Combined phylogenetic analysis of a new North American fossil species confirms widespread Eocene distribution for stem rollers (Aves,Coracii)

We report a nearly complete skeleton of a new species of stem roller (Aves, Coracii) from the early Eocene Green River Formation of North America. The new species is most closely related to two species‐depauperate lineages, Coraciidae (rollers) and Brachypteraciidae (ground rollers), that form a monophyletic crown clade (Coracioidea) with an exclusively Old World extant distribution. Phylogenetic analysis utilizing a matrix of 133 morphological characters and sequence data from three genes (RAG‐1, c‐myc, and ND2) identifies the new species as a stem member of the Coracii more closely related to the crown clade than the only previously identified New World taxon, Primobucco mcgrewi. The phylogenetic placement of the new species and Primobucco mcgrewiindicates a widespread northern hemisphere distribution in the Eocene with subsequent restriction to Africa, Madagascar, Australia, and temperate to tropical parts of Europe and Asia. It provides evidence of further ecological diversity in early stem Coracii and convergence on crown morphologies. The new species contributes to mounting evidence that extant distributions for major avian subclades may be of comparatively recent origin. Further late Palaeogene sampling is needed to elucidate potential drivers for shifting avian distributions and disappearance of Coracii from North America. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157 , 586–611.     

Contribution of cyclic parthenogenesis and colonization history to population structure in Daphnia

Cyclic parthenogenesis, the alternation of parthenogenetic and sexual reproduction, can lead to a wide scope of population structures, ranging from almost monoclonal to genetically highly diverse populations. In addition, sexual reproduction in aquatic cyclic parthenogens is associated with the production of dormant stages, which both enhance potential gene flow among populations as well as impact local evolutionary rates through the formation of dormant egg banks. Members of the cladoceran genus Daphnia are widely distributed key organisms in freshwater habitats, which mostly exhibit this reproduction mode. We assessed patterns of genetic variation within and among populations in the eurytopic and morphologically variable species Daphnia longispina , using data from both nuclear (13 microsatellite loci) and mitochondrial (partial sequencing of the 12S rRNA gene) markers from a set of populations sampled across Europe. Most populations were characterized by very high clonal diversity, reflecting an important impact of sexual reproduction and low levels of clonal selection. Among-population genetic differentiation was very high for both nuclear and mitochondrial markers, and no strong pattern of isolation by distance was observed. We also did not observe any substantial genetic differentiation among traditionally recognized morphotypes of D. longispina . Our findings of high levels of within-population genetic variation combined with high among-population genetic differentiation are in line with predictions of the monopolization hypothesis, which suggests that in species with rapid population growth and potential for local adaptation, strong priority effects due to monopolization of resources lead to reduced levels of gene flow.     

Haemoglobin concentration and body condition of nestling Great Tits Parus major : a comparison of first and second broods in two contrasting seasons

The physiological condition of nestling altricial birds depends on the quantity and quality of food delivered to them by parents. One indicator of the condition of Great Tit Parus major nestlings is the haemoglobin concentration in their blood. The present study demonstrates the influence of weather conditions (temperature and rainfall) on nestling haemoglobin concentrations during two consecutive breeding seasons in two different habitat types (parkland vs. woodland) in the city of Łódź in Central Poland. This influence probably results from the effects of weather on the trophic base of the Tits. Dry, hot weather strongly affected bush and herbal foliage later in the breeding season (mid-June to mid-July) in 2006, presumably by interfering with the development of herbivorous arthropod populations. This in turn caused food shortages for second broods of Great Tits, which resulted in nestlings having low haemoglobin levels. In the following year, temperature was on average lower, and rainfall was regular but not very heavy. These conditions enabled the development of arthropod assemblages, and the trophic base for birds was much richer. Haemoglobin concentrations in the blood of nestlings from second broods were significantly higher than those of first broods and, unexpectedly, second-brood nestlings in 2007 were on average in better physiological state than first-brood nestlings in 2006 in both habitats. The relationship between haemoglobin concentration, brood category and year was very similar to that for nestling body mass. However, it was independent of both body mass and brood size. In some years and under certain conditions, second broods can be more successful than first broods.     

The challenges of conservation for declining migrants: are reserve‐based initiatives during the breeding season appropriate for the Pied Flycatcher Ficedula hypoleuca?

Creating conservation policies for declining migrant species in response to global change presents a considerable challenge. Migrant species are affected by factors at breeding grounds, overwintering areas and during migration. Accordingly, reserve-based management during the breeding season is not always a suitable conservation strategy. Recent Pied Flycatcher population decline typifies the pattern for many migrants. The UK population has declined by 43% in the past decade, but explanations, and possible solutions, remain elusive. We use 15 years of data (1990–2004) from a declining British population to establish possible reasons for decline, considering: (1) breeding performance (including the influences of competition and predation); (2) weather patterns caused by the winter phase (December–March) of the North Atlantic Oscillation (NAO), which modify conditions experienced at wintering grounds and on migration; and (3) possible impacts of climate change on spring temperatures. We conclude that decreasing breeding performance is contributing to decline, but that non-breeding factors are more important. Winter NAO index is a strong predictor of breeding population, probably because it influences food abundance in Africa and at migratory stopover points. Importantly, however, year itself enhances the predictive model, indicating that influences on population remain unaccounted for by current research. Management strategies based on increasing breeding productivity cannot fully address population decline because non-breeding factors appear important. However, as breeding performance is declining, breeding-based strategies remain useful conservation tools. To this end, our research indicates that optimal placement of nestboxes as regards orientation and habitat management to increase larval food supplies could increase productivity significantly.     

The change in genetic diversity down the core‐edge gradient in the eastern spadefoot toad (Pelobates syriacus)

Several hypotheses are available to predict change in genetic diversity when approaching peripheral populations. We used the eastern spadefoot toad in Israel as a model system to examine these hypotheses using population genetics analyses and network theory. Our results contradicted most of the predictions from the ‘abundant centre’ model, that edge populations should have lower density and lower genetic diversity than core populations. Furthermore, dispersal rate between core and peripheral populations is expected to be asymmetric, mostly directed outwards from the core population, but we did not detect such a trend. Our data did not support the hypothesis of no change or a non‐linear change in genetic diversity towards the range edge. However, our results did fit the Fisher (The Genetical Theory of Natural Selection, Clarendon Press, Oxford, 1930) hypothesis, which predicts increase in genetic variability from core to edge of distribution. We attributed this finding to the much harsher climatic and abiotic conditions at the edge, which must be tolerated over generations by both tadpoles and post‐metamorphic individuals in this region. Finally, our results have significant conservation implications for the survival of this species in Israel, where it is critically endangered. We identified two distinct communities, which are genetically linked through two specific rain pools in the Upper Galilee. Details on the spatial subdivision of this species are cardinal for future management and restoration of temporary wetlands in Israel.     

On the rate of budding and proximal attenuation of the graptoloid rhabdosome

Earlier models of the morphogenesis in graptoloid colonies can be improved by taking into account the rate of growth and budding. It is assumed that both these factors are controlled by a specific function of the morphogen, here called for convenience the blastogen , and both are responsible for the attenuation of the proximal part of the rhabdosome. The permanence of this attenuation may theoretically be explained by the universal advantage of differentiation between the proximal and the distal part of the colony. Some aspects of possible adaptive significance of such colony organization are discussed. □ Graptoloid colonies, morphogenesis, mathematical model.     

Serotypic Variation Among Isolates of Ichthyophthirius multifiliis Based on Immobilization

Efforts have been made to determine whether surface antigens could be used as biochemical markers to define strain differences in the parasitic ciliate Ichthyophthirius multifiliis. In previous studies, a wild-type isolate designated G1 was found to have surface proteins analogous to the immobilization antigens of Paramecium and Tetrahymena; rabbit antiserum against this strain immobilizes homologous cells in vitro. It has now been shown for two additional Ichthyophthirius isolates (designated G1.1 and G2) that immobilization antigens are both present and serologically distinct. Proteins of similar size, which cross-react in Western blots with rabbit antisera against immobilization antigens of the G1 strain, are nevertheless found in the G1.1 and G2 isolates. As shown by Southern blotting analysis, the G1.1 and G2 strains also contain genomic DNA sequences which hybridize with an immobilization antigen cDNA from G1 when probed under conditions of reduced stringency. The serotypic differences in immobilization between I. multifiliis isolates appear to be stable over time and provide a means of discriminating strains. In addition to providing a basis for comparative studies, the work described here has implications for the development of vaccines against this important fish parasite.     

Physical and biological conditions on a steep intertidal gradient at Rottnest Island,Western Australia

Seven species of grazing molluscs, two littorinids, one nerite, three limpets and one chiton, lived on the vertical intertidal rock wall at the landward edge of the coastal limestone platforms at Rottnest Island, Western Australia. On the average, the vertical ranges of these species overlapped broadly, although a consistent zonation pattern was conspicuous from the platform surface upwards for 2 m. On these vertical intertidal shores, physical and biological conditions were predicted quantitatively from easily made measurements of vertical height on the shore; the percentage of time any shore level was immersed in seawater, the percent weight loss of plaster clods, the standing crop of algae, and the growth rate of the limpet, Notoacmea onychitis, all decreased linearly or semi-logarithmically with increasing height on the shore. The standing crop of animals was greatest, largely due to the presence of the chiton, between 40 and 70 cm from the platform surface and decreased rapidly down the shore and more gradually towards higher shore levels. We interpret this information and the positive correlation between algal production rate, and egestion rate of the animal community at various levels of the shore as evidence supporting the idea that food may be in short supply on these shores.