Holarctic phylogeography of the tundra shrew (Sorex tundrensis) based on mitochondrial genes

A range‐wide phylogeographic study of the tundra shrew (Sorex tundrensis) was performed using cytochrome b and cytochrome oxidase I (COI) mitochondrial genes. The results based on 121 specimens from 42 localities demonstrate that the tundra shrew is divided into five main mitochondrial DNA phylogenetic lineages with largely parapatric distribution. In addition to a single Nearctic clade (Alaska) four Palearctic clades are identified: Western (Northen Urals, Kazakhstan, South‐West Siberia), Eastern (from East Transbaikalia and the Middle Amur to Chukotka), South Central (Central Siberia, the Altai, the Dzhungarian Alatau) and North Central (Northern Siberia, Central Yakutia). Date estimates obtained by use of a molecular clock corrected for potential rate decay suggest Late Pleistocene age for the most recent common ancestor of all contemporary tundra shrew populations. Relatively high genetic divergence between phylogroups (0.95–1.6%) indicates that the observed phylogeographic structure was initiated by historical events that predated the Last Glacial Maximum. We assume that, being more cold‐ and arid‐tolerant, tundra shrew underwent expansion during an early cold phase of the Last Glacial and spread through its recent range earlier than most of other Siberian red‐toothed shrews. Comparative phylogeographic analysis of Siberian shrews and rodents suggests that evolutionary histories of species associated with azonal or open habitats show important differences compared to forest species. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 721–746.     

Persistent Controversy in Statistical Approaches in Wildlife Sciences: A Perspective of Students

ABSTRACT The controversy over the use of null hypothesis statistical testing (NHST) has persisted for decades, yet NHST remains the most widely used statistical approach in wildlife sciences and ecology. A disconnect exists between those opposing NHST and many wildlife scientists and ecologists who conduct and publish research. This disconnect causes confusion and frustration on the part of students. We, as students, offer our perspective on how this issue may be addressed. Our objective is to encourage academic institutions and advisors of undergraduate and graduate students to introduce students to various statistical approaches so we can make well-informed decisions on the appropriate use of statistical tools in wildlife and ecological research projects. We propose an academic course that introduces students to various statistical approaches (e.g., Bayesian, frequentist, Fisherian, information theory) to build a foundation for critical thinking in applying statistics. We encourage academic advisors to become familiar with the statistical approaches available to wildlife scientists and ecologists and thus decrease bias towards one approach. Null hypothesis statistical testing is likely to persist as the most common statistical analysis tool in wildlife science until academic institutions and student advisors change their approach and emphasize a wider range of statistical methods.     

THE WHISTLED SONGS OF THE EUROPEAN STARLING STURNUS VULGARIS AND THE SPOTLESS STARLING STURNUS UNICOLOR IN NORTH-EAST SPAIN

ABSTRACT

This paper describes the whistled songs of two allopatric populations of the European starling and spotless starling in NE Spain. The results show that European starlings in NE Spain sing the same whistled themes found earlier in other European populations and confirm the universal character of these themes. There are some differences between European starlings from NE Spain and other populations: rising phases appear for Inflection theme high-form, Inflection theme and Simple theme, and also differences of rate of emission appear for others (Rhythmic theme). Harmonic theme has not been found. Likewise, the first analysis of the spotless starling's whistled song shows that it shares the same general whistled song structure with the European starling; whistles have similar structural parameters (modulation, duration, frequency) and can be classified in the same categories or themes; a new theme appears, the Trilled theme, which has not been found to date in the European starling. Dialectal areas have been found in both species for the same themes (Inflection theme, Simple theme). The males of both studied populations have larger repertoires in comparison to other studied populations of the European starling.     

Reproductive biology of the fire-bellied toads, Bombina bombina and B. variegata (Anura: Discoglossidae): egg size, clutch size and larval period length differences

Clutch size, egg size, larval size and duration of larval period were estimated for samples of Bombina bombina and B. variegata from several populations. Bombina variegata lays fewer eggs per batch (mean 17.4) than B. bombina (mean 32.5). The volume of B. variegata eggs is 2.4 times greater and the dry weight 2.3 times greater than that of B. bombina. As a consequence, the volume of B. variegata hatchlings and their dry weight are respectively 1.9 times and 2.5 times greater than that of B. bombina. Analysis of variance showed that variation of egg size in B. variegata is significantly greater than in B. bombina. When reared under laboratory conditions freshly metamorphosed individuals of both species showed no difference in body size or weight. Although growth rates are equal, tadpoles of B. variegata reached metamorphosis 14 days earlier than B. bombina tadpoles because of differences in size of hatchlings. Differences in reproductive parameters found for the two European Bombina species can be interpreted as adaptations to contrasting environments in which they breed.     

In Vivo and In Vitro Activity by Diverse Chelators against Trypanosoma brucei brucei1

A system of prescreens and screen has been developed to select chelators as potential drugs against Trypanosoma brucei brucei EATRO 110. The chelators tested were nearly all commercially available, low molecular, and having moderate to high affinity for Fe(III). We prescreened 70 compounds showing heme-sparing or inhibitory activity in a Crithidia fasciculata growth system having excess Fe and minimal hemin. Of these, 45 were highly trypanocidal for suspensions of bloodstream T. b. brucei; criteria of activity here were immobilization, lysis, and loss of infectivity. Eighteen of the chelators highly active in the suspension prescreen were tried in T. b. brucei-infected mice. Thirteen of these chelators were curative in mice with 24-h infections, that is, they allowed survival >30 days beyond the untreated controls. 3,4-Dihydroxycinnamic acid (caffeic acid). 2,9-dimethyl-1, 10 phenanthroline (neocuproine), and 2-pyridinecarboxaldehyde-2-pyridyl-hydrazone cured five out of five mice after an i.v. dose of 100 mg/kg. Salicylaldehyde thiosemicarbazone cured five out of five mice at an i.p. dose of 500 mg/kg. Lesser activity was shown by several other chelators.     

Variation in ephippial buoyancy in Daphnia pulicaria

1. Freshwater zooplankton often produce diapausing eggs to survive environmental stress. The diapausing eggs of Daphnia (Crustacea, Cladocera) are encased in an ephippium that either floats at the surface or sinks to the sediment. These two types of ephippia may represent different strategies between spatial (floaters) and temporal (sinkers) dispersal of offspring. 2. We observed floating and sinking characteristics of ephippia obtained from eight lakes. We then conducted an experiment with 26 Daphnia pulicaria clones obtained from six of these lakes and observed the production of buoyant and non‐buoyant ephippia under high and low food conditions. 3. Ephippia were more often non‐buoyant than buoyant both from females caught in nature and those reared in the laboratory. The experiment revealed that each clone was able to produce both types of ephippia, but that there was considerable among‐clone variation in the percentage of non‐buoyant ephippia produced. 4. We conclude that production of non‐buoyant versus buoyant ephippia may be driven by both genetic and environmental factors.     

Numerical taxonomy of Juniperus thurifera, J. excelsa and J. foetidissima (Cupressaceae) based on morphological characters

Juniperus excelsa and J. thurifera are considered to originate from the same ancestor. As a result of occurring in geographically isolated refuges – J. excelsa in SE Europe and SW Asia and J. thurifera in SW Europe and NW Africa – their divergence could have taken place at the end of the Tertiary, with the climate cooling. Juniperus foetidissima occurs in SE Europe and SW Asia in territories shared with J. excelsa and is similar to and sometimes misidentified with it. The occurrence of the latter two species over the same area suggests they should be more similar to each other than to the geographically distant J. thurifera . Four populations of J. excelsa ssp. excelsa , four of J. thurifera and two of Juniperus foetidissima were examined on the basis of features of 10 cones and 10 shoots of 18–36 specimens each. Results of discrimination analysis, Mahalanobis distances and cluster analysis showed great similarity to J. excelsa and J. thurifera , while J. foetidissima was more distant. The results support the hypothesis of a common ancestor of J. excelsa and J. thurifera , but suggest another origin of J. foetidissima .  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 155 , 483–495.     

Melanins in Physiological Conditions Protect Against Lipoperoxidation. A Study on Albino and Pigmented Xenopus

The susceptibility to lipoperoxidation in liver of albino and pigmented Xenopus laevis Daudin, has been studied. Albino Xenopus liver was richer in polyunsaturated fatty acids (PUFAs) than the pigmented one; moreover, it was also richer in mitochondrial superoxide dismutase (MnSOD) and in reduced glutathione (GSH). The thiobarbituric acid-reactive substances (TBARS) values were more abundant in the albino tissue compared to the pigmented tissue both during spontaneous and Fe⁺⁺ induced lipoperoxidation. Therefore, when isolated and purified melanin, in physiological quantities, was added to albino tissue, the TBARS values drastically decreased. Thus, melanin, in our experimental conditions, protects the albino tissue even more than SOD and GSH do. Melanin, in our opinion, acts as an antioxidant, because it is able to scavenge O₂^?.