Heterospecific hybrids often suffer from a lowered fitness relative to parental species. Contextdependent intrinsic costs of hybridization are partially due to a malfunction in cell biochemical machinery that affects metabolic rates at the organismal level. This study examines whether heterospecific hybridization influences the metabolic costs of maintenance in F1 hybrids between closely related newts, Triturus carnifex and T. dobrogicus. When controlled for body size, oxygen consumption in hybrid newts was 59–76 % higher than in the parental species. This suggests that high standard metabolic rates in hybrids may contribute to the costs of hybridization in newts.

Crested newts (Triturus cristatus superspecies) are a group of closely related species with parapatric distributions that are likely to interbreed where their ranges meet. Coexistence of three species of the complex (Triturus cristatus, T. dobrogicus and T. carnifex) has been recently confirmed in central Europe. In this study we aim to elucidate the distribution of crested newts in contact zones in the Czech Republic and Slovakia, and determine the extent of hybridization and introgression using nuclear (microsatellites and Randomly Amplified Polymorphic DNA, RAPD) and mitochondrial DNA (mtDNA) markers. Nuclear markers reveal hybrid zones between T. cristatus and T. dobrogicus at the foothills of the Carpathians in southern Slovakia, and between T. cristatus and T. carnifex in the southern parts of the Czech Republic. Analysis of mitochondrial cytochrome b sequences reveals T. cristatus and T. dobrogicus-specific haplotypes in contact zones in southern Slovakia. Surprisingly, most T. carnifex and individuals with mixed ancestry between T. carnifex and T. cristatus possess haplotypes specific for T. dobrogicus, most likely as a result of historical mtDNA introgression. Only one T. carnifex-specific haplotype carried by a single specimen is found in the Czech Republic. Our study shows that genetic structure of central European populations of crested newts is complex and influenced by historical and contemporary hybridization.

The goal of this paper was to test the hypothesis that weather conditions, such as temperature and rainfall, affect egg colouration in the great reed warbler Acrocephalus arundinaceus. We failed to find strong support for this hypothesis; nevertheless, our results indicate that temperature has an effect on some egg colour characteristics. Eggshell brightness (PC1) increased with increasing temperature at laying and eggs were darker in the colder year of the two-year study. On the other hand, UV-blue colouration (PC2) scores were higher in the warmer year. The amount of rainfall, however, had no effect on eggshell colouration. As there is an indication from other studies that weather may have an effect on egg appearance through the food availability, we encourage further testing the environmental hypothesis in other bird species. If this holds for more bird species, this would have important implications for the hypotheses about the adaptive function of bright eggshell colouration.

The attractiveness hypothesis predicts that females should bias the sex ratio of their offspring towards sons when mated to attractive males. Females of many socially monogamous bird species commonly engage in extra-pair fertilizations (EPFs). Assuming that extra-pair males are more attractive to females than their social partners, and that sons inherit superior traits from their fathers, extra-pair young should be more likely males. According to the maternal condition hypothesis male-biased sex ratio in offspring should be also associated with better female body condition. We evaluated these ideas in the scarlet rosefinch (Carpodacus erythrinus), socially monogamous songbird with moderate level of extra-pair fertilizations. Contrary to the attractiveness hypothesis we have found no significant effect of paternity (within-pair or extra-pair) on the sex of individual offspring. Furthermore, data did not suggest that females mated to males with more elaborated plumage colour were more likely to produce sons. However, consistently with the maternal condition hypothesis, high-quality females produced more sons than daughters. Our results indicate that scarlet rosefinch females may not be able to manipulate the primary sex ratio of their offspring in relation to the attractiveness of their mate, but they may adjust it according to their own condition.

Although the Prisoner's dilemma is a leading metaphor for the evolution of sociality, only a few studies demonstrate that this game indeed operates in nature. We offer an alternative perspective, in which parasites and their hosts are used as a model system, suggesting that Prisoner's dilemma may be rare due to different individuals experiencing variation in the payoffs they receive from alternative strategies. Ectoparasites (such as fleas) move stochastically between hosts, causing differential parasite burdens. The resulting variance in the need for cooperation — in this case cooperative allogrooming — means that payoffs for different strategies (e.g. cooperate and defect) are not fixed. Our simulations revealed that due to parasite dynamics, cooperation among hosts conforms to a mixture of two games: Mutualism and Cruel Bind, both of which are more likely to coerce individuals into mutual cooperation than Prisoner's dilemma. Though interesting, Prisoner's dilemma is in fact the least likely scenario. If payoff variation is common, the dominance of the Prisoner's dilemma paradigm may have made us unnecessarily puzzled by cooperation in nature.

Chamois (Rupicapra rupicapra) introductions were popular at the beginning of the 20th century when first animals were shipped from Austria to the Czech Republic and New Zealand. The historical record of the Czech introduction indicates Neuberg Mürzsteg Game Reserve in Eastern Alps, Styria, Austria as the main area of origin of founders. First animals for the New Zealand population are thought to have originated from Ebensee, Upper Austria, Austria and later more animals came from the Mürzsteg region. We sequenced mitochondrial control region of chamois from the introduced populations and their putative source areas, and we applied median-joining networks and Bayesian inference analysis to distinguish the regions of origin of female founders. We found the Mürzsteg region as the most likely source population for introductions to the Czech Republic and New Zealand, supplemented with close association with sequences from Ebensee in populations from the Czech Republic. Genetic diversity present in the Czech Republic was further relocated to the introduced populations in Slovakia in the 1960's.

Abundances of the common hamster in western Europe declined dramatically over the last 30 years. Recently, severe restrictions in distribution range have also been reported from central European countries. Here we update knowledge of the hamster distribution range in the Czech Republic based on information from six independent sources: (1) monitoring programme for the common vole carried out by State Phytosanitary Administration, (2) monitoring carried out directly by us, (3) questionnaire data from farming companies, (4) questionnaire data from district museums, (5) data from a public server BioLib for mapping species distribution, and (6) observations from nonrelated research activities and persons taking interest in hamsters. The comparison of locations detected after 2000 with those from the last survey > 30 years ago suggests that the range is severely reduced with hamsters retreating to the optimum lowland habitats along large rivers. These results suggest that the demographic mechanisms causing population decline in western populations operate in central Europe as well.

We combined mitochondrial (cyb, control region, coi, nd4) and nuclear (irbp, ghr, sry, lcat) DNA sequence data to infer phylogenetic relationships of arvicoline voles. The concatenated supermatrix contained 72.8 % of missing data. From this dataset, Bayesian inference showed close relationships of Arvicola and Chionomys, Proedromys with Lasiopodomys and Microtus gregalis, Phaiomys with Neodon and M. clarkei. Genus Microtus formed a supported group with Blanfordimys and N. juldaschi. The gene partition taxon sets were explained in the multilocus phylogeny in such a way that the resulting Bayesian inference tree represented a unique solution on a terrace in the tree space. This means that although the supermatrix contained a large proportion of missing data, it was informative in retrieving a phylogeny with a unique optimality score, tree likelihood.

The taxonomy and distribution of rodents in Zambia was comprehensively summarized in 1978 by W.F.H. Ansell in his excellent book Mammals of Zambia. Despite the fact that during the last three decades many new taxonomic revisions of African rodents were published and extensive new material collected, not much work has been done on Zambian rodents since the book publication. Here we summarize the current knowledge of one of the most speciose group of African rodents, the tribe Praomyini, in Zambia. We review available historical records and revise our recently collected material by sequencing the mitochondrial DNA gene of cytochrome b. The presence of eight species of Praomyini in Zambia is documented and the pattern of their geographical distribution is described and discussed. Two species, Praomys minor and Mastomys coucha, are reported for the first time from Zambia and Praomys cf. jacksoni probably represents a new undescribed species. On the other hand, the actual occurrence of Colomys goslingi, known in Zambia only from one historical record, is questionable. The results document the usefulness of the DNA barcoding approach for description of species diversity of taxonomically complicated groups with many cryptic species.

We analyzed sequences of two variable segments of the mitochondrial control region (CR) and flanking regions in the house mouse (Mus musculus). Most of the material was sampled from the eastern Mediterranean and the Middle East, i.e., a source area for the colonization of Europe. These sequences were supplemented with other samples from the whole range of the species including the Yemeni island of Socotra. This island was shown to harbour mice bearing M. m. domesticus and M. m. castaneus CR haplotypes. In addition, we found 10 distinct sequences at the same locality that were markedly different from all known CR sequences. Sequencing of the whole mitochondrial genome suggested these sequences to represent nuclear fragments of the mitochondrial origin (numts). We assessed genetic variation and phylogeography within and among the house mouse subspecies and estimated the substitution rate, coalescence times, and times of population expansion. We show the data to be consistent with time dependency of substitution rates and recent expansion of mouse populations. The expansion of European populations of M. m. musculus and M. m. domesticus estimated from the CR sequences coincide with presumed time of colonization of the continent in the Holocene.

Despite the long-term study of the house mouse hybrid zone in Europe knowledge of its course in some areas is still rather vague. Comparisons of different portions of the zone showed some common patterns, however, several discordances were also revealed, the most remarkable being introgression of the Y chromosome. We sampled mice along the presumed course of the secondary contact zone between two subspecies, Mus musculus musculus and M. m. domesticus, from Schleswig-Holstein to southern Bavaria, in order to localize more precisely its position. A second aim was to reveal whether introgression shows some general rules obscured until now by studies of geographically isolated transects of the zone. We employed maternally (mtDNA), paternally (Y), and biparentally inherited markers and related their introgression patterns to the hybrid index (HI) based on five X-linked loci. While transition of autosomal loci across the zone was congruent with changes in HI, mtDNA showed bidirectional introgression with alien alleles occurring far behind the zone. Finally, the Y chromosome displayed asymmetric unidirectional introgression of the musculus type into domesticus background. We discuss evolutionary forces shaping these patterns.

House mice are believed to be, unlike rats, only reluctant swimmers. If water is a barrier to mouse dispersal water bodies and streams can have a substantial impact on the genetic structure of populations. Previous studies revealed influence of rivers on the position and structure of the European hybrid zone between two house mouse subspecies, Mus musculus musculus and M. m. domesticus. In this study, we used a simple motivation experiment to test the disposition of both wild and inbred mice representing the subspecies to overcome a water barrier. As the more dispersing sex, males were chosen for the experiment. Mice were tested under two air/water temperature regimes, 20 °C and 10 °C. Contrary to a common belief tested animals entered water rather easily, often even engaging in repeated swimming. We found significant differences in scored behavioural parameters between the subspecies. Under the 20 °C regime, both wild and inbred domesticus males entered and crossed the water earlier and more often swam even when satiated. Strikingly, under the 10 °C regime, the results were rather equivocal but with the opposite tendencies, with musculus males being more willing to swim. We discuss implications of these findings for the hybrid zone dynamics.

Despite abundant knowledge about the relationship between body size (i.e., body mass, lower limb length) and limb posture during locomotion on the level of interspecies variability, little is known about variation on the intraspecific level. We used an experimental approach to evaluate the relationship between body size and knee posture during walking in humans at specific gait events and at each percentage point of normalized stance phase. We detected significant negative correlation between knee flexion angle and body mass at the second peak of the vertical ground reaction force, but, in contrast to a previous study, we found no significant relationship between knee flexion angle and lower limb length. Although not significant, strengthened correlations between knee flexion angle and lower limb length were detected at late stance phase and these coincide well with the strengthened correlations between knee flexion angle and body mass. Our findings support the view that body size influences limb posture during locomotion even on the intraspecific level. In humans, larger individuals tend to use more extended knee postures in late stance of walking than do smaller individuals.

Digitization of periosteal and endosteal contours of bone cross section is one of several methods used for calculating long bone cross-sectional geometry (CSG). In this study, invasively obtained bone histological samples were used to calculate intra-observer measurement error for CSG parameters. Intra-observer error was measured based upon repeated measurements of cross-sectional areas (total area [TA], cortical area [CA]) and moments of area (I_max, I_min, I_max/I_min, J) in B6CBA mice (n = 17). Cross sections were cut at 50 % of the biomechanical length of the left tibia and the samples were further processed for CSG and histological analysis. Intra-observer error was measured to estimate the accuracy of the digitization method. Accuracy of the tested digitization method was expressed by mean difference (MD), mean absolute difference (MAD), and limits of agreement (LA). The results confirm our assumption that intra-observer error decreases with the number of repeated measurement events. Thus, the error can be minimized by acquiring experience in the section digitizing. Our results also show that TA, CA and polar moment of area (J) are more susceptible to intra-observer error than are I_max, I_min and I_max/I_min.