Revealing potential bridge vectors for BTV and SBV: a study on Culicoides blood feeding preferences in natural ecosystems in Spain.

Several species of Culicoides (Diptera: Ceratopogonidae) are vectors of pathogens, such as the bluetongue (BTV) and Schmallenberg (SBV) viruses, which cause important diseases in domestic and wild ruminants. As wild ruminants can contribute to overwintering and epizootics of both diseases, knowledge of the host-feeding behaviour of Culicoides in natural ecosystems is important to better understand their epidemiology. Blood-engorged Culicoides females trapped in natural areas inhabited by different wild ruminant species were genetically analysed to identify host species. The origin of bloodmeals was identified in 114 females of 14 species of Culicoides. A total of 104 (91.1%) Culicoides fed on mammals and 10 (8.9%) on birds. The most abundant host identified was red deer (66.7%), followed by humans (13%) and fallow deer (6.1%). Eleven of the 14 species of Culicoides fed exclusively on mammalian hosts. Among them, five are mammalophilic species considered to be important BTV and/or SBV vectors. The results of the present study confirm that Culicoides imicola, Culicoides obsoletus, Culicoides scoticus, Culicoides pulicaris and Culicoides punctatus fed on wild ruminants, and therefore support the hypothesis that these species can act as bridge vectors by facilitating the circulation of pathogens between wild and domestic ruminant communities.

Morphology and DNA barcoding reveal three species in one: description of Culicoides cryptipulicaris sp. nov. and Culicoides quasipulicaris sp. nov. in the subgenus Culicoides.

Species of the genus Culicoides (Diptera: Ceratopogonidae) are well known for their importance in the field of medical and veterinary entomology. Culicoides spp. transmit a wide variety of pathogens, primarily viruses that affect animals and humans. In Europe, the most economically important disease transmitted by Culicoides is bluetongue (BT). Culicoides spp. have been recently involved as primary vectors for Schmallenberg disease. The taxonomy within the subgenus Culicoides has been historically difficult and reorganizations have been proposed regularly. The subgenus Culicoides includes species that are considered to be potential vectors for BT. High morphological intraspecific variability has been attributed to these species. This highlights the apparent presence of previously undetected cryptic species diversity in the subgenus. In the present study, a detailed morphological and molecular study of specimens belonging to Culicoides pulicaris s.l. and specimens resembling a cross between C. pulicaris and Culicoides punctatus revealed the presence of two new species: Culicoides cryptipulicaris and Culicoides quasipulicaris. Females of C. quasipulicaris and males of both species were morphologically distinguished from C. pulicaris (Linnaeus, 1758), whereas females of C. cryptipulicaris were identified using molecular techniques exclusively.

Insulating Carbon Nanotubes by Atomic Layer Deposition for Electrical Wiring Purposes.

Carbon Nanotubes (CNTs) are coated by an insulator (Al2O3) shell using the atomic layer deposition (ALD) technique. This is achieved in large quantities (tens of milligrams per batch) for electrical wiring purposes. Here we present a transmission electron microscopy (TEM) characterization together with a detailed high resolution elemental analysis by in-column energy dispersive X-ray spectroscopy (EDXS). An excellent conformality of the insulator around the CNTs is obtained. Moreover, the elemental maps show the composition of the shell while the line scan analyses demonstrate an abrupt shell-CNT interface achieved by our ALD approach.

Phenotypic differentiation and phylogenetic signal of wing shape in western European biting midges, Culicoides spp., of the subgenus Avaritia.

In the past decade biting midges of the subgenus Avaritia (Diptera: Ceratopogonidae) have been popular subjects of applied entomological studies in Europe owing to their implication as biological vectors in outbreaks of bluetongue and Schmallenberg viruses. This study uses a combination of cytochrome oxidase subunit I barcode sequencing and geometric morphometric analyses to investigate wing shape as a means to infer species identification within this subgenus. In addition the congruence of morphological data with different phylogenetic hypotheses is tested. Five different species of the subgenus Avaritia were considered in the study (C. obsoletus (Meigen); C. scoticus Kettle and Lawson; C. chiopterus (Meigen); C. dewulfi Goetghebuer and C. imicola (Kieffer)). The study demonstrated that over 90% of individuals could be separated correctly into species by their wing shape and that patterns of morphological differentiation derived from the geometric morphometric analyses were congruent with phylogenies generated from sequencing data. Morphological data produced are congruent with monophyly of the subgenus Avaritia and the exclusion of C. dewulfi from the group containing C. obsoletus, C. scoticus and C. chiopterus. The implications of these results and their importance in a wider context of integrating multiple data types to interpret both phylogeny and species characterization is discussed.

Spatio-temporal variation in the structure of a chromosomal polymorphism zone in the house mouse.

Several long-term temporal analyses of the structure of Robertsonian (Rb) hybrid zones in the western house mouse, Mus musculus domesticus, have been performed. Nevertheless, the detection of gradual or very rapid variations in a zone may be overlooked when the time elapsed between periods of study is too long. The Barcelona chromosomal polymorphism zone of the house mouse covers about 5000, km(2) around the city of Barcelona and is surrounded by 40 chromosome telocentric populations. Seven different metacentrics and mice with diploid numbers between 27 and 40 chromosomes and several fusions in heterozygous state (from one to seven) have been reported. We compare the present (period 2008-2010) and past (period 1996-2000) structure of this zone before examining its dynamics in more detail. Results indicate that there is not a Rb race in this area, which is consistent with the proposal that this zone was probably originated in situ, under a primary intergradation scenario. The lack of individuals with more than five metacentrics in heterozygous state in the current period suggests that selection acted against such mice. By contrast, this situation did not occur for mice with fewer than five fusions in heterozygous condition. Changes in human activity may affect the dynamics of gene flow between subpopulations, thus altering the chromosomal composition of certain sites. Although these local variations may have modified the clinal trend for certain metacentrics, the general staggered structure of the zone has not varied significantly in a decade.

Evolutionary modularity of the mouse mandible: dissecting the effect of chromosomal reorganizations and isolation by distance in a Robertsonian system of Mus musculus domesticus.

The mouse mandible consists of several morphogenetic units that are usually grouped into two main modules: the alveolar region and the ascending ramus. The genetic/ontogenetic modularity of the two regions implies that they might evolve independently to some extent. In particular, evolutionary modularity in quantitative traits could arise during chromosomal speciation due to lower gene flow in rearranged chromosomes. With the aim of uncovering the autonomous evolution of the mandible modules, the form variation of each of them was assessed in the house mouse Robertsonian system from Barcelona, in which chromosomal variation and geographical distance may act as isolation factors. The association between these factors and morphological changes was analysed to determine their contribution to the differentiation of each module. Although size changes in the two modules were highly correlated, shape changes were not, and their association with karyotype differences, but not geographical distance, was dependent on the module. The results support the existence of two evolutionary modules and highlight the importance of size in morphological integration of the mandible. They also suggest that geographical distance and chromosomal reorganizations reduce gene flow between karyotypically divergent populations, but although geographical distance represents a global barrier to gene flow, the isolation produced by a set of chromosomal reorganizations only affects particular modules, probably depending on the number and location of loci with effects on a particular morphological region.

Geometric morphometrics of the wing in the subgenus Culicoides (Diptera: Ceratopogonidae): from practical implications to evolutionary interpretations.

Biting midges of the genus Culicoides Latreille have been incriminated in transmission of bluetongue. Since 1998, the disease has spread across Europe provoking the largest epidemic ever recorded with important economic loses. Some species of the subgenus Avaritia and Culicoides have been described as candidate vectors involved in these epizootics. Both subgenera contain groups of cryptic species that could differ in their vectorial capacity. For this reason, the correct identification of vector species is considered an essential issue in epidemiological programs. In the current study, the usefulness of wing form in differentiating morphologically similar species of the subgenus Culicoides by means of geometric morphometric techniques is assessed in specimens previously identified through molecular analyses based on cytochrome oxidase subunit I gene sequences. Significant differences between species were detected in the two components of form, i.e., size and shape. Although wing size was affected by temperature, wing shape showed a more stable specific variation, allowing the proper classification of a high percentage of specimens. In addition, the concordance between phylogenies inferred from molecular data and phenetic clusters suggests the existence of a phylogenetic signal in wing shape. These findings enhance the use of this complex phenotypic trait not only to infer genetic relationships among species of the subgenus Culicoides but also as apotentially powerful tool to differentiate cryptic species within the genus.

Identification of cryptic species of Culicoides (Diptera: Ceratopogonidae) in the subgenus Culicoides and development of species-specific PCR assays based on barcode regions.

Culicoides biting midges (Diptera: Ceratopogonidae) are vectors of important diseases affecting wild and domestic animals. During the last decade they have played a major role in the epidemiology of the largest bluetongue epizootic ever recorded in Europe, the disease is transmitted between hosts almost exclusively by bites of Culicoides midges and affects both domestic and wild ruminants however severe disease usually occurs in certain breeds of sheep and some species of deer. An accurate vector identification is of major importance in arthropod borne diseases surveillance, as great differences in vectorial capacity are found even between close species. Unfortunately, specialized taxonomic knowledge of Culicoides identification is rarely available in routine surveillance, mainly based on wing morphology. Recently, some European species of Culicoides belonging to the subgenus Avaritia Fox, 1955 and Culicoides Latreille, 1809 have been described as new bluetongue virus vectors. In the present study, by using a fragment of the barcode region (COI gene) we report the presence of up to 11 species within the subgenus Culicoides in Catalonia (NE Spain), a region recently affected by a bluetongue epizootic. The molecular analysis revealed new non-described cryptic species which were grouped in three complexes of morphologically similar species, two in the Pulicaris complex resembling Culicoides pulicaris, two in the Fagineus complex resembling Culicoides fagineus and three in the Newsteadi complex resembling Culicoides newsteadi. The phylogenetic relationships among them showed that cryptic species detected in both Pulicaris and Fagineus complexes were closely related, whereas those in the Newsteadi complex were more distant. Accurate analysis of all species using morphological and molecular approaches resulted in the detection of diagnostic metric traits for cryptic species and the design of several new species-specific single and multiplex PCR assays to identify unambiguously all the species, most of them still lacking a specific molecular diagnosis.