Sibling Species Group Research Articles

Вухань австрійський (Plecotus austriacus) на Волині: новий поступ у експансії на сході Європи

The paper describes the discovery of a species from the group of sibling species of the superspecies Plecotus auritus (sensu lato), which has been showing a wide expansion in Eastern Europe over the past 100 years. Expansion is facilitated by the species’ pronounced synanthropy, with a particular preference for different types of artificial wintering shelters, which often leads to new finds. The new find is the second for the Volyn region of Ukraine and fills the gap between the known finds in Poland, south-western Belarus (Brest region) and neighbouring regions of Ukraine (Lviv and Rivne oblasts). The new find was recorded on 18.09.2021 in the village of Radovychi, Kovel Raion, in a cellar. The currently known finds of the species in the region are distributed fairly evenly in space and time, indicating a slow and wide expansion, without a significant increase in numbers.

The Bemisia tabaci cryptic (sibling) species group -imperative for a taxonomic reassessment.

The taxonomy of the Bemisia tabaci cryptic species group remains a challenge due to the lack of morphological differentiation and porous species boundaries among its members. Additionally, it is unclear whether B. tabaci consists of several species in evolutionary stasis with limited morphological change or is the result of a recent adaptive radiation characterized by great ecological diversity but little morphological divergence. Here, a historical overview of the development of the nomenclature used to classify B. tabaci is provided covering changes after synonymizing several species in 1957 until recent insights gained from whole-genome sequencing data. The article discusses the limitations of using a 3.5% mtCOI threshold and argues that a 1% nuclear divergence cutoff better reflects ecological and biogeographic species boundaries. Finally, a plan of action is outlined for naming B. tabaci species using a Latin binomial system in accordance with the International Comission on Zoological Nomenclature (ICZN) regulations.

Chromosomal polymorphism in natural populations of Chironomus sp. prope agilis Kiknadze, Siirin, Filippova et al., 1991 (Diptera, Chironomidae).

Species Chironomussp.propeagilis Kiknadze, Siirin, Filippova et al., 1991 belongs to the Ch.plumosus group of sibling species. It was described on the basis of its karyotype and analysis of isozymes from one population in the Urals but since then no quantitative data on chromosomal polymorphism of this species have been published. The goal of this study is to broaden our knowledge of the chromosomal polymorphism and distribution of the Chironomussp.propeagilis, which, along with the data on chromosomal polymorphism of other species from the Ch.plumosus group, can give us a better understanding of the connection between chromosomal polymorphism and ecological conditions of habitats. The specimens of Chironomussp.propeagilis were found only in 8 natural populations from the Urals, Western Siberia and Kazakhstan, which allows us to conclude that the species range of Chironomussp.propeagilis is not as wide as for most other species from Ch.plumosus group. An analysis of chromosomal polymorphism in these 8 natural populations of Chironomussp.propeagilis has been performed. All of the studied populations were either monomorphic or showed very low level of chromosomal polymorphism, with 4.4-8.7% of heterozygous specimens per population and 0.04-0.08 heterozygotic inversion per larvae. The total number of banding sequences found in the banding sequence pool of Chironomussp.propeagilis is 10. The mapping of banding sequence p'ag2B3 is presented for the first time. Besides inversions, one reciprocal translocation was found in a population from Kazakhstan, B-chromosome was found in one population from the Urals region of Russia, and heterozygosity of the level of expression of Balbiany rings in arm G was observed in several studied populations.

Karyotype characteristics and gene COI sequences of Chironomusbonus Shilova et Dzhvarsheishvili, 1974 (Diptera, Chironomidae) from the South Caucasus (Republic of Georgia, Paravani river).



A revision of the genus Orchestia Leach, 1814 with the reinstatement of O. inaequalipes (K.H. Barnard, 1951), the designation of a neotype for Orchestia gammarellus (Pallas, 1776) and the description of three new species (Crustacea: Amphipoda: Talitridae: Talitrinae).

The amphipod genus Orchestia is revised. It now includes 10 species of which three are new: O. forchuensis sp. nov. from north-eastern North America and Iceland., O. perezi sp. nov. from Chile and O. tabladoi sp. nov. from Argentina. Orchestia inaequalipes (K.H. Barnard 1951) is reinstated. The type species of the genus, O. gammarellus is redescribed based on material from Fountainstown, Ireland and a neotype is established to stabilize the species. The species was originally described from a garden in Leiden, far from the sea. Its true identity is unknown and no type material exists. Orchestia gammarellus (Pallas, 1776) is shown to be a sibling species group with members in both hemispheres of the temperate Atlantic as well along the Pacific coast of South America. A hypothesis for the establishment of the current distribution of Orchestia species is presented that extends back to the Cretaceous.

Distribution of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Mitotypes in Commercial Cotton Fields in the Punjab Province of Pakistan

The Bemisia tabaci (Gennadius) (Hemiptera: Aleyroridae) sibling species group is comprised of genetic variants defined by biological differences or a fragment of mitochondrial cytochrome oxidase I gene sequence (mitotype) that allows for phylogeographic affiliation. Some mitotypes may cause damage to crop plants by feeding and transmission of plant viruses. In Pakistan, cotton-vegetable agroecosystems are vulnerable to whitefly-transmitted virus (genus Begomovirus; family Geminiviridae) infection. The identity and distribution of the whitefly B. tabaci mitotypes associated with the cotton crop were studied in 8 districts in the Punjab Province from 2014 to 2016. Phylogenetic analysis of the 3ʹ-fragment of the mitochondrial cytochrome oxidase I gene indicated the predominant haplotypes belonged to the Asia II-1 mitotype, with pairwise distances ranging from 0.15 to 3.2%. Pairwise distances showed that B. tabaci haplotype diversity varied by district, with the Khanewal harboring the highest divergence at 1.37%, compared to the lowest at 0.50% in the Dera Ghazi Khan district. The median-joining network analysis showed genetic expansion, or a ‘recovery’ trend, following the declining genetic diversity that occurred during the late 1990s to the early 2000s. The Asia II-1 mitotype group was the predominant whitefly vector species in Punjab Province. The haplotype network provides documentation of continued genetic expansion among the B. tabaci populations in the Punjab, which is consistent with previously reported trends among whiteflies sampled in the same or nearby districts from 2012 to 2014. Genetic expansion varied among districts and could be explained by factors unique to each district, i.e., management practices that influence B. tabaci mitotype composition, whitefly susceptibility to cotton leaf curl disease complex, and cotton genotype Key Words: haplotype; median-joining network analysis; mitochondria cytochrome oxidase I gene; phylogenetic analysis; population genetics Resumen El complejo de moscas blancas Bemisia tabaci (Gennadius) (Hemiptera: Aleyroridae), comprende grupos geneticos cuya afiliacion filo-geografica puede ser determinada mediante una serie de rasgos biologicos o el uso de un fragmento del gen mitocondrial citocromo oxidasa I (mitotipo). Algunos mitotipos de B. tabaci pueden ocasionar danos economicos importantes en cultivos comerciales debido a su alimentacion y a la transmision efectiva de virus vegetales, por ejemplo, en Paquistan, los agro-ecosistemas de algodon son altamente vulnerables a virus transmitidos por moscas blancas (genero Begomovirus; familia Geminiviridae). En este articulo, se estudio la identidad y distribucion geografica de los principales mitotipos de B. tabaci que se encuentran infestando parcelas comerciales de algodon en 8 distritos de la provincia de Punjab, Paquistan, durante los anos 2014-2016. Se determino mediante un analisis filo-genetico del fragmento 3 ʹ del gen citocromo oxidasa I, que el haplotipo mas predominante pertenecio al mitotipo Asia II-1, con distancias geneticas que variaron entre 0.15-3.2%. Se determino que las distancias geneticas entre haplotipos varian por distrito geografico, con la divergencia mas alta de 1.37% en Khanewal, comparado con la divergencia mas baja de 0.50% en el distrito Dera Ghazi Khan. Se demostro mediante un analisis de red de haplotipos, que la poblacion de moscas blancas continua en un proceso de expansion genetica que varia por distrito, lo que coincide con un escenario de expansion demografica reportada en poblaciones de mosca blanca colectadas en localidades similares durante el periodo 2012-2014. El patron geografico de expansion observado puede ser atribuido a factores unicos de cada distrito geografico, por ejemplo: practicas de manejo de plagas que alteren la composicion mitotipica de la mosca blanca, eficiencia del vector para transmitir virus y genotipo de algodon sembrado. Palabras Claves: haplotipo; red de haplotipos median-joining; gen mitocondrial citocromo oxidasa I; analisis filogenetico; genetica de poblaciones View this article in BioOne

Revisiting Seed Transmission of the Type Strain of Tomato yellow leaf curl virus in Tomato Plants

Isolates of the Tomato yellow leaf curl virus (TYLCV) species (genus Begomovirus, family Geminiviridae) infect tomato crops worldwide, causing severe economic damage. Members of the whitefly Bemisia tabaci sibling species group are the vector of begomoviruses, including TYLCV. However, transmission of isolates of the type strain (Israel [IL]) of TYLCV (TYLCV-IL) by tomato seed has recently been reported based on infections occurring in Korea. Because of the consequences of this finding on the epidemiology and control of the disease caused by TYLCV and on the seed market, it was considered essential to revisit and expand those results to other tomato-growing areas. TYLCV DNA content was detected in tomato and Nicotiana benthamiana seed collected from plants naturally or experimentally infected with TYLCV-IL, supporting its seedborne nature. The TYLCV-IL replication detected in tomato and N. benthamiana flower reproductive organs demonstrated close association of this virus with the seed during maturation. However, the significant reduction of TYLCV DNA load after surface disinfections of tomato seed suggests that most of the virus is located externally, as contaminant of the seed coat. Transmission assays, carried out with seven tomato genotypes and more than 3,000 tomato plants, revealed no evidence of seed transmission from "surface-disinfected" or untreated seed for two Mediterranean isolates of TYLCV-IL. Similar results were also obtained for seed collected from TYLCV-IL-infected N. benthamiana plants. The results support the conclusion that TYLCV-IL is seedborne but is not seed transmitted in tomato or N. benthamiana, suggesting that transmission through seed is not a general property of TYLCV.

Geographic and Ecological Dimensions of Host Plant-Associated Genetic Differentiation and Speciation in the Rhagoletis cingulata (Diptera: Tephritidae) Sibling Species Group.

Ascertaining the causes of adaptive radiation is central to understanding how new species arise and come to vary with their resources. The ecological theory posits adaptive radiation via divergent natural selection associated with novel resource use; an alternative suggests character displacement following speciation in allopatry and then secondary contact of reproductively isolated but ecologically similar species. Discriminating between hypotheses, therefore, requires the establishment of a key role for ecological diversification in initiating speciation versus a secondary role in facilitating co-existence. Here, we characterize patterns of genetic variation and postzygotic reproductive isolation for tephritid fruit flies in the Rhagoletis cingulata sibling species group to assess the significance of ecology, geography, and non-adaptive processes for their divergence. Our results support the ecological theory: no evidence for intrinsic postzygotic reproductive isolation was found between two populations of allopatric species, while nuclear-encoded microsatellites implied strong ecologically based reproductive isolation among sympatric species infesting different host plants. Analysis of mitochondrial DNA suggested, however, that cytoplasmic-related reproductive isolation may also exist between two geographically isolated populations within R cingulata. Thus, ecology associated with sympatric host shifts and cytoplasmic effects possibly associated with an endosymbiont may be the key initial drivers of the radiation of the R. cingulata group.

The identity of some specimens previously (mis)identified as Rhinoleucophenga obesa (Loew) (Diptera: Drosophilidae) in Brazil, based on morphological and molecular data, with implications on distribution.

Rhinoleucophenga Hendel is an endemic genus of the New World with most species recorded in Brazil. Rhinoleucophenga obesa (Loew) seemed to be the most widespread species, being recorded in the United States of America, Mexico and Brazil. In the Neotropical region, identifications of R. obesa were commonly based on the description of non-type specimens determined by Costa Lima (1935) and Malogolowkin (1946), although their identities were doubtful. However, the recent redescription of R. obesa from the type-series from Texas, USA, confirmed a long period of misidentifications and a new species, R. cantareira Vilela Bächli, was proposed based on Brazilian specimens. Thus, review of morphological and molecular traits of specimens previously identified as R. obesa in Neotropical biomes are necessary to check the identity and distribution of a group of sibling species: R. obesa, R. cantareira, R. gigantea (Thomson), R. pallida Hendel and R. pampeana Poppe et al. In the present paper, specimens previously determined as R. obesa, sampled in different Brazilian localities, were compared by morphological and molecular traits. Plates of female terminalia of R. cantareira and R. gigantea are presented for the first time. The spermathecal capsules (as well as the male epandrium) revealed useful characteristics to differentiate those species; these morphological differences were corroborated by a sequence fragment of COI. The specimens on which were based the descriptions of Rhinoleucophenga obesa sensu Costa Lima (1935) and sensu Malogolowkin (1946) were reviewed and confirmed as R. cantareira. Other Brazilian specimens from different localities, previously misidentified as R. obesa, were determined as R. gigantea or R. cantareira, with new records for both species. Therefore, the present study corresponds to the advance of identity definition and distribution of sibling species of Rhinoleucophenga commonly sampled in Neotropical inventory studies.

In search of speciation: Diversification of Stuckenia pectinata s.l. (Potamogetonaceae) in southern Siberia (Asian Russia)

Although aquatic plants usually are less taxonomically diverse than related terrestrial groups, genetic studies could reveal groups of sibling species and thus increase taxonomic resolution. We hypothesised that different age and environmental diversity of water bodies in southern Siberia caused diversification within Stuckenia pectinata s.l. (Potamogetonaceae). To test this hypothesis we studied nuclear (ITS) and plastid (rpl32-trnL) genetic variation of 37 populations of S. pectinata from eastern Europe, the Russian Far East and southern Siberia with special emphasis on the latter. Plastid DNA variability within S. pectinata s.l. was found to be structured neither geographically nor taxonomically. We revealed strong ITS differentiation within S. pectinata s.l. in southern Siberian water bodies with different combinations of age and salinity. We discuss possible causes of such differentiation. We found a striking contrast between the absence of ITS variability across almost all of Europe colonized by the only ribotype, and relatively high ITS variability in southern Siberia. This contrast could be explained by the different history of young European populations that could have appeared as a result of recent northwards expansion following the Last Glacial Maximum, and the relatively old ones of southern Siberia. The absence of clear correspondence between genetic variation and morphological variability does not sufficiently support delimitation of species within Siberian S. pectinata s.l. (such as S. chakassiensis and S. macrocarpa).

Old World-New World differentiation of so-called “circumtropical” taxa: the case of rare genus Grimaldina Richard, 1892 (Branchiopoda: Cladocera: Macrothricidae)

The Cladocera (Crustacea: Branchiopoda) is an ancient group of predominantly freshwater microscopic invertebrates. During the last three decades a cosmopolitanism paradigm in the biogeography of these animals is gradually being replaced by a concept of continental endemism. Current morphological and molecular genetic data demonstrate that many Holarctic taxa actually represent sibling species groups with localized distributions. Similarly, some circumtropical cladocerans are poorly studied and must be considered using the same concept. Grimaldina Richard, 1892 (Cladocera: Macrothricidae) is an example of such taxon. Since the first description time, this genus was considered as monotypic, including a single species Grimaldina brazzai Richard, 1892, distributed in tropical regions all around the World, but being rare everywhere across its distribution range. We carefully examined specimens of Grimaldina from different tropical water bodies, redescribed morphology of G. brazzai based on new material from Africa, supplemented the genus diagnosis, and demonstrated that G. brazzai is limited to the Old World (Africa and Asia). Population from New World tropical regions are described as Grimaldina freyi sp. nov., based on material from the collection of Prof. Dr David G. Frey and named in his honor. It clearly differs from G. brazzai in: (1) antenna II with longest endopod seta bearing more densely set spinulae and (2) limb V medial portion with a smaller ratio of seta 2 to seta 3. These traits in G. freyi sp. nov. are presumably plesiomorphic, while G. brazzai has more apomorphies. Divergence between American (G. freyi sp. nov.) and Old World (G. brazzai) populations could be related to the ancient vicariant events (Gondwana breakup) or to more recent trans-continental dispersal events.

Global Population Structure of a Worldwide Pest and Virus Vector: Genetic Diversity and Population History of the Bemisia tabaci Sibling Species Group.

The whitefly Bemisia tabaci sibling species (sibsp.) group comprises morphologically indiscernible lineages of well-known exemplars referred to as biotypes. It is distributed throughout tropical and subtropical latitudes and includes the contemporary invasive haplotypes, termed B and Q. Several well-studied B. tabaci biotypes exhibit ecological and biological diversity, however, most members are poorly studied or completely uncharacterized. Genetic studies have revealed substantial diversity within the group based on a fragment of the mitochondrial cytochrome oxidase I (mtCOI) sequence (haplotypes), with other tested markers being less useful for deep phylogenetic comparisons. The view of global relationships within the B. tabaci sibsp. group is largely derived from this single marker, making assessment of gene flow and genetic structure difficult at the population level. Here, the population structure was explored for B. tabaci in a global context using nuclear data from variable microsatellite markers. Worldwide collections were examined representing most of the available diversity, including known monophagous, polyphagous, invasive, and indigenous haplotypes. Well-characterized biotypes and other related geographic lineages discovered represented highly differentiated genetic clusters with little or no evidence of gene flow. The invasive B and Q biotypes exhibited moderate to high levels of genetic diversity, suggesting that they stemmed from large founding populations that have maintained ancestral variation, despite homogenizing effects, possibly due to human-mediated among-population gene flow. Results of the microsatellite analyses are in general agreement with published mtCOI phylogenies; however, notable conflicts exist between the nuclear and mitochondrial relationships, highlighting the need for a multifaceted approach to delineate the evolutionary history of the group. This study supports the hypothesis that the extant B. tabaci sibsp. group contains ancient genetic entities and highlights the vast cryptic diversity throughout the genome in the group.

Transcriptomic differences between euryhaline and stenohaline malaria vector sibling species in response to salinity stress.

Evolution of osmoregulatory systems is a key factor in the transition of species between fresh- and saltwater habitats. Anopheles coluzzii and Anopheles merus are stenohaline and euryhaline malaria vector mosquitoes belonging to a larger group of sibling species, the Anopheles gambiae complex, which radiated in Africa within the last 2 million years. Comparative ecological genomics of these vector species can provide insight into the mechanisms that permitted the rapid radiation of this species complex into habitats of contrasting salinity. Here, we use RNA-Seq to investigate gene expression differences between An.coluzzii and An.merus after briefly exposing both young and old larval instars of each species to either saltwater (SW) or freshwater (FW). Our study aims to identify candidate genes and pathways responsible for the greater SW tolerance of An.merus. Our results are congruent with the ability of gene induction to mediate salinity tolerance, with both species showing increasing amounts of differential gene expression between SW and FW as salt concentrations increase. Besides ion transporters such as AgAE2 that may serve as effectors for osmoregulation, we also find mitogen-activated protein kinases that may serve in a phosphorylation signalling pathway responding to salinity, and report potential cross-talk between the mosquito immune response and osmoregulation. This study provides a key step towards applying the growing molecular knowledge of these malaria vectors to improve understanding of their ecological tolerances and habitat occupancy.

Description of a new species of rabbitfish (Perciformes: Siganidae) from southern India, Sri Lanka and the Maldives.

Siganus insomnis sp. nov. is described from the Maldives, Sri Lanka and southern India. It most closely resembles S. lineatus (Valenciennes) from the Western Pacific but differs in coloration, principally in that most if not all of the bronze bands on its mid and upper sides continue horizontally and unbroken through to the nape and opercular slit. By contrast, in S. lineatus, typically the anterior area below the spinous dorsal fin down to the mid-sides is irregularly marked with golden bronze spots, commas, or a maze of contorted lines. S. guttatus (Bloch) is the third member of this group of sibling species; its sides are covered with orange to bronze-gold spots. It is distributed throughout S.E. Asia, i.e., it occupies a geographic position between the areas inhabited by S. lineatus and S. insomnis. Thus the gene pools of S. lineatus and S. insomnis are quarantined from one another by distance and the intervening presence of S. guttatus in S.E. Asia. The geographical separation of the populations of S. lineatus and S. insomnis from one another is reinforced by the absence of suitable, coralline habitats for these species in the western half of the Bay of Bengal.

DNA barcoding of marine copepods: assessment of analytical approaches to species identification.

More than 2,500 species of copepods (Class Maxillopoda; Subclass Copepoda) occur in the marine planktonic environment. The exceptional morphological conservation of the group, with numerous sibling species groups, makes the identification of species challenging, even for expert taxonomists. Molecular approaches to species identification have allowed rapid detection, discrimination, and identification of species based on DNA sequencing of single specimens and environmental samples. Despite the recent development of diverse genetic and genomic markers, the barcode region of the mitochondrial cytochrome c oxidase subunit I (COI) gene remains a useful and – in some cases – unequaled diagnostic character for species-level identification of copepods. This study reports 800 new barcode sequences for 63 copepod species not included in any previous study and examines the reliability and resolution of diverse statistical approaches to species identification based upon a dataset of 1,381 barcode sequences for 195 copepod species. We explore the impact of missing data (i.e., species not represented in the barcode database) on the accuracy and reliability of species identifications. Among the tested approaches, the best close match analysis resulted in accurate identification of all individuals to species, with no errors (false positives), and out-performed automated tree-based or BLAST based analyses. This comparative analysis yields new understanding of the strengths and weaknesses of DNA barcoding and confirms the value of DNA barcodes for species identification of copepods, including both individual specimens and bulk samples. Continued integrative morphological-molecular taxonomic analysis is needed to produce a taxonomically-comprehensive database of barcode sequences for all species of marine copepods.

Phylogenetic reconstruction and DNA barcoding for closely related pine moth species (Dendrolimus) in China with multiple gene markers.

Unlike distinct species, closely related species offer a great challenge for phylogeny reconstruction and species identification with DNA barcoding due to their often overlapping genetic variation. We tested a sibling species group of pine moth pests in China with a standard cytochrome c oxidase subunit I (COI) gene and two alternative internal transcribed spacer (ITS) genes (ITS1 and ITS2). Five different phylogenetic/DNA barcoding analysis methods (Maximum likelihood (ML)/Neighbor-joining (NJ), “best close match” (BCM), Minimum distance (MD), and BP-based method (BP)), representing commonly used methodology (tree-based and non-tree based) in the field, were applied to both single-gene and multiple-gene analyses. Our results demonstrated clear reciprocal species monophyly for three relatively distant related species, Dendrolimus superans, D. houi, D. kikuchii, as recovered by both single and multiple genes while the phylogenetic relationship of three closely related species, D. punctatus, D. tabulaeformis, D. spectabilis, could not be resolved with the traditional tree-building methods. Additionally, we find the standard COI barcode outperforms two nuclear ITS genes, whatever the methods used. On average, the COI barcode achieved a success rate of 94.10–97.40%, while ITS1 and ITS2 obtained a success rate of 64.70–81.60%, indicating ITS genes are less suitable for species identification in this case. We propose the use of an overall success rate of species identification that takes both sequencing success and assignation success into account, since species identification success rates with multiple-gene barcoding system were generally overestimated, especially by tree-based methods, where only successfully sequenced DNA sequences were used to construct a phylogenetic tree. Non-tree based methods, such as MD, BCM, and BP approaches, presented advantages over tree-based methods by reporting the overall success rates with statistical significance. In addition, our results indicate that the most closely related species D. punctatus, D. tabulaeformis, and D. spectabilis, may be still in the process of incomplete lineage sorting, with occasional hybridizations occurring among them.

Anopheles (Cellia) rampae n. sp., alias chromosomal form K of the Oriental Maculatus Group (Diptera: Culicidae) in Southeast Asia

Chromosomal form K (also known as species K) of the Anopheles maculatus group of sibling species in the Oriental Region is diagnosed and formally named An. (Cellia) rampae Harbach & Somboon, n. sp. The male genitalia, pupa and fourth-instar larva are illustrated and information is provided on the morphology, systematics, bionomics and distribution of the species.

Functional Anatomy of Whitefly Organs Associated with Squash Leaf Curl Virus (Geminiviridae: Begomovirus) Transmission by the B Biotype of Bemisia tabaci (Hemiptera: Aleyrodidae)

Abstract The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is a sibling species group that transmits Squash leaf curl virus (SLCV) and other geminiviruses (Geminiviridae, genus Begomovirus) in a circulative and persistent manner. Using in situ hybridization, SLCV was localized in the primary salivary glands, the midgut, and the filter chamber of adults of the B biotype in the group. However, no SLCV particles were localized in the accessory salivary glands. The midgut loop was found to reside, fully or partially, in the abdomen or thorax in >8,000 dissections, indicating that it is capable of moving through the petiole, a constriction between the two body sections. When extended to its anterior-most position in the thorax, the midgut can make direct contact with the salivary glands, but evidence for direct transfer of virions is lacking. However, the widely presumed pathway of viral transport from the gut to the whitefly primary salivary glands can now be broadened to include both the blood and the possibility of direct transfer during contiguity of these two organs. Light microscopical observations indicated that the primary salivary gland consists of a central region flanked by two dark-staining regions, referred to as endcaps. Electron microscopical examination of extirpated and nonextirpated primary salivary glands revealed additional distinct regions and cell types. One such region, located between the central region and an endcap, was correlated directly to the region where virions have previously been immunolocalized.

Upslope movements and large scale expansions: the taxonomy and biogeography of the Coenonympha arcania -C. d arwiniana -C. gardetta butterfly species complex

Sibling species groups are suitable models for the understanding of inter- and intraspecific processes in taxonomy and biogeography. We analysed 262 individuals from the Alps of the Coenonympha arcania/gardetta species complex by allozyme electrophoresis. These taxa showed high variance amongst populations (FST: 0.391) and strong intertaxon genetic differentiation (FCT: 0.376). Although morphologically similar, Coenonympha gardetta and Coenonympha arcania clearly differ in their genetic characteristics; the morphologically intermediate taxa Coenonympha darwiniana darwiniana and Coenonympha darwiniana macromma are genetically well distinguished from each other and the two other taxa. Coenonympha arcania and C. d. macromma most probably share a common ancestor and evolved by cladogenesis, whereas the taxonomic situation of C. d. macromma is still unresolved: This taxon might be the result of hybridization between C. arcania and C. gardetta or it might have a common ancestor together with C. gardetta. We suggest species rank for all four taxa. The distribution of genetic diversity of these populations and the differentiation amongst populations suggest rather different biogeographical scenarios: C. arcania most probably is of Mediterranean origin with postglacial range expansion northwards; C. gardetta survived the last ice age in peripheral refugia of the Alps and has spread all over this high mountain system in the postglacial; C. darwiniana and C. macromma survived the Würm in geographic proximity to their actual distribution areas and only have performed moderate uphill translocations during postglacial warming.

Taxonomy of the Genus Isophya (Orthoptera, Phaneropteridae, Barbitistinae): Comparison of Karyological and Morphological Data

The genus Isophya represents one of the largest orthopteran genera with about 45 species occurring in Europe. All over its range the genus includes groups of sibling species, the recognition of which is hampered by their morphological similarity. In part, some species were grouped according to their morphology: the Isophya straubei-group, the I. amplipennis-group and the I. major-group. Nevertheless, many species have not been studied using new methods. This is particularly true for 15 taxa described from the Balkans, more or less resembling I. modesta, known mostly from old, unsatisfactorily informative descriptions. Chromosomal analysis of 25 species/subspecies of the genus Isophya showed the karyotypic evolution among species. The karyotype of 18 species/subspecies was investigated for the first time. The most remarkable changes in the sex chromosomes were the ancient acrocentric X chromosome inversions in 19 species and an X chromosome/autosome mutual tandem translocation, from which the sex determination system neo-XY originated in I. hemiptera. Karyotype differentiation has been less rapid in autosomes than in sex chromosomes, in this case interspecific autosomal differentiation has involved the distribution and quantity of C-heterochromatin as well as the number of NORs. Cytogenetic analysis revealed some changes reflecting the level of genomic organization, and the results suggest some association of related taxa from biogeographic regions.