Spatio-temporal population genetic structure of the parasitic mite Spinturnix bechsteini is shaped by its own demography and the social system of its bat host

Information about the population genetic structures of parasites is important for an understanding of parasite transmission pathways and ultimately the co-evolution with their hosts. If parasites cannot disperse independently of their hosts, a parasite's population structure will depend upon the host's spatial distribution. Geographical barriers affecting host dispersal can therefore lead to structured parasite populations. However, how the host's social system affects the genetic structure of parasite populations is largely unknown. We used mitochondrial DNA (mtDNA) to describe the spatio-temporal population structure of a contact-transmitted parasitic wing mite ( Spinturnix bechsteini ) and compared it to that of its social host, the Bechstein's bat ( Myotis bechsteinii ). We observed no genetic differentiation between mites living on different bats within a colony. This suggests that mites can move freely among bats of the same colony. As expected in case of restricted inter-colony dispersal, we observed a strong genetic differentiation of mites among demographically isolated bat colonies. In contrast, we found a strong genetic turnover between years when we investigated the temporal variation of mite haplotypes within colonies. This can be explained with mite dispersal occuring between colonies and bottlenecks of mite populations within colonies. The observed absence of isolation by distance could be the result from genetic drift and/or from mites dispersing even between remote bat colonies, whose members may meet at mating sites in autumn or in hibernacula in winter. Our data show that the population structure of this parasitic wing mite is influenced by its own demography and the peculiar social system of its bat host.     

Isolation and cross‐familial amplification of 41 microsatellites for the brook charr (Salvelinus fontinalis)

The brook charr (Salvelinus fontinalis; Osteichthyes: Salmonidae) is a phenotypically diverse fish species inhabiting much of North America. But relatively few genetic diagnostic resources are available for this fish species. We isolated 41 microsatellites from S. fontinalis polymorphic in one or more species of salmonid fish. Thirty‐seven were polymorphic in brook charr, 15 in the congener Arctic charr (Salvelinus alpinus) and 14 in the lake charr (Salvelinus namaycush). Polymorphism was also relatively high in Oncorhynchus, where 21 loci were polymorphic in rainbow trout (Oncorhynchus mykiss) and 16 in cutthroat trout (Oncorhynchus clarkii) but only seven and four microsatellite loci were polymorphic in the more distantly related lake whitefish (Coregonus clupeaformis) and Atlantic salmon (Salmo salar), respectively. One duplicated locus (Sfo228Lav) was polymorphic at both duplicates in S. fontinalis.     

Late Miocene Carnivora from Chad: Lutrinae (Mustelidae)

We describe extensive Late Miocene fossil Lutrinae from Toros-Menalla, Chad. A minimum of four species are present in this fossiliferous area. Such a large number of species, diverse in size and dental morphology, is significant and unique in the fossil record of the subfamily Lutrinae in the Neogene of Africa. Two new taxa are described, Sivaonyx beyi sp. nov. and Djourabus dabba gen. nov. sp. nov. ; the two other species, which are represented by more fragmentary remains, are assigned to Lutrinae indet. aff. Torolutra sp. and Lutrinae indet. aff. Aonyx sp. Sivaonyx beyi is the best known of the species. It is represented by many dental remains and a subcomplete skeleton. Postcranial characters of this species are not particularly specialized. It is interpreted here as a terrestrial predator with poorly developed aquatic adaptations. Fossils of otters are known from ten different localities at Toros-Menalla, each of which yielded a single individual of one or two species. The presence of four morphologically distinct otters in the area is indicative of a palaeoenvironment with a relatively well-developed freshwater system of lakes and/or rivers.  © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society , 2008, 152 , 793–846.     

Megagametophyte development of Nymphaea nouchali Burm. f. (Nymphaeaceae)

The development of reproductive cells has been analysed in Nymphaea nouchali , family Nymphaeaceae, subclass Magnoliidae. Our observations on embryo sac development differ from those in the literature. Megasporogenesis results in a triad of one micropylar cell and two innermost megaspores. Embryo sacs derive from a single functional megaspore and are tetranucleate. Megasporogenesis is monosporic and of the Polygonum type, but mega-gametogenesis is of Oenothera type.     

Using species distribution models to locate animal aggregations: a case study with Hippodamia undecimnotata (Schneider) overwintering aggregation sites

1. The protection of animals' aggregation sites is increasingly seen as a key conservation strategy. However, to efficiently protect aggregation sites, they need to be accurately located. Species distribution models (SDMs) are an important tool in biological conservation to predict spatial distribution of species and they are used here to predict the distribution of the aggregation sites of a ladybird (Coleoptera: Coccinellidae) species. 2. Hippodamia undecimnotata forms spectacular overwintering aggregations at the same locations every year across southern and eastern Europe. In this study, an SDM was developed and its performance tested for H. undecimnotata aggregations in southwest France. Moreover, the study looked at how environmental variables correlate with ladybirds' abundance in the aggregation sites. 3. The occurrence of aggregations was best described by one model including isolated prominent object, pesticide risk, altitude and vegetation coverage. Furthermore, ladybird abundance at the aggregation sites is positively correlated with altitude. The SDM occurrence model performance was found to be high (area under the curve = 0.92 and true skill statistic = 0.78). 4. It is suggested that H. undecimnotata may be an umbrella species, because some aggregation sites were also used by other ladybird species. Therefore, the protection of the aggregation sites of this species may benefit several other species. 5. This study provides nature conservation stakeholders with a tool to locate overwintering aggregations, a first step towards the protection of these sites.     

DNA barcoding and morphology reveal three cryptic species of Anania (Lepidoptera: Crambidae: Pyraustinae) in North America,all distinct from their European counterpart

Anania coronata (Hufnagel), a Holarctic species of pyraustine crambid moth, has long been treated as having two geographically separated subspecies – the nominotypical Anania coronata in the Palaearctic Region and Anania coronata tertialis (Guenée) in the Nearctic Region. Maximum likelihood and Bayesian inference analysis of mitochondrial DNA barcodes both recover four well‐supported, reciprocally monophyletic groups within Anania coronata. Qualitative and quantitative analyses of genital structures reveal diagnostic differences that correspond to the four barcode lineages. On the basis of both molecular and morphological evidence, we conclude that Anania coronata is actually a complex of four species. Anania coronata (Hufnagel) is restricted to Europe, whereas three species occur in North America: Anania tertialis (Guenée), Anania plectilis (Grote & Robinson) and Anania tennesseensis sp.n. Yang.     

Cytogeography of Gentianaceae–Exaceae in Africa,with a special focus on Sebaea: the possible role of dysploidy and polyploidy in the evolution of the tribe

Unlike other tribes of Gentianaceae, Exaceae have so far received little attention regarding their karyological evolution. Indeed, only 35 chromosome number counts (19 species) have been referenced to date, representing only a negligible fraction of the tribal diversity. In this paper, we performed an intensive chromosome count on material collected in the field (South and central Africa, plus Madagascar), encompassing 155 populations and c. 60 species from four genera of Exaceae, including Exacum, Ornichia, Sebaea and Tachiadenus. Fifty nine species (14 Exacum, one Ornichia, 42 Sebaea and two Tachiadenus) were examined for the first time, revealing a broad set of chromosome numbers (2n = 18, 28, 32, 36, 42, 56) and the occurrence of polyploid systems within Exacum and Sebaea. These results allow us to postulate x = 7, 8 or 9 as possible base chromosome numbers for Exaceae and emphasize the importance of both dysploidy and polyploidy processes in the evolution of the tribe. Finally, chromosome numbers appear to be associated to some morphological or geographical traits, suggesting new systematic combinations and likely active speciation patterns in the group. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 556–566.     

The ghost of hybrids past: fixation of arctic charr (Salvelinus alpinus) mitochondrial DNA in an introgressed population of lake trout (S. namaycush)

Complete fixation of arctic charr ( Salvelinus alpinus ) mitochondrial DNA (mtDNA) was observed in a southern Québec population of lake trout ( S. namaycush ). This introgressed population otherwise appeared to be normal with regard to lake trout morphology and three species-diagnostic microsatellite loci. Arctic charr do not occur in the area, suggesting that the hybridization event was prehistoric. Of several possible hypotheses, the most plausible explanation for this aberrant population is that hybridization occurred in situ soon after deglaciation, with repeated backcrossing of hybrids with lake trout. Fixation of S. alpinus mtDNA in the population may have occurred either by chance (drift) or selection, although indirect evidence and data from similarly introgressed brook trout ( S. fontinalis ) populations in the region suggest that selection favouring the S. alpinus mitochondrial type and/or associated nuclear genes may have been involved.