The role of competition and habitat in structuring small mammal communities in a tropical montane ecosystem in southern India

Small mammals were sampled in two natural habitats (montane stunted evergreen forests and montane grassland) and four anthropogenic habitats (tea, wattle, bluegum and pine plantation) in the Upper Nilgiris in southern India. Of the species trapped, eight were in montane evergreen forests and three were in other habitats. Habitat discrimination was studied in the rodents Rattus rattus and Mus famulus and the shrew Suncus montanus in the montane forest habitat. Multivariate tests on five variables (canopy cover, midstorey density, ground cover, tree density, canopy height) showed that R. rattus uses areas of higher tree density and lower canopy cover. Suncus montanus and M. famulus use habitat with higher tree density and ground cover and lower canopy height. Multivariate tests did not discriminate habitat use between the species. Univariate tests, however, showed that M. famulus uses areas of higher tree density than R. rattus and S. montanus. Rattus rattus was the dominant species in the montane forest, comprising 60.9% of total density, while the rodent Millardia meltada was the dominant species in the grassland. Studies of spatial interaction between these two species in habitats where they coexisted showed neither overlap nor avoidance between the species. Rattus rattus, however, did use areas of lower ground cover than did M. meltada. The analysis of spatial interactions between the species, habitat discrimination and use, and the removal experiments suggest that interspecific competition may not be a strong force in structuring these small mammal communities. There are distinct patterns in the use of different habitats by some species, but microhabitat selection and segregation is weak. Other factors such as intraspecific competition may play a more important role in these communities.

Taming Control Divergence in GPUs through Control Flow Linearization

Branch divergence is a very commonly occurring performance problem in GPGPU in which the execution of diverging branches is serialized to execute only one control flow path at a time. Existing hardware mechanism to reconverge threads using a stack causes duplicate execution of code for unstructured control flow graphs. Also the stack mechanism cannot effectively utilize the available parallelism among diverging branches. Further, the amount of nested divergence allowed is also limited by depth of the branch divergence stack. In this paper we propose a simple and elegant transformation to handle all of the above mentioned problems. The transformation converts an unstructured CFG to a structured CFG without duplicating user code. It incurs only a linear increase in the number of basic blocks and also the number of instructions. Our solution linearizes the CFG using a predicate variable. This mechanism reconverges the divergent threads as early as possible. It also reduces the depth of the reconvergence stack. The available parallelism in nested branches can be effectively extracted by scheduling the basic blocks to reduce the effect of stalls due to memory accesses. It can also increase execution efficiency of nested loops with different trip counts for different threads. We implemented the proposed transformation at PTX level using the Ocelot compiler infrastructure. We evaluated the technique using various benchmarks to show that it can be effective in handling the performance problem due to divergence in unstructured CFGs.

Cross-species chromosome painting in the golden mole and elephant-shrew: support for the mammalian clades Afrotheria and Afroinsectiphillia but not Afroinsectivora

Cross-species painting (fluorescence in situ hybridization) with 23 human (Homo sapiens (HSA)) chromosome-specific painting probes (HSA 1-22 and the X) was used to delimit regions of homology on the chromosomes of the golden mole (Ghrysochloris asiaticus) and elephant-shrew (Elephantulus rupestris). A cladistic interpretation of our data provides evidence of two unique associations, HSA 1/19p and 5/21/3, that support Afrotheria. The recognition of HSA 5/3/21 expands on the 3/21 synteny originally designated as an ancestral state for all eutherians. We have identified one adjacent segment combination (HSA2/8p/4) that is supportive of Afroinsectiphillia (aardvark, golden mole, elephant-shrew). Two segmental combinations (HSA 10q/17 and HSA 3/20) unite the aardvark and elephant-shrews as sister taxa. The finding that segmental syntenies in evolutionarily distant taxa can improve phylogenetic resolution suggests that they may be useful for testing sequence-based phylogenies of the early eutherian mammals. They may even suggest clades that sequence trees are not recovering with any consistency and thus encourage the search for additional rare genomic changes among afrotheres.

Evolution and biogeography of talpid moles from continental East Asia and the Japanese islands inferred from mitochondrial and nuclear gene sequences

We sequenced the cytochrome b gene from two little-studied mammal species from the highlands of Southwest China, the long-tailed mole Scaptonyx fusicaudus and the gracile shrew-like mole Uropsilus gracilis. This data was used to examine the phylogenetic r

A multi-locus phylogeny of Nectogalini shrews and influences of the paleoclimate on speciation and evolution

Nectogaline shrews are a major component of the small mammalian fauna of Europe and Asia, and are notable for their diverse ecology, including utilization of aquatic habitats. So far, molecular phylogenetic analyses including nectogaline species have been unable to infer a well-resolved, well-supported phylogeny, thus limiting the power of comparative evolutionary and ecological analyses of the group. Here, we employ Bayesian phylogenetic analyses of eight mitochondrial and three nuclear genes to infer the phylogenetic relationships of nectogaline shrews. We subsequently use this phylogeny to assess the genetic diversity within the genus Episoriculus, and determine whether adaptation to aquatic habitats evolved independently multiple times. Moreover, we both analyze the fossil record and employ Bayesian relaxed clock divergence dating analyses of DNA to assess the impact of historical global climate change on the biogeography of Nectogalini. We infer strong support for the polyphyly of the genus Episoriculus. We also find strong evidence that the ability to heavily utilize aquatic habitats evolved independently in both Neomys and Chimarrogale + Nectogale lineages. Our Bayesian molecular divergence analysis suggests that the early history of Nectogalini is characterized by a rapid radiation at the Miocene/Pliocene boundary, thus potentially explaining the lack of resolution at the base of the tree. Finally, we find evidence that nectogalines once inhabited northern latitudes, but the global cooling and desiccating events at the Miocene/Pliocene and Pliocene/Pleistocene boundaries and Pleistocene glaciation resulted in the migration of most Nectogalini lineages to their present day southern distribution. (C) 2010 Elsevier Inc. All rights reserved.

Sorex bedfordiae has the Smallest Diploid Chromosome Number of the XY Group in the Genus Sorex (Mammalia, Soricidae)

Karyological data on the lesser stripe-backed shrew, Sorex bedfordiae, were obtained from four specimens collected on Mt. Laojun, Lijiang District, Yunnan Province, China. Three of the four S. bedfordiae specimens had karyotypes consisting of 2n=26, NFa=4

Ovulation in the tree shrew (Tupaia belangeri) induced by gonadotrophins

The induction of ovulation by exogenous gonadotrophins is an important approach for recovering oocytes used for studies on the reproductive biology of some mammals. In the present study, pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadot

Molecular cloning and expression characterization of ApoC-I in the orange-spotted grouper

Endogenous yolk nutrients are crucial for embryo and larval development in fish, but developmental behavior of the genes that control yolk utilization remains unknown. Apolipoproteins have been shown to play important roles in lipid transport and uptake through the circulation system. In this study, EcApoC-I, the first cloned ApoC-I in teleosts, has been screened from pituitary cDNA library of female orange-spotted grouper (Epinephelus coioides), and the deduced amino acid sequence shows 43.5% identity to one zebrafish (Danio rerio) hypothetical protein similar to ApoC-I, and 21.2%, 21.7%, 22.5%, 20%, and 22.5% identities to Apo C-I of human (Homo sapiens), house mouse (Mus musculus), common tree shrew (Tupaia glis), dog (Canis lupus familiaris) and hamadryas baboon (Papio hamadryas), respectively. Although the sequence identity is low, amphipathic alpha-helices with the potential to bind to lipid were predicted to exist in the EcApoC-I. RT-PCR analysis revealed that it was first transcribed in gastrula embryos and maintained a relatively stable expression level during the following embryogenesis. During embryonic and early larval development, a very high level of EcApoC-I expression was in the yolk syncytial layer, indicating that it plays a significant role in yolk degradation and transfers nutrition to the embryo and early larva. By the day 7 after hatching, EcApoC-I transcripts were observed in brain. In adult, EcApoC-I mRNA was detected abundantly in brain and gonad. In transitional gonads, the EcApoC-I expression is restricted to the germ cells. The data suggested that EcApoC-I might play an important role in brain and gonad morphogenesis and growth.

‘Invasional meltdown’: evidence for unexpected consequences and cumulative impacts of multispecies invasions

Empirical support for ‘invasional meltdown’, where the presence of one invading species facilitates another and compounds negative impacts on indigenous species, is equivocal with few convincing studies. In Ireland, the bank vole was introduced 80 years ago and now occupies a third of the island. The greater white-toothed shrew arrived more recently within the invasive range of the bank vole. We surveyed the abundance of both invasive species and two indigenous species, the wood mouse and pygmy shrew, throughout their respective ranges. The negative effects of invasive on indigenous species were strong and cumulative bringing about species replacement. The greater white-toothed shrew, the second invader, had a positive and synergistic effect on the abundance of the bank vole, the first invader, but a negative and compounding effect on the abundance of the wood mouse and occurrence of the pygmy shrew. The gradual replacement of the wood mouse by the bank vole decreased with distance from the point of the bank vole’s introduction whilst no pygmy shrews were captured where both invasive species were present. Such interactions may not be unique to invasions but characteristic of all multispecies communities. Small mammals are central in terrestrial food webs and compositional changes to this community in Ireland are likely to reverberate throughout the ecosystem. Vegetation composition and structure, invertebrate communities and the productivity of avian and mammalian predators are likely to be affected. Control of these invasive species may only be effected through landscape and habitat management.

Chromosome synapsis and recombination in simple and complex chromosomal heterozygotes of tuco-tuco (Ctenomys talarum: Rodentia: Ctenomyidae):Rodentia: Ctenomyidae)

The chromosomal speciation hypothesis suggests that irregularities in synapsis, recombination, and segregation in heterozygotes for chromosome rearrangements may restrict gene flow between karyotypically distinct populations and promote speciation. Ctenomys talarum is a South American subterranean rodent inhabiting the coastal regions of Argentina, whose populations polymorphic for Robertsonian and tandem translocations seem to have a very restricted gene flow. To test if chromosomal differences are involved in isolation among its populations, we examined chromosome pairing, recombination, and meiotic silencing of unsynapsed chromatin in male meiosis of simple and complex translocation heterozygotes using immunolocalization of the MLH1 marking mature recombination nodules and phosphorylated histone γH2A.X marking unrepaired double-strand breaks. We observed small asynaptic areas labeled by γH2A.X in pericentromeric regions of the chromosomes involved in the trivalents and quadrivalents. We also observed a decrease of recombination frequency and a distalization of the crossover distribution in the heterozygotes and metacentric homozygotes compared to acrocentric homozygotes. We suggest that the asynapsis of the pericentromeric regions are unlikely to induce germ cell death and decrease fertility of the heterozygotes; however, suppressed recombination in pericentromeric areas of the multivalents may reduce gene flow between chromosomally different populations of the Talas tuco-tuco.

Taxonomical and biogeographical problems in Mediterranean shrews of the genus Crocidura (Mammalia, Insectivora) with reference to a new karyotype from Sicily (Italy)

Shrews of the genus Crocidura from Sicily revealed a new karyotype from Europe: 2n = 36, NF = 56, NFa = 52. With reference to the revision of Vesmanis (1976), this shrew is provisionally attributed to C. caudata Miller, 1901 and it is proposed to call it the "Sicilian shrew". Its chromosome complement is similar to that of shrews from Canary Islands and a species from Burundi (Central Africa), suggesting that it might have split off from a line of Paleotropical origin. Following these findings, the modern concept of Mediterranean island colonization by shrews must be revised. The distinctive characteristics of Mediterranean shrews should also be revised.

New Sorex araneus karyotypes from Germany and the postglacial recolonization of central Europe

New G-banded karyotypes from populations of the common shrew Sorex araneus Linnaeus, 1758 provide a clearer picture of the distribution of chromosome races in central Europe. As expected according to their occurrence in neighbouring countries, the Jutland (kq, no), Laska (k/o) and Drnholec (ko, nr) races are also found in Germany. A new chromosome race "Rugen" (kq) is described from this Baltic Island. Together with the previously recorded races Ulm and Mooswald (kr), six chromosome races are now known from Germany. The resulting distribution pattern is characterized by high frequencies of different race-specific metacentrics at the periphery of the country and clines with decreasing frequencies towards the centre which is occupied by the Ulm race. This race is acrocentric for all chromosome arms involved in the observed race-specific fusions and represents a buffer between the surrounding, more metacentric races. According to the present distribution of these metacentrics, a scenario for the postglacial recolonization of central Europe by S. araneus populations on three different routes is proposed: from the east along the northern slopes of the Carpathian Arc, from the south-east along the Danube Valley and from the south-west through the Upper Rhine Valley.

Are there two species of Pygmy Shrews (Sorex)? Revisiting the question using DNA sequence data

Pygmy Shrews in North America have variously been considered to be one species (Sorex hoyi) or two species (S. hoyi and S. thompsoni). Currently, only S. hoyi is recognized. In this study, we examine mitochondrial DNA sequence data for the cytochrome b gene to evaluate the level of differentiation and phylogeographic relationships among eleven samples of Pygmy Shrews from across Canada. Pygmy Shrews from eastern Canada (i.e., Ontario, Quebec, New Brunswick, Nova Scotia, and Prince Edward Island) are distinct from Pygmy Shrews from western Canada (Alberta, Yukon) and Alaska. The average level of sequence divergence between these clades (3.3%) falls within the range of values for other recognized pairs of sister species of shrews. A molecular clock based on third position transversion substitutions suggests that these two lineages diverged between 0.44 and 1.67 million years ago. These molecular phylogenetic data. combined with a reinterpretation of previously published morphological data, are suggestive of separate species status for S. hoyi and S. thompsoni as has been previously argued by others. Further analysis of specimens from geographically intermediate areas (e.g., Manitoba. northern Ontario) is required to determine if there is secondary contact and/or introgression between these two putative species.

Identification of three Sorex species with microsatellite markers

Three sibling species of shrews, the common shrew (Sorex araneus), the Valais shrew (S. antinorii) and the Jersey shrew (S. coronatus) are morphologically similar. Different techniques based on karyorypes, morphology, biochemistry and genetic markers have been developed to identify individuals from these taxa. In this paper, we have used multiple microsatellite markers (L13, L14 and L99) to identify 55 dead animals coming from the Tarentaise Valley in France. As some individuals showed an unclear pattern with loci previously thought to be diagnostic (Lugon-Moulin et al. 2000), we have used morphologic measurements (Hausser et al. 1991) to confirm the status of these animals. This analysis clearly showed the limitations of the use of genetic diagnostic markers that have been designed in local populations and then applied to a wider scale. Even if these markers have great advantages over other techniques (i.e. simple to use and do not require samples from living animals), they should always be used with caution. There is always a risk of a locus not being diagnostic in the sampling region or in finding individuals with hybrid genotypes. Additional genetic markers should then be used, simultaneously with other identification techniques, to be sure of the status of the individuals.

Human and Raptor Interactions in the Context of a Nomadic Society

This research project focuses on contemporary eagle-taming falconry practice of the Altaic Kazakhs animal herding society in Bayan Ulgii Province in Western Mongolia. It aims to contributing both theoretical and empirical criteria for cultural preservation of Asian falconry. This cultural as well as environmental discourse is illustrated with concentrated field research framed by ecological anthropology and ethno-ornithology from the viewpoint of “Human-Animal Interaction (HAI)” and “Human-Animal Behavior (HAB)”. Part I (Chapter 2 & 3) explores ethno-archaeological and ethno-ornithological dimensions by interpretive research of archaeological artefacts which trace the historical depth of Asian falconry culture. Part II (Chapter 4 & 5) provides an extensive ethnographic narrative of Altaic Kazakh falconry, which is the central part of this research project. The “Traditional Art and Knowledge (TAK)” in human-raptor interactions, comprising the entire cycle of capture, perch, feeding, training, hunting, and release, is presented with specific emphasis on its relation to environmental and societal context. Traditional falconry as integral part of a nomadic lifestyle has to face some critical problems nowadays which necessitate preventing the complete disappearance of this outstanding indigenous cultural heritage. Part III (Chapter 6 & 7) thus focuses on the cultural sustainability of Altaic Kazakh falconry. Changing livelihoods, sedentarisation, and decontextualisation are identified as major threats. The role of Golden Eagle Festivals is critically analysed with regard to positive and negative impact. This part also intends to contribute to the academic definition of eagle falconry as an intangible cultural heritage, and to provide scientific criteria for a preservation master plan, as well as stipulate local resilience by pointing to successive actions needed for conservation. This research project concludes that cultural sustainability of Altaic Kazakh falconry needs to be supported from the angles of three theoretical frameworks; (1) Cultural affairs for protection based on the concept of nature-guardianship in its cultural domain, (2) Sustainable development and improvement of animal herding productivity and herder’s livelihood, (3) Natural resource management, especially supporting the population of Golden Eagles, their potential prey animals, and their nesting environment.