Morphological divergence often increases with phylogenetic distance, thus making morphology taxonomically informative. However, transitions to asexual reproduction may complicate this relationship ...because asexual lineages capture and freeze parts of the phenotypic variation of the sexual populations from which they derive. Parasitoid wasps belonging to the genus Lysiphlebus Foerster (Hymenoptera: Braconidae: Aphidiinae) are composed of over 20 species that exploit over a hundred species of aphid hosts, including many important agricultural pests. Within Lysiphlebus, two genetically and morphologically well-defined species groups are recognised: the "fabarum" and the "testaceipes" groups. Yet within each group, sexual as well as asexual lineages occur, and in L. fabarum different morphs of unknown origin and status have been recognised. In this study, we selected a broad sample of specimens from the genus Lysiphlebus to explore the relationship between genetic divergence, reproductive mode and morphological variation in wing size and shape (quantified by geometric morphometrics).
The analyses of mitochondrial and nuclear gene sequences revealed a clear separation between the "testaceipes" and "fabarum" groups of Lysiphlebus, as well as three well-defined phylogenetic lineages within the "fabarum" species group and two lineages within the "testaceipes" group. Divergence in wing shape was concordant with the deep split between the "testaceipes" and "fabarum" species groups, but within groups no clear association between genetic divergence and wing shape variation was observed. On the other hand, we found significant and consistent differences in the shape of the wing between sexual and asexual lineages, even when they were closely related.
Mapping wing shape data onto an independently derived molecular phylogeny of Lysiphlebus revealed an association between genetic and morphological divergence only for the deepest phylogenetic split. In more recently diverged taxa, much of the variation in wing shape was explained by differences between sexual and asexual lineages, suggesting a mechanistic link between wing shape and reproductive mode in these parasitoid wasps.
The main objective of the present paper was to analyse and compare the patterns of molecular and morphological divergence of European parasitoid wasps belonging to the diverse genus
Aphidius
Nees, ...1818. The maximum likelihood and maximum parsimony trees constructed by including 64 different haplotypes of the barcoding region of mitochondrial cytochrome oxidase subunit I (mtCOI) identified for 33
Aphidius
species showed identical topology. A high level (99%) of bootstrap support was found for the phylogenetic line consisting of
A. ribis
Haliday, 1834,
A. chaetosiphonis
Tomanović & Petrović, 2011 and
A. hortensis
Marshall, 1896, and for the group consisting of
A. colemani
Vierck, 1912,
A. transcaspicus
Telenga, 1958,
A. asteris
Haliday, 1834 and
A. platensis
Brethes, 1913
.
The remaining lineages on the trees were not significantly supported. We applied the approach of geometric morphometrics to explore morphological divergences in forewing size. A significant difference of mean wing shape was found between
Aphidius
species. The observed low resolution of the mtCOI gene of morphologically and ecologically well-defined
Aphidius
species is probably due to species hybridisation followed by introgression of mtDNA. Despite low resolution of the phylogenetic tree, the permutation test for a phylogenetic signal in wing shape was statistically significant, indicating that phylogenetically more closely related species are more similar than unrelated ones. A clear agreement between molecular and morphological variation was determined only for the two phylogenetically well-resolved groups.
Dexamethasone is a synthetic glucocorticoid commonly used in both human and veterinary medicine. Prolonged treatment with dexamethasone can lead to serious metabolic side effects such as insulin ...resistance and diabetes. In this study, the morphological, immunohistochemical, and ultrastructural changes in the rat pancreatic islets were investigated after dexamethasone treatment (2 mg/kg, intraperitoneally for 12 days). The results showed that the volume density, mean diameter and profile area of islets were significantly increased in dexamethasone-treated animals. The volume density, profile area and mass of B-cells increased, whereas the volume density of A-and D-cells decreased, as did the number of A-cells per mm 2 of islet. Mild insulin immunopositivity of the centrally located B-cells together with altered ultrastructural features indicated their loss of function. The results of the present study suggest adverse effects of dexamethasone on pancreatic endocrine function that may ultimately seriously affect glucose homeostasis.
In this study, we explored variations in the magnitude and the direction of sexual dimorphism in three parasitoid species from the genus Aphidius Nees (Aphidius balcanicus Tomanović and Petrović, ...Aphidius rosae Haliday, and Aphidius urticae Haliday). We also explored the variation in sexual dimorphism within one of these species, A. urticae, which parasitizes and develops in three different hosts that belong to three aphid genera. To estimate sexual size dimorphism, we selected two developmentally and functionally unrelated morphological structures: the mesoscutum and the wing. Our results showed that sexual dimorphism in mesoscutum and wing size differ (sexual dimorphism in mesoscutum size appears to be insignificant, whereas the wings are larger in males). We found a high level of variation in sexual dimorphism in wing shape within and between species. We also found that the observed shape changes are not due to size-related, allometric changes in wing shape. These results indicate that sexual dimorphism in wing size and wing shape is highly variable and could be influenced by various factors, including host effects, whereas mesoscutum size appears to be a conserved trait in aphid parasitoids.
The genus Praon represents a large group of aphid endoparasitoids and is exemplary for the problems encountered in their taxonomy because of a great variability of morphological characters. To ...investigate the intraspecific variability and to ascertain cryptic speciation within the Praon abjectum Haliday group, biotypes in association with the aphid hosts Aphis sambuci L., Longicaudus trirhodus Walker, and Rhopabsiphum spp. were examined. We combined molecular and geometric morphometric analyses, that is, partial sequences of the mitochondrial cytochrome oxidase subunit I and nuclear 28SD2 genes and the shape of the forewing. Low variation of 28SD2 sequences confirmed the close relatedness of species from the genus Praon. Analysis of the cytochrome oxidase subunit I sequences however identified three separate taxa within the P. abjectum group with substantial genetic divergence. The biotype of P. abjectum associated with L. trirhodus differed from those associated with Rhopabsiphum sp. and A. sambuci by 5.4–6.5% and 7.7% sequence divergence, respectively, while the genetic distance between the latter two biotypes ranged from 9.5 to 10%. The main changes in the forewing shape that discriminate these three biotypes as revealed by geometric morphometrics are related to the stigma shape and the position of the radial nerve. Based on the differences determined in mitochondrial sequences and in the shape of the wing, we describe two new cryptic species within the P. abjectum group as follows: P. sambuci sp. n. in association with A. sambuci/S. nigra and P. longicaudus sp. n. in association with L. trirhodus/T. aquilegifolium.
In this paper, we applied traditional and geometric morphometric methods to analyze variability in wing size and wing shape among species Aphidius absinthi Marshall, A. rosae Haliday and A. urticae ...Haliday. These taxa represent closely related species with different biological and ecological characters. For the morphometric analyses, we used a sample of 52 female specimens that were collected during the period 2009-2013, on different localities in Serbia. Traditional morphometric analyses revealed statistical significance in stigma shape discrimination of analysed taxa. Our geometric morphometric analyses also confirmed that major contribution to the wing shape variation had the changes in length of the radial sector and stigma shape. Combining the traditional and geometric morphometric analyses, we confirmed the validity of the wing characters previously used in taxonomic studies of the genus Aphidius.
Areopraon chaitophori
n. sp. associated with Chaitophorus leucomelas Koch on Populus nigra is described and illustrated. The main diagnostic characters of Areopraon species are discussed, and a key ...for identification of European species is provided. The distal dorsal part of the second metasomal tergite of Areopraon species has a very prominent horizontal longitudinal protuberance which represents a new diagnostic character for Areopraon.
Molecular and morphological variability of Praon dorsale-yomenae species
complex was analyzed using the three independent methods: “traditional”
morphometrics, geometric morphometrics and DNA ...sequence analysis of two gene
regions (COI mtDNA and 28S D2). For morphometric analysis we used 421
specimens (270 females and 151 males) reared from about 30 different species
of aphid hosts throughout Palaearctic. Molecular analysis included 47
specimens in association with different aphid hosts. Discriminant Canonical
Analysis was performed in order to determine which characters were
informative for morphological diferentiation of analyzed taxa. To explore
differences in wing shape between species we performed Canonical Variate
Analysis. Variation in wing shape among biotypes was investigated using
Principal Component Analysis. We found that great variablity in wing shape of
P. dorsale and P. longicorne biotypes was influenced by the host, while great
effect of geographical distribution was noticed between P. yomenae biotypes.
Analysis of wing shape demonstrated that „dorsale-yomenae“ species can be
morphologically discriminated on the basis of length of forewing radial and
recurrent vein. Geometric morphometrics applied to visualize subtle shape
differences had more sensitivity than „traditional“ morphometrics in
distiguishing taxa within „dorsale-yomenae“ group. We tested the validity of
morphological characteristics previously used for identification in
„dorsale-yomenae“ group, also indicating a new characters that could be used
in identification keys. Different colour patterns of wing venation in
„dorsale-yomenae“ species complex were found. On the basis of molecular
results P. longicorne, P. dorsale, P. yomenae and P. volucre was confirmed as
separate species. We presented a new tritrophic association for P. dorsale. A
new parasitoid species from Staticobium limonii infesting Limonium
angustifolium was described. P. megourae was not confirmed as separate
species using molecular markers, thus the clarification of its status
requires further research.
Molekularna i morfološka varijabilnost unutar kompleksa vrsta Praon
dorsale-yomenae analizirana je primenom tri nezavisne metode: “tradicionalne”
morfometrije, geometrijske morfometrije i analize citohrom oksidaza I
sekvenci mitohondrijalne DNK i 28S D2 gena nuklearne DNK. Za morfometrijske
analize korišćena je 421 jedinka (270 ženki i 151 mužjak) sakupljena sa preko
30 različitih afidnih domaćina širom Palearktika. Molekularne analize su
obuhvatile 47 jedinki u asocijaciji sa različitim domaćinima. Primenom
diskriminantne kanonijske analize utvrđeno je koji su karakteri dovoljno
informativni za morfološku diferencijaciju analiziranih taksona. CVA analizom
su prikazane razlike u obliku krila između vrsta. Varijabilnost oblika krila
među biotipovima analizirana je primenom PCA. Pokazano je da postoji značajan
efekat domaćina na varijabilnost oblika krila među biotipovima vrsta P.
dorsale i P. longicorne, dok je među biotipovima vrste P. yomenae utvrđen
značajan efekat geografske distribucije. Analize oblika krila ukazale su na
to da se vrste „dorsale-yomenae“ kompleksa mogu morfološki razlikovati na
osnovu dužine radijalnog i povratnog nerva. Geometrijska morfometrija
primenjena u cilju vizualizacije suptilnih razlika u obliku krila pokazala je
veću osetljivost u razdvajanju analiziranih taksona „dorsale-yomenae“ grupe u
odnosu na „tradicionalnu” morfometriju. Ispitali smo validnost prethodno
korišćenih morfoloških karaktera u identifikaciji „dorsale-yomenae“ grupe.
Takođe smo ukazali na nove karaktere koji se mogu koristiti u ključevima za
identifikaciju. Utvrđeni su različiti obrasci obojenosti krilne nervature
unutar kompleksa vrsta „dorsale-yomenae“. Na osnovu rezultata molekularnih
analiza potvrđen je status vrsta P. longicorne, P. dorsale, P. yomenae i P.
volucre. Utvrđeni su novi domaćini/asocijacije za vrstu P. dorsale. Otkrivena
je nova vrsta za nauku koja parazitira vaš Staticobium limonii na Limonium
angustifolium. Vrsta P. megourae nije dobila molekularnu potvrdu pa su za
rasvetljavanja statusa ovog taksona potrebna dodatna istraživanja.
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