A window on remarkable cryptic diversity of the Merodon planifacies subgroup (Diptera: Syrphidae) in the Afrotropical Region.

The genus Merodon Meigen (Diptera: Syrphidae) is one of the most species-rich hoverfly genera distributed across the Palaearctic and Afrotropical regions. In the Palaearctic, the genus Merodon boasts 195 described species, while its Afrotropical region pales in comparison, with a mere 17 species documented thus far. As a result of 8 years of fieldwork conducted in the Republic of South Africa, in this paper, we present the description of 11 new species for science with a description of immature stages for 2 species, which increases the diversity of this genus in the Afrotropical region by remarkable 39%. These revelations are based on integrating morphology, molecular analysis (COI gene and 28S rRNA) and geometric morphometry. All described species belong to the Merodon planifacies subgroup, the Merodon desuturinus lineage and, within that, to the Afrotropical Merodon melanocerus group. Additionally, we provide an illustrated key to 15 species belonging to the subgroup, a detailed discussion on relevant taxonomic characters, a morphological diagnosis, a distribution map and clarification of the association between M. capi complex and host plants from the genus Merwilla.

The phylogeny and evolutionary ecology of hoverflies (Diptera: Syrphidae) inferred from mitochondrial genomes.

Hoverflies (Diptera: Syrphidae) are a diverse group of pollinators and a major research focus in ecology, but their phylogenetic relationships remain incompletely known. Using a genome skimming approach we generated mitochondrial genomes for 91 species, capturing a wide taxonomic diversity of the family. To reduce the required amount of input DNA and overall cost of the library construction, sequencing and assembly was conducted on mixtures of specimens, which raises the problem of chimera formation of mitogenomes. We present a novel chimera detection test based on gene tree incongruence, but identified only a single mitogenome of chimeric origin. Together with existing data for a final set of 127 taxa, phylogenetic analysis on nucleotide and amino acid sequences using Maximum Likelihood and Bayesian Inference revealed a basal split of Microdontinae from all other syrphids. The remainder consists of several deep clades assigned to the subfamily Eristalinae in the current classification, including a clade comprising the subfamily Syrphinae (plus Pipizinae). These findings call for a re-definition of subfamilies, but basal nodes had insufficient support to fully justify such action. Molecular-clock dating placed the origin of the Syrphidae crown group in the mid-Cretaceous while the Eristalinae-Syrphinae clade likely originated near the K/Pg boundary. Transformation of larval life history characters on the tree suggests that Syrphidae initially had sap feeding larvae, which diversified greatly in diet and habitat association during the Eocene and Oligocene, coinciding with the diversification of angiosperms and the evolution of various insect groups used as larval host, prey, or mimicry models. Mitogenomes proved to be a powerful phylogenetic marker for studies of Syrphidae at subfamily and tribe levels, allowing dense taxon sampling that provided insight into the great ecological diversity and rapid evolution of larval life history traits of the hoverflies.

First mitochondrial genomes of five hoverfly species of the genus Eristalinus (Diptera: Syrphidae).

The hoverfly genus Eristalinus (Diptera, Syrphidae) contains many widespread pollinators. The majority of the species of Eristalinus occur in the Afrotropics and their molecular systematics still needs to be investigated. This study presents the first complete and annotated mitochondrial genomes for five species of Eristalinus. They were obtained by high-throughput sequencing of total genomic DNA. The total length of the mitogenomes varied between 15 757 and 16 245 base pairs. Gene composition, positions, and orientation were shared across species, and were identical to those observed for other Diptera. Phylogenetic analyses (maximum likelihood and Bayesian inference) based on the 13 protein coding and both rRNA genes suggested that the subgenus Eristalinus was paraphyletic with respect to the subgenus Eristalodes. An analysis of the phylogenetic informativeness of all protein coding and rRNA genes suggested that NADH dehydrogenase subunit 5 (nad5), cytochrome c oxidase subunit 1, nad4, nad2, cytochrome b, and 16S rRNA genes are the most promising mitochondrial molecular markers to result in supported phylogenetic hypotheses of the genus. In addition to the five complete mitogenomes currently available for hoverflies, the five mitogenomes published here will be useful for broader molecular phylogenetic analyses among hoverflies.

Ethiopian muscids (Diptera, Muscidae) egg-carriers of Stylogaster Macquart (Diptera, Conopidae).

We here report for the first time on the presence of three species of the conopid genus Stylogaster Macquart (Diptera, Conopidae) in Ethiopia, viz. S. nitens Brunetti, S. westwoodi Smith and Stylogaster sp.. We further screened 908 muscid flies (Diptera, Muscidae) for the presence of impaled eggs of Stylogaster and recorded eggs on 89 individuals (9.8%). Eggs were impaled on eight species, viz. Limnophora translucida Stein, Musca lusoria Wiedemann, Musca splendens Pont, Neomyia chrysopyga (Emden), Pseudohelina nigritarsis (Jaennicke), Stomoxys omega Newstead, Stomoxys taeniatus Bigot and Stomoxys varipes (Bezzi). The maximum number of eggs found on a single muscid was six. We illustrated the dissected eggs. L. translucida, M. lusoria, M. splendens, N. chrysopyga and S. varipes are reported as new muscid hosts species for Stylogaster.

Anchored enrichment dataset for true flies (order Diptera) reveals insights into the phylogeny of flower flies (family Syrphidae).

BACKGROUND: Anchored hybrid enrichment is a form of next-generation sequencing that uses oligonucleotide probes to target conserved regions of the genome flanked by less conserved regions in order to acquire data useful for phylogenetic inference from a broad range of taxa. Once a probe kit is developed, anchored hybrid enrichment is superior to traditional PCR-based Sanger sequencing in terms of both the amount of genomic data that can be recovered and effective cost. Due to their incredibly diverse nature, importance as pollinators, and historical instability with regard to subfamilial and tribal classification, Syrphidae (flower flies or hoverflies) are an ideal candidate for anchored hybrid enrichment-based phylogenetics, especially since recent molecular phylogenies of the syrphids using only a few markers have resulted in highly unresolved topologies. Over 6200 syrphids are currently known and uncovering their phylogeny will help us to understand how these species have diversified, providing insight into an array of ecological processes, from the development of adult mimicry, the origin of adult migration, to pollination patterns and the evolution of larval resource utilization. RESULTS: We present the first use of anchored hybrid enrichment in insect phylogenetics on a dataset containing 30 flower fly species from across all four subfamilies and 11 tribes out of 15. To produce a phylogenetic hypothesis, 559 loci were sampled to produce a final dataset containing 217,702 sites. We recovered a well resolved topology with bootstrap support values that were almost universally >95 %. The subfamily Eristalinae is recovered as paraphyletic, with the strongest support for this hypothesis to date. The ant predators in the Microdontinae are sister to all other syrphids. Syrphinae and Pipizinae are monophyletic and sister to each other. Larval predation on soft-bodied hemipterans evolved only once in this family. CONCLUSIONS: Anchored hybrid enrichment was successful in producing a robustly supported phylogenetic hypothesis for the syrphids. Subfamilial reconstruction is concordant with recent phylogenetic hypotheses, but with much higher support values. With the newly designed probe kit this analysis could be rapidly expanded with further sampling, opening the door to more comprehensive analyses targeting problem areas in syrphid phylogenetics and ecology.

Higher phylogeny of frugivorous flies (Diptera, Tephritidae, Dacini): localised partition conflicts and a novel generic classification.

The phylogenetic relationships within and among subtribes of the fruit fly tribe Dacini (Ceratitidina, Dacina, Gastrozonina) were investigated by sequencing four mitochondrial and one nuclear gene fragment. Bayesian, maximum likelihood and maximum parsimony analyses were implemented on two datasets. The first, aiming at obtaining the strongest phylogenetic signal (yet, having lower taxon coverage), consisted of 98 vouchers and 2338 concatenated base pairs (bp). The second, aiming at obtaining the largest taxonomic coverage (yet, providing lower resolution), included 159 vouchers and 1200 concatenated bp. Phylogenetic relationships inferred by different tree reconstruction methods were largely congruent and showed a general agreement between concatenated tree topologies. Yet, local conflicts in phylogenetic signals evidenced a number of critical sectors in the phylogeny of Dacini fruit flies. All three Dacini subtribes were recovered as monophyletic. Yet, within the subtribe Ceratitidina only Perilampsis and Capparimyia formed well-resolved monophyletic groups while Ceratitis and Trirhithrum did not. Carpophthoromyia was paraphyletic because it included Trirhithrum demeyeri and Ceratitis connexa. Complex phylogenetic relationships and localised conflict in phylogenetic signals were observed within subtribe Dacina with (a) Dacus, (b) Bactrocera (Zeugodacus) and (c) all other Bactrocera species forming separate clades. The subgenus Bactrocera (Zeugodacus) is therefore raised to generic rank (Zeugodacus Hendel stat. nov.). Additionally, Bactrocera subgenera grouped under the Zeugodacus group should be considered under new generic combinations. Although there are indications that Zeugodacus and Dacus are sister groups, the exact relationship between Zeugodacus stat. nov., Dacus and Bactrocera still needs to be properly resolved.

Insertion sequence element single nucleotide polymorphism typing provides insights into the population structure and evolution of Mycobacterium ulcerans across Africa.

Buruli ulcer is an indolent, slowly progressing necrotizing disease of the skin caused by infection with Mycobacterium ulcerans. In the present study, we applied a redesigned technique to a vast panel of M. ulcerans disease isolates and clinical samples originating from multiple African disease foci in order to (i) gain fundamental insights into the population structure and evolutionary history of the pathogen and (ii) disentangle the phylogeographic relationships within the genetically conserved cluster of African M. ulcerans. Our analyses identified 23 different African insertion sequence element single nucleotide polymorphism (ISE-SNP) types that dominate in different areas where Buruli ulcer is endemic. These ISE-SNP types appear to be the initial stages of clonal diversification from a common, possibly ancestral ISE-SNP type. ISE-SNP types were found unevenly distributed over the greater West African hydrological drainage basins. Our findings suggest that geographical barriers bordering the basins to some extent prevented bacterial gene flow between basins and that this resulted in independent focal transmission clusters associated with the hydrological drainage areas. Different phylogenetic methods yielded two well-supported sister clades within the African ISE-SNP types. The ISE-SNP types from the "pan-African clade" were found to be widespread throughout Africa, while the ISE-SNP types of the "Gabonese/Cameroonian clade" were much rarer and found in a more restricted area, which suggested that the latter clade evolved more recently. Additionally, the Gabonese/Cameroonian clade was found to form a strongly supported monophyletic group with Papua New Guinean ISE-SNP type 8, which is unrelated to other Southeast Asian ISE-SNP types.

Predominance of a single phylogenetic species in colonization events among a sextet of decollate land snail, Rumina decollata (Mollusca: Pulmonata: Subulinidae), species.

The hermaphroditic, facultatively selfing, land snail Rumina decollata is a common, widespread species that is indigenous to the Mediterranean region and that has been introduced to many other regions of the world. However, recent DNA sequence analyses have indicated that R. decollata is a complex of several phylogenetic species, two of which correspond to previously distinguished allozyme strains with different body colors (light vs. dark) and life history characteristics. Against this background, this paper attempts to identify which of these phylogenetic species have been introduced elsewhere in the world. Based on a comparative DNA sequence analysis of putatively introduced populations from South America, North America, Japan, and the North Atlantic Islands versus native Mediterranean populations, it is shown that all putatively introduced populations belong to a single phylogenetic species that was previously recognized as the dark morph. Hence, the colonizing and invasive character of R. decollata seems to be due to this phylogenetic species. Nevertheless, in its native area the dark morph is supposed to be outcompeted when sympatric with the light morph of R. decollata. This issue is briefly discussed and the Iberian Peninsula is tentatively proposed as an important source for introduced R. decollata populations outside Europe.

Taxonomic and population genetic re-interpretation of two color morphs of the decollate snail, Rumina decollata (Mollusca, Pulmonata) in southern France.

The hermaphroditic terrestrial snail Rumina decollata has a mixed breeding system with a high prevalence of self-fertilization. In the Montpellier area (France), the species is represented by a dark and a light color morph. Based on allozyme data, both morphs have been reported as single, homozygous multilocus genotypes (MLG), differing at 13 out of 26 loci, but still showing occasional hybridization. Recent DNA sequence data suggest that each morph is a different phylogenetic species. In order to further evaluate this new taxonomic interpretation, the present contribution explores to what extent populations or color morphs indeed consist of single or few MLG. As such it is shown that both morphs are not single, homozygous MLG, but instead reveal a considerable amount of allelic variation and substantial numbers of heterozygous microsatellite genotypes. This suggests that outcrossing may be more prevalent than previously reported. Nevertheless, both morphs maintain a diagnostic multimarker differentiation in the presence of outcrossing in sympatric conditions, implying that they may be interpreted as species under the biological species concept. Finally, our data challenge the idea that simultaneous hermaphrodites should be either strict selfers or strict outcrossers.

Identification of forensically important Sarcophaga species (Diptera: Sarcophagidae) using the mitochondrial COI gene.

The identification of species of the forensically important genus Sarcophaga is very difficult and requires strong taxonomic expertise. In this study, we sequenced the mitochondrial cytochrome c oxidase subunit I (COI) gene of 126 specimens of 56 W European Sarcophaga species and added GenBank data to our database to yield a total dataset of 270 COI sequences from 99 Sarcophaga species to evaluate the COI gene as a molecular diagnostic tool for species identification in this genus. Using two simple criteria (Best Match, BM and Best Close Match, BCM), we showed that the identification success using a mini-barcode region of 127 bp was very low (80.7-82.5 %) and the use of this region is not recommended as a species identifier. In contrast, identification success was very high using the standard barcode region (658 bp) or using the entire COI region (1,535 bp) (98.2-99.3 %). Yet, there was a low interspecific sequence divergence (<2 %) in six species groups so that for 16 out of the 99 species (nine of which are of forensic importance), the use of COI barcodes as species identifier should be done with care. For these species, additional markers will be necessary to achieve a 100 % identification success. We further illustrate how such reference databases can improve local reference databases for forensic entomologists.

Mixed breeding system in the hermaphroditic land slug Arion intermedius (Stylommatophora, Arionidae).

Theory suggests that hermaphroditic plants and animals should be either entirely outcrossing or entirely selfing. As such, very few hermaphroditic plants and basommatophoran snails have a mixed breeding system. However, reliable estimates of selfing rates are lacking for most hermaphroditic animals. This partly prevents to delineate the relative contributions of the selective factors that determine selfing and outcrossing rates in hermaphroditic animal taxa. Here, we studied the population genetic structure of, and breeding system in, 11 populations of the hermaphroditic land slug Arion intermedius using five polymorphic microsatellite loci. Moreover, genotype frequencies deviated significantly from Hardy-Weinberg equilibrium expectations for most of the loci in all populations suggesting some level of selfing. Estimates of the selfing level s, suggest moderate levels of outcrossing (mean s based on FIS = 0.84; mean s based on the two-locus heterozygosity disequilibrium = 0.20, or with a ML approach = 0.22). Our study therefore suggests that A. intermedius has a mixed breeding system. A re-analysis of allozyme data from another arionid slug ( subgenus Carinarion) indicates that mixed breeding may be more common in arionid slugs than hitherto was assumed. These results seem therefore at variance with current theoretical and empirical predictions and opens perspectives for the study on the evolutionary factors driving mixed breeding systems in animals.

Cold tolerance and freeze-induced glucose accumulation in three terrestrial slugs.

Cold tolerance and metabolic responses to freezing of three slug species common in Scandinavia (Arion ater, Arion rufus and Arion lusitanicus) are reported. Autumn collected slugs were cold acclimated in the laboratory and subjected to freezing conditions simulating likely winter temperatures in their habitat. Slugs spontaneously froze at about -4 °C when cooled under dry conditions, but freezing of body fluids was readily induced at -1 °C when in contact with external ice crystals. All three species survived freezing for 2 days at -1 °C, and some A. rufus and A. lusitanicus also survived freezing at -2 °C. (1)H NMR spectroscopy revealed that freezing of body fluids resulted in accumulation of lactate, succinate and glucose. Accumulation of lactate and succinate indicates that ATP production occurred via fermentative pathways, which is likely a result of oxygen depletion in frozen tissues. Glucose increased from about 6 to 22 µg/mg dry tissue upon freezing in A. rufus, but less so in A. ater and A. lusitanicus. Glucose may thus act as a cryoprotectant in these slugs, although the concentrations are not as high as reported for other freeze tolerant invertebrates.

Revision of the Afrotropical species of the hover fly genus Mesembrius Rondani (Diptera, Syrphidae) using morphological and molecular data.

The Afrotropical representatives of the hover fly genus Mesembrius Rondani, 1857 (Diptera) are divided into two subgenera, namely Mesembrius s.s. and Vadonimyia Séguy, 1951 and, in this present work, the subgenus Mesembrius s.s. is revised. A total of 23 Mesembrius s.s. species are recognised for the Afrotropics. Known species are re-described and six species new to science are described: Mesembrius arcuatus sp. nov., M. copelandi sp. nov., M. longipilosus sp. nov., M. sulcus sp. nov., M. tibialis sp. nov. and M. vockerothi sp. nov. Mesembrius africanus (Verrall, 1898) is considered a junior synonym of M. senegalensis (Macquart, 1842), M. ctenifer Hull, 1941 a junior synonym of M. caffer (Loew, 1858), M. lagopus (Loew, 1869) a junior synonym of M. capensis (Macquart, 1842) and M. platytarsis Curran, 1929 a junior synonym of M. simplicipes Curran, 1929. The females of Mesembrius chapini Curran, 1939, M. rex Curran, 1927 and M. regulus (Hull, 1937) are described for the first time. Lectotypes are designated for Mesembrius caffer, M. capensis, M. cyanipennis (Bezzi, 1915), M. minor (Bezzi, 1915), M. senegalensis, M. strigilatus (Bezzi, 1912) and M. tarsatus (Bigot, 1883). Separate identification keys for males and females are presented. We obtained 236 DNA barcodes for 18 species. The relationships amongst the different Mesembrius species are briefly discussed, based on morphological and DNA barcode data.

Taxonomic revision of the Afrotropical hover fly genus Senaspis Macquart (Diptera, Syrphidae).

The representatives of the Afrotropical hover fly genus Senaspis Macquart (Diptera) are revised. In total, ten species are recognized. Senaspis apophysata (Bezzi) is herewith placed as junior synonym of S. flaviceps Macquart, S. livida (Bezzi) is herewith placed as junior synonym of S. dentipes (Macquart) and S. griseifacies (Bezzi) is herewith placed as junior synonym of S. haemorrhoa (Gerstaecker). All species are redescribed and an identification key is provided. DNA barcoding analysis (7 species, 64 barcodes) showed that the technique can be used to unambiguously identify the species. The relationships among the different Senaspis species are discussed based on morphological and DNA data.

Taxonomic revision of the Afrotropical Phytomia Guérin-Méneville (Diptera: Syrphidae).

The Afrotropical representatives of the hoverfly genus Phytomia Guérin-Méneville (Diptera) are revised. In total, 19 species are recognized of which three are new to science: Phytomia austeni sp. nov., P. memnon sp. nov., and P. pallida sp. nov. Phytomia neavei Bezzi is considered a junior synonym of P. kroeberi (Bezzi), P. noctilio Speiser a junior synonym of P. pubipennis Bezzi, and P. ephippium Bezzi a junior synonym of P. melas (Bezzi). Lectotypes are designated for the following species: Megaspis bulligera Austen, Megaspis erratica Bezzi, and Megaspis poensis Bezzi. In addition, unpublished lectotype designations are hereby formally published for the following species: Megaspis bullata Loew, Megaspis curta Loew, and Megaspis capito Loew. Phytomia curta (Loew) is considered a valid species, and differentiated from P. natalensis (Macquart). Phytomia fronto Loew is tentatively considered to belong to the genus Simoides Loew. The relationship between the different Phytomia species, as well as the relationship between Phytomia and Simoides, is briefly discussed based on morphological and DNA data.

Mycobacterium ulcerans Population Genomics To Inform on the Spread of Buruli Ulcer across Central Africa.

Buruli ulcer is a neglected tropical disease of skin and subcutaneous tissue caused by infection with the pathogen Mycobacterium ulcerans Many critical issues for disease control, such as understanding the mode of transmission and identifying source reservoirs of M. ulcerans, are still largely unknown. Here, we used genomics to reconstruct in detail the evolutionary trajectory and dynamics of M. ulcerans populations at a central African scale and at smaller geographical village scales. Whole-genome sequencing (WGS) data were analyzed from 179 M. ulcerans strains isolated from all Buruli ulcer foci in the Democratic Republic of the Congo, The Republic of Congo, and Angola that have ever yielded positive M. ulcerans cultures. We used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our phylogeographic analysis revealed one almost exclusively predominant sublineage of M. ulcerans that arose in Central Africa and proliferated in its different regions of endemicity during the Age of Discovery. We observed how the best sampled endemic hot spot, the Songololo territory, became an area of endemicity while the region was being colonized by Belgium (1880s). We furthermore identified temporal parallels between the observed past population fluxes of M. ulcerans from the Songololo territory and the timing of health policy changes toward control of the Buruli ulcer epidemic in that region. These findings suggest that an intervention based on detecting and treating human cases in an area of endemicity might be sufficient to break disease transmission chains, irrespective of other reservoirs of the bacterium.IMPORTANCE Buruli ulcer is a destructive skin and soft tissue infection caused by Mycobacterium ulcerans The disease is characterized by progressive skin ulceration, which can lead to permanent disfigurement and long-term disability. Currently, the major hurdles facing disease control are incomplete understandings of both the mode of transmission and environmental reservoirs of M. ulcerans As decades of spasmodic environmental sampling surveys have not brought us much closer to overcoming these hurdles, the Buruli ulcer research community has recently switched to using comparative genomics. The significance of our research is in how we used both temporal associations and the study of the mycobacterial demographic history to estimate the contribution of humans as a reservoir in Buruli ulcer transmission. Our approach shows that it might be possible to use bacterial population genomics to assess the impact of health interventions, providing valuable feedback for managers of disease control programs in areas where health surveillance infrastructure is poor.

DNA barcoding fishes from the Congo and the Lower Guinean provinces: Assembling a reference library for poorly inventoried fauna.

The Congolese and Lower Guinean ichthyological provinces are understudied hotspots of the global fish diversity. Here, we barcoded 741 specimens from the Lower and Middle Congo River and from three major drainage basins of the Lower Guinean ichthyological province, Kouilou-Niari, Nyanga and Ogowe. We identified 194 morphospecies belonging to 82 genera and 25 families. Most morphospecies (92.8%) corresponded to distinct clusters of DNA barcodes. Of the four morphospecies present in both neighbouring ichthyological provinces, only one showed DNA barcode divergence <2.5%. A small fraction of the fishes barcoded here (12.9% of the morphospecies and 16.1% of the barcode clusters representing putative species) were also barcoded in a previous large-scale DNA analysis of freshwater fishes of the Lower Congo published in 2011 (191 specimens, 102 morphospecies). We compared species assignments before and after taxonomic updates and across studies performed by independent research teams and observed that most cases of inconsistent species assignments were due to unknown diversity (undescribed species and unknown intraspecific variation). Our results report more than 17 putative new species and show that DNA barcode data provide a measure of genetic variability that facilitates the inventory of underexplored ichthyofaunae. However, taxonomic scrutiny, associated with revisions and new species descriptions, is indispensable to delimit species and build a coherent reference library.

Multiple Introductions and Recent Spread of the Emerging Human Pathogen Mycobacterium ulcerans across Africa.

Buruli ulcer (BU) is an insidious neglected tropical disease. Cases are reported around the world but the rural regions of West and Central Africa are most affected. How BU is transmitted and spreads has remained a mystery, even though the causative agent, Mycobacterium ulcerans, has been known for more than 70 years. Here, using the tools of population genomics, we reconstruct the evolutionary history of M. ulcerans by comparing 165 isolates spanning 48 years and representing 11 endemic countries across Africa. The genetic diversity of African M. ulcerans was found to be restricted due to the bacterium's slow substitution rate coupled with its relatively recent origin. We identified two specific M. ulcerans lineages within the African continent, and inferred that M. ulcerans lineage Mu_A1 existed in Africa for several hundreds of years, unlike lineage Mu_A2, which was introduced much more recently, approximately during the 19th century. Additionally, we observed that specific M. ulcerans epidemic Mu_A1 clones were introduced during the same time period in the three hydrological basins that were well covered in our panel. The estimated time span of the introduction events coincides with the Neo-imperialism period, during which time the European colonial powers divided the African continent among themselves. Using this temporal association, and in the absence of a known BU reservoir or-vector on the continent, we postulate that the so-called "Scramble for Africa" played a significant role in the spread of the disease across the continent.

Slug species- and population-specific effects on the end points of the Slug Mucosal Irritation test.

The Slug Mucosal Irritation test seems to be a promising method for the evaluation of the local tolerance of products applied to the mucosa. Furthermore, the Slug Mucosal Irritation test is a reliable method to classify chemicals accurately into three eye irritation categories based on the mucus production and the score for tissue damage. Until now the slug Arion lusitanicus collected in Belgium was always used as test organism. The present study investigated the effects of the slug population and species on the end points of the test and on the eye irritation classification. For this purpose, the eye irritation/damage test procedure and eye reference chemicals were used. Comparison of the results of one Belgian and two Swiss A. lusitanicus populations indicated that the geographic and ecological origins of slug populations did neither influence the mucus production, nor the score for tissue damage. Slug species-specific effects on the test end points were investigated by comparing the data of Belgian Limax flavus with corresponding data of Belgian A. lusitanicus. L. flavus produced more mucus than A. lusitanicus, so that the mucus production cut-off values had to be increased. Therefore, the results indicated that the test procedure and prediction model have to be optimised and validated, if other slug species are used instead of A. lusitanicus.

Spatial spreading of Echinococcus multilocularis in Red foxes (Vulpes vulpes) across nation borders in Western Europe.

The occurrence of the fox tapeworm Echinococcus multilocularis in Red foxes was studied in Belgium and a neighbouring region in The Netherlands. A total number of 1202 foxes were analysed (1018 in Belgium and 184 in The Netherlands) of which 179 were infected with E. multilocularis (164 in Belgium and 15 in The Netherlands). Further, the spatial distribution of infection among sampled foxes was analysed with an ellipsoidal gradient, demonstrating a decreasing prevalence in northwestern direction. Using this gradient, we showed that the spatial patterns of infection in Belgium and the neighbouring region in The Netherlands correspond, indicating a continuous distribution of E. multilocularis across the nation borders. Part of the Belgian data allowed investigating temporal changes in the spatial distribution of E. multilocularis. This revealed a northwestern spread of E. multilocularis.