A molecular approach to the phylogenetic relationships of the western palaearctic Helicoidea (Gastropoda: Stylommatophora)

Molecular phylogenetic relationships among 45 members of the Helicoidea (Gastropoda: Stylommatophora) were examined using partial mitochondrial 16S rRNA sequences. Phylogenetic relationships were inferred using maximum parsimony, maximum likelihood and Bayesian methods. The reconstructed phylogenies showed a good degree of support for more recent branches, but gave little support to deeper nodes. Mitochondrial rDNA data further confirmed monophyletic status of helicids, recognized monachine hygromiid and bradybaenid clades and resolved a number of relationships in the helicelline hygromiids. With the respect to the latter assemblage, most of the anatomically based groups are confirmed, corroborating the diagnostic value of the dart-sac complex and a close affinity between Ichnusomunda sacchii and species of the genus Cernuella . Nevertheless, some well resolved branches challenge previous systematic arrangements, grouping species previously placed in different arrangements. In particular, support was not found for the monophyly of helicelline hygromiids with pedal penial innervation. Possible explanations for these incongruencies are suggested. 16S sequence data are appropriate for studies of relationships within the different species groups and less so for recovery of more ancient radiations in the Helicoidea. It will be valuable to combine the 16S data with other gene sequences to estimate basal relationships.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 501–512.     

Does Management for Duck Productivity Affect Songbird Nesting Success?

ABSTRACT Habitat management for ducks has significantly influenced prairies and wetlands used by other species. However, the effects of management on other species have not been clearly assessed. We present the first study to compare the nesting success of ducks with the productivity of coexisting passerines. We evaluated effects of cattle grazing, subdivision of fields, habitat edges, year, and vegetation structure on duck and songbird nesting success in 32 mixed-grass prairie fields in southern Alberta, Canada. Duck and songbird nesting success were not correlated. Duck nesting success was influenced by timing of grazing and vegetation structure, and tended to be higher in wetter years, whereas nesting success of most songbirds was not influenced by vegetation structure or grazing, and was sometimes higher in drier years. Local habitat management for ducks cannot be assumed to benefit songbirds. However, some management strategies, such as those that promote tall grass and short litter, might benefit both taxa.     

Characterization of 18 SNP markers for sperm whale (Physeter macrocephalus)

We report the characterization of 18 new single nucleotide polymorphism (SNP) markers for an endangered species, the sperm whale (Physeter macrocephalus), developed using a targeted gene approach. SNP markers were derived from autosomal regions of the genome using primers originally characterized for genome mapping in other mammals. These SNP markers are the first to be designed for genotyping sperm whale populations and will provide a necessary addition to the genetic tools employed for understanding population structure on a global scale and for developing a conservation management strategy for this endangered species.     

Genetic variation for the rate of recruitment of novel insect prey into the diet of a bird

Two lines of quail (Cotumix coturnix japonicus) were selected over three generations for the speed of their response to the red colour form of the two-spot ladybird beede (Adalia bipunctata), an aposematic, semi-palatable prey insect. One line was bred for fast recruitment of die new prey into the diet and die odier for slow recruitment. Differences between the lines suggested additive genetic variation. The birds' response to insect prey with different colour patterns and toxicities (brown beetles, green butterfly pupae, melanic two-spot ladybirds and toxic seven-spot ladybirds) demonstrated that die selection involved a specific response to novel prey. The results are discussed in relation to predator strategy and the evolution of aposematism.     

Differences between the 7-spot and 2-spot ladybird beetles (Coccinellidae) in their toxic effects on a bird predator

Abstract. 1. Experiments with nestling blue tits Parus caeruleus L. examined the effects of feeding them 7-spot ladybird Coccinella septempunctata (L.), 2-spot ladybird Adalia bipunctata (L.) or controls Tenebrio sp.
2. A feeding rate of 51/3 7-spot ladybirds per day 'killed' nestlings within 2 days. Three of six nestlings fed at half this rate survived 4 days. In contrast, all experimental birds survived sixty-four 2-spot ladybirds fed over 4 days (equivalent by weight to the high 7-spot diet).
3. Nestlings fed 7-spot ladybirds also grew more slowly than birds fed 2-spot ladybirds. The latter birds showed no difference in weight gain from the controls although they begged more strongly for food.
4. Cadavers of birds fed 7-spot ladybirds showed evidence of severe liver damage.
5. The results indicate a substantial difference between the ladybird species in their toxicity to nestling blue tits. They support the hypothesis that 2-spot ladybirds are largely-edible, polymorphic Batesian mimics of well-protected, monomorphic species such as the 7-spot ladybird.     

Ionic Resistance in Strains of the Tetrahymena pyriformis Complex1

ABSTRACT. Strains of Tetrahymena thermophila were examined in an attempt to establish what role certain ions (Na⁺, K⁺, Li⁺, Ba⁺⁺, Ca⁺⁺, Mg⁺⁺, Mn⁺⁺, Al⁺⁺⁺, Fe⁺⁺⁺) play in influencing cell survival time in a culture medium. In short-term experiments (20–30 min), cell survival time in a 1% peptone medium is directly related to the valence of the ion employed. Long-term observations (lasting up to five days) in a 1% peptone medium containing lower ion concentrations revealed that the effects on cell-cycle time are not correlated with the valence state of the ion. Comparisons were made among the ionic resistances of strains of T. thermophila, of T. pyriformis sensu stricto, and of two subspecies of T. pigmentosa. Strains within a species are highly correlated in their patterns of ionic response, while marked differences between species occur. The most distinctive group of strains examined came from one of the subspecies (syngen 6) of T. pigmentosa.     

Multiple Allelic Variation in a Sodium Channel Gene from Populations of Australian Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) Detected via Temperature Gradient Gel Electrophoresis

Helicoverpa armigera , the cotton bollworm; is a significant pest of Australian field and vegetable crops and has a widespread incidence of resistance to pyrethroid insecticides. Naturally occurring variation in the para sodium channel gene was assayed in H. armigera. the polymerase chain reaction (PCR) was used to amplify part of the gene and temperature gradient gel electrophoresis (TGGE) used to detect differences in the melting properties of the amplified DNA fragments. A gene fragment of approximately 890 bp was characterised in a total of 66 individuals, comprising four sample groups: untreated controls and fenvalerate-treated individuals from both the Namoi valley, NSW and the St. George irrigation area, Qld. At least sixteen alleles were detected for the 3'-end, 250 bp, Hpall digest fragment of the amplified part of the gene. the Namoi and St. George allele distributions were significantly heterogeneous, making this locus a suitable marker for use, with others, in migratory studies among H. armigera populations. Since this gene is a candidate for pyrethroid resistance in the related American pest Heliothis virescens (F.) we looked for a difference in allele distributions between insecticide treated and untreated groups. No association between molecular variation in this gene and fenvalerate resistance was detected.     

Mating-Type Dependent Cell Pairing in Oxytricha hymenostoma. III. Chromatin Mixing After Macronuclear Fusion*

SYNOPSIS. Mating-type dependent cell pairing in Oxytricha hymenostoma was studied by both light autoradiography and transmission electron microscopy. The process results in the macronuclear bodies of the 2 partners fusing completely with each other 2 by 2. In each fusion the 2 chromatin masses, easily distinguishable from each other for the first 6 h of the pairing, progressively intermingled and underwent a sort of rearrangement so that they eventually acquired a uniform pattern. The possible mechanisms regulating macronuclear fusion and DNA amount in the daughter cells are discussed.     

New biostratigraphical constraints for the Norian/Rhaetian boundary: data from Lagonegro Basin,Southern Apennines,Italy

Giordano, N., Rigo, M., Ciarapica G. & Bertinelli A. 2010: New biostratigraphical constraints for the Norian/Rhaetian boundary: data from Lagonegro Basin, Southern Apennines, Italy. Lethaia. 10.1111/j.1502‐3931.2010.00218.x. Four stratigraphic sections belonging to Lagonegro succession (Southern Apennines) at Mt S. Enoc, Pignola‐Abriola, Sasso di Castalda and Mt Volturino have been studied in detail under to provide a new micro‐palaeontological data set based on conodonts and radiolarians for the characterization of the Norian/Rhaetian interval. The studied sections represent the different settings of the Lagonegro Basin (from proximal to distal facies) and permit a detailed, integrated, biostratigraphy of the Calcari con Selce (cherty limestones) and Scisti Silicei formations (bedded cherts with radiolarians) to be drawn up. The upper portion of the Calcari con Selce Formation, exhibits intermediate characteristics between the Calcari con Selce and Scisti Silicei Formation, in particular the progressive decrease in carbonate content against an increase in shales and cherts. Within the four sections studied, the Norian/Rhaetian interval has been documented both with conodonts and radiolarians. Because of the continuity and the absence of condensed facies, it has been possible to recognize the morphocline between species Misikella hernsteini and Misikella posthernsteini, here represented by all the transitional forms characterized by common features between the two species, gathered in three evolutionary steps. Moreover, the morphocline between M. hernsteini and M. posthernsteini has been involved in the definition of the Norian/Rhaetian Boundary, recognizing thus the FAD of M. posthernsteini, one of the possible biomarkers proposed for the boundary. The rich, well‐preserved, radiolarian associations of Pignola‐Abriola, Sasso di Castalda and Mt Volturino permit the correlation of Tethyan and American conodont successions, highlighting the importance of the mostly coincident occurrences of M. posthernsteini and Epigondolella mosheri morphotype A, which correspond to the base of Proparvicingula moniliformis A. Z. and the disappearance of bivalve Monotis. These coincident bioevents are used here to define the base of the Rhaetian stage. □Biostratigraphy, conodonts, Lagonegro Basin, Late Triassic, Norian/Rhaetian boundary, radiolarians.     

Invasion patterns across multiple scales by Hieracium species over 25 years in tussock grasslands of New Zealand's South Island

Studying patterns of species invasions over time at multiple spatial scales may help us to elucidate important factors driving those patterns and how they change according to temporal or spatial resolution. Here we provide a large, long‐term, landscape‐scale study of the invasion of three Hieracium species using a dataset that encompasses vegetation change on 124 transects over 25 years across the lower eastern South Island of New Zealand. We investigated the relationships between key environmental and ecological factors and the invasion trajectories of H. lepidulum, H. pilosella and H. praealtum, at two spatial scales: (i) among‐transect colonization and (ii) within‐transect changes in frequency and per cent cover. Our results show that the colonization and spread of Hieracium species among and within transects reflect (i) the importance of initial environmental and biological conditions, (ii) that our sampling captured different periods of the invasion trajectories of each of the three species, and (iii) the effects of differences in life histories of the three species.