history analysis showed that ACP population in China has experienced demographic expansion. Our results provided a better understanding of the genetic distribution patterns and structures of ACP populations in China., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America.)

Background: The white-backed planthopper (WBPH), Sogatella furcifera (Horváth) (Hemiptera, Delphacidae), is a migratory pest of rice in Asia. Shandong Province, in northern China, is located on the migration pathway of WBPH between southern and northeast China. The potential sources of WBPH in northern China are poorly understood. We studied the sources of WBPH in Shandong Province by determining the population genetic structure of WBPH in 18 sites distributed in Shandong and in six regions of the Greater Mekong Subregion (GMS). We used mitochondrial gene and single-nucleotide polymorphism (SNP) markers for analysis., Results: All of the WBPH populations studied in the seven regions had low genetic diversity. Pairwise F ST values based on mtDNA ranged from - 0.061 to 0.285, while F ST based on SNP data ranged from - 0.007 to 0.009. These two molecular markers revealed that 4.40% (mtDNA) and 0.19% (SNP) genetic variation could be explained by the interpopulation variation, while the rest came from intrapopulation variation. The populations in the seven geographic regions comprised four hypothetical genetic clusters (K = 4) not associated with geographic location. Eighty-four of 129 individuals distributed across the given area were designated as recent migrants or of admixed ancestry. Although the substantial migration presented, a weak but significant correlation between genetic and geographic distances was found (r = 0.083, P = 0.004)., Conclusion: The Greater Mekong Subregion was the main genetic source of WBPH in Shandong, while other source populations may also exist. The genetic structure of WBPH is shaped by both migration and geographic barriers. These results help clarify the migration route and the source of WBPH in northern China.

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex and widely distributed throughout tropical and subtropical regions. To understand the B. tabaci cryptic species diversity in China more comprehensively, in the year 2014 and 2016, a large-scale sampling was conducted from the famous biodiversity hotspot of China, Yunnan province. Mitochondrial cytochrome oxidase I gene sequences were used to identify new putative cryptic species. Phylogenetic analyses were performed using Bayesian methods to evaluate the position of new cryptic species in the context of the B. tabaci diversity in Asia. Two new cryptic species, China 5 and Asia V were identified. In total, 19 B. tabaci cryptic species are present in China, two invasive (MED and MEAM1) and 17 indigenous. A new sibling species of B. tabaci was first defined and reported. Based on the mtCOI sequences and haplotype network analyses, the genetic diversity of MED was far higher than MEAM1. We confirmed the exotic MED was originated from the western Mediterranean regions and first invaded into Yunnan, China. The genetic structures of other four indigenous species (Asia I, Asia II 1, Asia II 6, and China 1) with relatively wide distribution ranges in China were also discussed.

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), with its global distribution and extensive genetic diversity, is now known to be a complex of over 35 cryptic species. However, a satisfactory resolution of the systematics of this species complex is yet to be achieved. Here, we designed experiments to examine reproductive compatibility among species with different levels of mitochondrial cytochrome oxidase I (mtCOI) divergence. The data show that putative species with mtCOI divergence of >8% between them consistently exhibited complete reproductive isolation. However, two of the putative species, Asia II 9 and Asia II 3, with mtCOI divergence of 4.47% between them, exhibited near complete reproductive compatibility in one direction of their cross, and partial reproductive compatibility in the other direction. Together with some recent reports on this topic from the literature, our data indicates that, while divergence in the mtCOI sequences provides a valid molecular marker for species delimitation in most clades, more genetic markers and more sophisticated molecular phylogeny will be required to achieve adequate delimitation of all species in this whitefly complex. While many attempts have been made to examine the reproductive compatibility among genetic groups of the B. tabaci complex, our study represents the first effort to conduct crossing experiments with putative species that were chosen with considerations of their genetic divergence. In light of the new data, we discuss the best strategy and protocols to conduct further molecular phylogenetic analysis and crossing trials, in order to reveal the overall pattern of reproductive incompatibility among species of this whitefly complex., (© 2015 Institute of Zoology, Chinese Academy of Sciences.)

The whitefly, Bemisia tabaci (Hemiptera: Aleyrodidiae), is a cryptic species complex comprising a minimum of 24 cryptic species. Some members of this complex are important agricultural pests, causing considerable damage to vegetable as well as ornamental and horticultural crops. Asia I, one of the cryptic species of B. tabaci, is widely distributed in Asia. One hundred and sixty mitochondrial cytochrome oxidase I (COI) sequences from eight countries have been analyzed to investigate the geographic origin and current genetic structure of this cryptic species. Sixty different haplotypes were identified, with levels of genetic distances ranging from 0.001 to 0.021. A sign of possible genetic differentiation emerges from the differential distribution of dominant haplotypes in Indonesia and India compared to China. A possible ancient separation between Asia I in India and Indonesia and secondary contact in China has been hypothesized.

Based on research carried out from 2016 to 2018 there are twenty-six species of aphids of the tribe Eulachnini in Lithuania. Seventeen are members of the subgenus Cinara of the genus Cinara, three of the subgenus Cupressobium and two of the subgenus Schizolachnus. In addition, there are four species of the genus Eulachnus. Summarized information on the distribution and host specificity of Eulachnini in Lithuania is presented. Nine species were in all climatic regions of Lithuania: C. (Cinara) brauni, C. (Cinara) hyperophila, C. (Cinara) neubergi, C. (Cinara) piceicola, C. (Cinara) pinea, C. (Cinara) pini, C. (Cinara) pruinosa, C. (Cupressobium) cupressi and C. (Cupressobium) juniperi. Five species of Lithuanian Eulachnini inhabit host plants of the genus Picea, three live on Larix, thirteen on Pinus, one on Abies, one on Thuja and three on Juniperus. Cinara (Cinara) piniphila was recorded on Pinus mugo and C. (Cinara) nuda on Pinus heldreichii for the first time. Partial COI and EF-1α sequences of C. (Cinara) hyperophila, C. (Cinara) pilosa and C. (Cinara) piceicola were obtained for the first time. Partial sequences of mitochondrial (COI) and nuclear (EF-1α) DNA of Lithuanian samples were used to explore molecular diversity using NJ trees, Automatic Barcode Gap Discovery (ABGD), General Mixed Yule Coalescent (GMYC) and Poisson Tree Processes (PTP). Species delimitation using GMYC (both on COI and EF-1α sequences), PTP (BI on COI) and ABGD (EF-1α) were the most consistent with traditional classifications. Pairwise between-species sample divergences (COI and EF-1α fragments) of the samples of the species complex C. (Cinara) pinea - C. (Cinara) piniphila indicate it is composed of a single species. Of the species of aphids that live on conifers, there are seven species of the tribe Eulachnini that are likely to shortly colonize Lithuania.

The bronze bug, Thaumastocoris peregrinus, is an endemic Australian eucalypt pest that has become a serious threat to the global forestry industry. Following a large outbreak within its native range in 2002, introduced populations of the bronze bug appeared in South Africa and Argentina. Since then, T. peregrinus has spread rapidly around the world, with the number of reported incursions increasing steadily. Despite the problems posed by the bronze bug, little is known about its global invasion pathways. In this study, we used multiple different population genetic methods to (1) gain new insight into aspects of bronze bug population history within Australia, and (2) characterise the spread of the bronze bug throughout South America, South Africa, New Zealand and the Mediterranean Basin. Taken together, the genetic data and the outbreak records suggest that, across the international regions surveyed, at least three separate introductions of T. peregrinus from Australia have occurred over the decade 2003–2012—one into South Africa, another into Argentina and a third into New Zealand—each of which is likely to have originated in Sydney. Populations in Europe and Israel appear to have become established from individuals introduced from South America, rather than from within the native Australian range, suggesting the existence of a bridgehead effect. These findings provide an important framework for understanding the global spread of invasive bronze bug populations. They may be used to inform management decisions and improve the effectiveness of control strategies. [ABSTRACT FROM AUTHOR]

Leafhoppers (Cicadellidae) occur in all biogeographical regions and feed on a wide range of host plants. Classic identification of leafhoppers is based only on the morphology of male genitalia, while DNA barcoding is an effective tool to identify different leafhopper species in any stage of their life cycle. Phylogenetic relationships among leafhoppers remain unexplored, but recent phylogenies have begun to interpret the evolutionary relationships of previously recognized tribes and subfamilies. Here we used mitochondrial Cytochrome Oxidase I sequences to barcode and determine the phylogenetic relationship among eight leafhopper genera collected from Egypt. Eight leafhopper samples from eight different genera were collected from various plants using a sweeping net and aspirator. Males of seven species were available while females only were available from the one genus (Austroagallia sp.). Novel leafhopper-specific mtDNA COI degenerate primers were designed. Our results showed that the mean of intraspecific COI sequence divergence in leafhoppers was 0.45%, with a range from 0.15% to 1.23%, and the divergences of most species were over 2%. For the first time, we were exploring the evolutionary relationships among surveyed genera (Austroagallia, Empoasca, Eupteryx, Exitianus, Macrosteles, Nephotettix, and Orosius) using a robust phylogenetic supertree. Our results demonstrate that DNA barcoding is likely to be a powerful tool for identifying and understanding leafhoppers' evolution. [ABSTRACT FROM AUTHOR]

Based on research carried out from 2016 to 2018 there are twenty-six species of aphids of the tribe Eulachnini in Lithuania. Seventeen are members of the subgenus Cinara of the genus Cinara, three of the subgenus Cupressobium and two of the subgenus Schizolachnus. In addition, there are four species of the genus Eulachnus. Summarized information on the distribution and host specificity of Eulachnini in Lithuania is presented. Nine species were in all climatic regions of Lithuania: C. (Cinara) brauni, C. (Cinara) hyperophila, C. (Cinara) neubergi, C. (Cinara) piceicola, C. (Cinara) pinea, C. (Cinara) pini, C. (Cinara) pruinosa, C. (Cupressobium) cupressi and C. (Cupressobium) juniperi. Five species of Lithuanian Eulachnini inhabit host plants of the genus Picea, three live on Larix, thirteen on Pinus, one on Abies, one on Thuja and three on Juniperus. Cinara (Cinara) piniphila was recorded on Pinus mugo and C. (Cinara) nuda on Pinus heldreichii for the fi rst time. Partial COI and EF-1a sequences of C. (Cinara) hyperophila, C. (Cinara) pilosa and C. (Cinara) piceicola were obtained for the fi rst time. Partial sequences of mitochondrial (COI) and nuclear (EF-1a) DNA of Lithuanian samples were used to explore molecular diversity using NJ trees, Automatic Barcode Gap Discovery (ABGD), General Mixed Yule Coalescent (GMYC) and Poisson Tree Processes (PTP). Species delimitation using GMYC (both on COI and EF-1a sequences), PTP (BI on COI) and ABGD (EF-1a) were the most consistent with traditional classifi cations. Pairwise between-species sample divergences (COI and EF-1a fragments) of the samples of the species complex C. (Cinara) pinea - C. (Cinara) piniphila indicate it is composed of a single species. Of the species of aphids that live on conifers, there are seven species of the tribe Eulachnini that are likely to shortly colonize Lithuania. [ABSTRACT FROM AUTHOR]

Biological invasions represent a major threat to agriculture and forestry across the globe. Thaumastocoris peregrinus is a small sap-sucking heteropteran bug that has recently invaded a number of eucalypt plantations worldwide from its native range in Australia. To date, no studies have examined the range of this insect within Australia, and its population genetics remain poorly understood. We sampled T. peregrinus from 16 populations from South East Queensland, across New South Wales (NSW) and Victoria to south-eastern South Australia, and generated microsatellite and mtDNA data for ~ 200 individuals. Population genetic analyses consistently revealed moderate levels of genetic isolation by distance among populations across the range. Nonetheless, T. peregrinus has undergone dispersal across large distances, as revealed by the presence of identical mitochondrial haplotypes in both South East Queensland and South Australia. Two populations within the Sydney area (NSW) were divergent from other populations based on STRUCTURE and factorial correspondence analysis. They also had relatively low allelic richness and haplotype diversity indices. These results suggest they are the result of a relatively recent invasion event, consistent with their discovery in 2001. Pairwise genetic distance analyses suggest that the source of the invasion may have been central NSW. Our study provides an important framework for understanding the biology of this pest in its native environment, and may have implications for determining how it has invaded multiple areas worldwide. [ABSTRACT FROM AUTHOR]

Aphid species Aphis pomi (de Geer, 1773) is oligophagous on pomoideous host plants, whilst Aphis spiraecola Patch, 1914 is a polyphagous species alternating between Spiraea spp., its primary host, and a wide variety of secondary hosts, also including pomoideous species. Despite the biological distinction, these species are difficult to separate using their morphological characters. Partial sequences of mitochondrial COI and nuclear EF-1α genes were analyzed for samples from Central and Eastern Europe, Germany, Bulgaria, Italy, Turkey, China together with available data from GenBank. Interspecific pairwise sample divergences of the COI fragment ranged from 3.1 to 4.3%. One COI haplotype of A. pomi was predominant (n = 24), with a pan European distribution. The most abundant COI haplotype of A. spiraecola (n = 16) occurred in Lithuania, Latvia, Poland, Italy, Turkey and China. Interspecific pairwise sample divergences of the EF-1α fragment ranged from 0.6 to 1.2%. Analyzed partial sequences of EF-1α were identical in A. pomi. The most abundant EF-1α haplotype of A. spiraecola (n = 14) occurred in Lithuania, Poland, Italy, Turkey and China. The length of ultimate rostral segment appeared to be the most reliable morphological character for discrimination between apple and spirea aphid species. It allowed a 100% correct identification of A. pomi (n = 143) and 91.5% of A. spiraecola (n = 94) specimens in the European samples used for the molecular analysis. The existence of A. spiraecola in the Eastern Baltic region of Europe is documented for the first time.

Aphid species Aphis pomi (de Geer, 1773) is oligophagous on pomoideous host plants, whilst Aphis spiraecola Patch, 1914 is a polyphagous species alternating between Spiraea spp., its primary host, and a wide variety of secondary hosts, also including pomoideous species. Despite the biological distinction, these species are difficult to separate using their morphological characters. Partial sequences of mitochondrial COI and nuclear EF-1α genes were analyzed for samples from Central and Eastern Europe, Germany, Bulgaria, Italy, Turkey, China together with available data from GenBank. Interspecific pairwise sample divergences of the COI fragment ranged from 3.1 to 4.3%. One COI haplotype of A. pomi was predominant (n = 24), with a pan European distribution. The most abundant COI haplotype of A. spiraecola (n = 16) occurred in Lithuania, Latvia, Poland, Italy, Turkey and China. Interspecific pairwise sample divergences of the EF-1α fragment ranged from 0.6 to 1.2%. Analyzed partial sequences of EF-1α were identical in A. pomi. The most abundant EF-1α haplotype of A. spiraecola (n = 14) occurred in Lithuania, Poland, Italy, Turkey and China. The length of ultimate rostral segment appeared to be the most reliable morphological character for discrimination between apple and spirea aphid species. It allowed a 100% correct identification of A. pomi (n = 143) and 91.5% of A. spiraecola (n = 94) specimens in the European samples used for the molecular analysis. The existence of A. spiraecola in the Eastern Baltic region of Europe is documented for the first time. [ABSTRACT FROM AUTHOR]

Nearctic aphid Cinara splendens (Gillette and Palmer, 1924) was collected on ornamental Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) in South Bohemia in 2009. It was the first record of this species in the Palaearctic region. The aim of this research was to study the bionomy of this species in Central Europe and to make descriptions of all available morphs, as previous morphological descriptions of C. splendens appeared to be incomplete. Six monitoring sites of this species were established in South Bohemia and were then regularly attended in the period of 2009–2019. The colonies of C. splendens were observed; its natural enemies and honeydew users were also registered. Aphids were collected for the microscope slide preparation, followed by the evaluation of thirty of the basic quantitative and seven qualitative morphological characteristics. Partial sequences of mitochondrial COI and nuclear EF-1α were used to confirm morphology-based identification and to compare samples from the Czech Republic with those of North American origin. Cinarasplendens survived successfully under new ecological conditions, but its population density remained quite low, except for 2009 and 2019, due to a synergistic effect of the dry weather and very high population density of the adelgid Gilletteella coweni (Gillette, 1907), which is a key pest of Douglas fir in the Czech Republic. The principle predators were coccinellid beetles, while the aphidophagous hover flies were less abundant. Together with a weak ability to migrate due to a low number of alate viviparous females in population, C. splendens cannot be a potential pest of P. menziesii in Central Europe. [ABSTRACT FROM AUTHOR]