The plot thickens: does low density affect visitation and reproductive success in a perennial herb, and are these effects altered in the presence of a co-flowering species?

Plants may experience reduced reproductive success at low densities, due to lower numbers of pollinator visits or reduced visit quality. Co-occurring plant species that share pollinators have the potential to facilitate pollination by either increasing numbers of pollinator visits or increasing the quality of visits, but also have the potential to reduce plant reproductive success through competition for pollination. I used a field experiment with a common distylous perennial (Piriqueta caroliniana) in the presence and absence of a co-flowering species (Coreopsis leavenworthii) in plots with one of four different distances between conspecific plants. I found strong negative effects of increasing interplant distance (related to conspecific density) on several components of P. caroliniana reproductive success: pollinator visits to plants per plot visit, visits received by individual plants, conspecific pollen grains on stigmas, outcross pollen grains on stigmas, and probability of fruit production. Although P. caroliniana and C. leavenworthii share pollinators, the co-flowering species did not affect visitation, pollen receipt or reproductive effort in P. caroliniana. Pollinators moved very infrequently between species in this experiment, so floral constancy might explain the lack of effect of the co-flowering species on P. caroliniana reproductive success at low densities. In co-occurring self-incompatible plants with floral rewards, reproductive success at low density may depend more on conspecific densities than on the presence of other species.     

Genetic structure and gene flow in French populations of two Ostrinia taxa: host races or sibling species?

Most models of ecological speciation concern phytophagous insects in which speciation is thought to be driven by host shifts and subsequent adaptations of populations. Despite the ever-increasing number of studies, the current evolutionary status of most models remains incompletely resolved, as estimates of gene flow between taxa remain extremely rare. We studied the population genetics of two taxa of the Ostrinia genus--one feeding mainly on maize and the other on mugwort and hop--occurring in sympatry throughout France. The actual level of divergence of these taxa was unknown because the genetic structure of populations had been investigated over a limited geographical area and the magnitude of gene flow between populations had not been estimated. We used 11 microsatellite markers to investigate the genetic structure of populations throughout France and the extent of gene flow between the two Ostrinia taxa at several sites at which they are sympatric. We observed clear genetic differentiation between most populations collected on the typical respective hosts of each taxon. However, populations displaying intermediate allelic frequencies were found on hop plants in southern France. Individual assignments revealed that this result could be accounted for by the presence of both taxa on the same host. Gene flow, estimated by determining the proportion of hybrids detected, was low: probably<1% per generation, regardless of site. This indicates that the two Ostrinia taxa have reached a high level of genetic divergence and should be considered sibling species rather than host races.     

Native or not? Tracing the origin of wild-caught and captive freshwater turtles in a threatened and widely distributed species (Emys orbicularis)

Pet and food trade are among the major threats for many chelonians species worldwide. We investigate the impact of the present and past trade in European pond turtles (Emys orbicularis, E. trinacris) on their extant distribution pattern. Using a comprehensive mtDNA dataset of cytochrome b haplotypes derived from more than 1,550 individuals, we assigned wild-caught allochthonous and captive turtles from six European countries to their native regions across the entire distribution range. We found allochthonous haplotypes in all countries surveyed, providing evidence of long-distance translocations owing to past and present trade, illegal poaching or collection by tourists. In summary, we identify source regions of allochthonous turtles and past and present trade routes. Moreover, we point out future directions which would contribute to conservation and management of these threatened species.     

Why pigs are important in Papua? Wealth,height and reproductive success among the Yali tribe of West Papua

Many studies have investigated how different variables influence the reproductive success (RS) in the populations of natural birth control. Here, we tested hypotheses about positive relationship between wealth, height and several measures of RS in an indigenous, traditional society from West Papua. The study was conducted among the Yali tribe in a few small, isolated mountain villages. In this tribe, a man's wealth is measured by the number of pigs he possesses. We found that wealth was related to fertility and number of living children, but not to child mortality in both men and women. Additionally, child mortality increased with the number of children in a family. Finally, we did not observe any relationship between height and reproductive success measures or wealth. We provide several possible explanations of our results and also put forward hypothetical background for further studies of indigenous populations.     

Quantitative evaluation of common polymorphism (rs1801282) in the PPARγ2 gene and hypertension susceptibility

The peroxisome proliferator-activated receptor-γ2 (PPARγ2) gene has been implicated in the etiology of hypertension. However, the results have been inconsistent. In this study, a meta-analysis was performed to assess the association of PPARγ2 rs1801282 polymorphism with hypertension risk. Published literature from PubMed, Embase databases, CNKI and Wanfang Data were retrieved. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed- or random-effects model. Eight studies (1865 cases and 1416 controls) for rs1801282 polymorphism were identified. The results suggested that rs1801282 polymorphism Ala allele might be protective for hypertension among East Asians (Ala/Ala+Pro/Ala vs. Pro/Pro: OR=0.63, 95%CI 0.46-0.86) but not among Caucasians (Ala/Ala+Pro/Ala vs. Pro/Pro: OR=0.72, 95%CI 0.38-1.38). The results indicated the significant association of PPARγ2 rs1801282 polymorphism with hypertension susceptibility among East Asians.     

Does a trade‐off between current reproductive success and survival affect the honesty of male signalling in species with male parental care?

Recent theory predicted that male advertisement will reliably signal investment in paternal care in species where offspring survival requires paternal care and males allocate resources between advertisement and care. However, the predicted relationship between care and advertisement depended on the marginal gains from investment in current reproductive traits. Life history theory suggests that these fitness gains are also subject to a trade‐off between current and future reproduction. Here, we investigate whether male signalling remains a reliable indicator of parental care when males allocate resources between current advertisement, paternal care and survival to future reproduction. We find that advertisement is predicted to remain a reliable signal of male care but that advertisement may cease to reliably indicate male quality because low‐quality males are predicted to invest in current reproduction, whereas higher‐quality males are able to invest in both current reproduction and survival to future reproduction.     

Responses of a rare (Viola elatior) and a common (Viola mirabilis) congeneric species to different management conditions in grassland — is different light competition ability responsible for different abundances?

We studied a congeneric species pair that shows very different abundances in Estonia — Viola elatior occurs in only five localities in mesic calcareous grasslands, while Viola mirabilis is abundant in mesic calcareous grasslands and forests all over the country. Both species were sown in patches of mesic calcareous grassland, in clipped and untreated plots. Both species were established successfully after sowing, indicating that they both may be dispersal limited to the same extent. V. elatior showed higher fecundity in the second year than V. mirabilis. V. elatior was more sensitive to the availability of light. In the first year, V. elatior established more successfully in clipped plots than V. mirabilis. In the second year, the number of established V. elatior individuals decreased in unmanaged plots, where competition for light was more severe. Since many calcareous grasslands in Estonia have been abandoned and the standing crop, as well as the cover of shrubs and trees, has increased, sensitivity to light competition may be one reason why V. elatior has become more rare. It cannot be the only reason for its rarity in the whole region, since many other grassland species that are vulnerable to reduced light in overgrown unmanaged grassland communities still occur in much higher numbers in the country. It was hypothesised that historical factors, e.g. relatively late arrival in the region, may also be behind the rarity of V. elatior.     

Flower or spikelet? Understanding the morphology and development of reproductive structures in Exocarya (Cyperaceae, Mapanioideae, Chrysitricheae)

Fundamental questions of floral morphology remain unresolved in the grasslike monocots in order Poales, including what constitutes a flower and what constitutes a spikelet. The mapaniid sedges have particularly complex spikeletlike structures, variously interpreted as clusters of flowers or spikelets. Recent phylogenetic studies of Cyperaceae have identified the mapaniid clade as sister to the rest of the family, but the homology of mapaniid reproductive units (RUs) and spikeletlike units (SLUs) to other sedge flowers and spikelets is unclear. We examined reproductive development in the mapaniid Exocarya sclerioides. Inflorescence branches terminated in a SLU with bracts and 1-4 RUs. RUs had four small leaflike structures (LLSs): two lateral LLSs, each associated with a stamen, an abaxial LLS associated with a stamen, and an adaxial LLS. The gynoecium terminated the RU. All RUs were axillary to bracts, and unexpanded bracts and RUs were produced beyond expanded RUs, so SLUs were racemose. RUs developed from a single primordium that initiated two lateral LLSs, then two lateral stamens, then the gynoecium. Initiation of the abaxial LLS and stamen and the adaxial LLS followed. We hypothesize that the RU is a sympodial branch that terminates in a hermaphroditic flower with two stamens and a gynoecium; the two lateral LLSs are halves of a deeply divided prophyll.     

How many species of Diacyclops? New taxonomic characters and species richness in a freshwater cyclopid genus (Copepoda,Cyclopoida)

The genus Diacyclops Kiefer, 1927 emend. Morton (1985) includes more than 100 species, widely distributed in all kinds of freshwater environments, and is the richest genus in the family Cyclopidae. Traditionally, Diacyclops species were defined according to differences in a few morphological characters; some characters (number of antennulary segments, segmentation pattern of swimming legs) are useful only in the separation of species groups, others (length of caudal rami and caudal setae) are highly variable even within the same population. During the study of the D. languidoides-group, minute morphological characters were used to differentiate between species (spinulation pattern and setation of antennary basis, setation and aesthetasc shape of male antennule, setation of mandibulary palp and maxilliped, shape of leg 4 basis) which allow to identify several valid species up to now concealed under the name `Diacyclops languidoides' (Lilljeborg, 1901). The coexistence of up to six congeneric species in the same sampling area: (a) supports the validity of the proposed taxonomic characters, (b) demonstrates that species richness may be highly underestimated in freshwater cyclopoid assemblages in absence of good taxonomic practice; and (c) requires an ecological explanation of species coexistence. The role of morphologically based taxonomy in order to solve general problems of distributional ecology and theoretical biology is explored.     

Sequence and expression of an α-amylase gene in four related species of prickleback fishes (Teleostei: Stichaeidae): ontogenetic,dietary, and species-level effects

Partial α-amylase gene sequences were determined and α-amylase gene expression was quantified in four species of carnivorous, omnivorous, and herbivorous prickleback fishes (family Stichaeidae) to assess the effects of ontogeny, diet, and species on expression of this gene. Pairwise comparison of α-amylase nucleotide sequences revealed 96–98 % identity, and comparison of amino acid portions revealed 93–95 % similarity among the four prickleback species. Expression was determined using in situ hybridization and intensity of expression quantified using image analysis. Alpha-amylase expression level was compared in three feeding categories of the four species: (1) small, wild-caught carnivorous juveniles; (2) larger, wild-caught juveniles of the carnivorous species and the three that had shifted to herbivory or omnivory; and (3) larger, juveniles produced by feeding a low-starch artificial diet to small juveniles until they reached the size of the larger wild-caught juveniles. The results showed no dietary effect in any species but significant ontogenetic and species-level effects in Cebidichthys violaceus, as well as in the sister species Xiphister mucosus and X. atropurpureus. Based on a phylogeny for the Stichaeidae produced for this study using two mtDNA genes and one nuclear gene, the ontogenetic dietary shifts to herbivory/omnivory evolved independently in C. violaceus and in the clade containing the two species of Xiphister. All three of these species increased α-amylase gene expression with increase in size and had higher expression than Anoplarchus purpurescens, which is a member of a third, stichaeid clade comprising carnivores. These results show the importance of α-amylase in the herbivores and omnivores.     

Effects of ferric soils on arthropod abundance and herbivory on <Emphasis Type="Italic">Tibouchina heteromalla</Emphasis> (Melastomataceae): is fluctuating asymmetry a good indicator of environmental stress?

High concentration of heavy metals in the soils represents an important factor of physiological stress that influences the normal functioning of plants through oxidation processes, and negatively affects insect performance and leaf consumption by herbivorous insects. One useful indicator to evaluate environmental stress in plants by heavy metals and herbivory is the fluctuating asymmetry, which describes the random differences in size or shape between the two sides of a bilateral character in organisms and it is a widely used measure of developmental instability in plants. We evaluated under natural conditions, the effects of variation of heavy metals in the soils on herbivore patterns, fluctuating asymmetry and arthropod abundance in Tibouchina heteromalla in rupestrian grasslands along the Espinhaço chain in Brazil. We selected two study areas, the first characterized by the presence of soils with low concentration of heavy metals (quartzite soils). In the second area, the soils are characterized by the presence of high concentration of heavy metals such as iron (ferric soils). We found that leaf thickness was higher in ferric soils than in quartzite soils. Conversely, total leaf area was greater in quartzite soils in comparison to ferric soils. Plants in soils with heavy metals had both lower herbivory levels and arthropod abundance than plants in soils with low concentrations of heavy metals. Fluctuating asymmetry levels were significantly greater in individuals from quartzite soils compared to individuals from ferric soils. Herbivory was positively related with individual fluctuating asymmetry in quartzite soils. Our results suggest that T. heteromalla presents tolerance to soils with heavy metals suggesting an acclimatization to these environmental conditions, and therefore, ferric soils may not represent a factor of environmental stress.     

Does reproductive success increase with age or with size in species with indeterminate growth? A case study using sand lizards (Lacerta agilis)

Most data on determinants of reproductive success (RS) and reproductive tactics are correlational in nature, and hence cannot be used to infer causation. Consistent patterns-such as an increase in RS with age, as seen in many types of organisms-may result from diverse underlying mechanisms. Ontogenetic increases in RS in mammals and birds may be due largely to direct effects of age (via learning, etc.) but our analyses show that apparently analogous ontogenetic shifts in reproductive tactics and increases in RS in sand lizards (Lacerta agilis) are actually due to ontogenetic changes in body size. When size effects are removed, age exerts very little effect on either reproductive behaviour or RS in either sex. In many taxa, both age and body size may exert important effects on reproductive biology, and disentangling these effects should be a focus of further research.     

Effects of different methods and times of 17β-estradiol treatment on the feminization success in the narrow-clawed crayfish Astacus leptodactylus (Eschscholtz, 1823)

Sex differentiation is a profitable technique in crayfish aquaculture. Most of the studies have focused on sex differentiation in crayfish by ablation or implantation of androgenic glands. There is no research on sex differentiation using hormones in crayfish. In the present study, the effects of 17β-estradiol (E2) injections (10^?7 mol/crayfish) to females and baths (50 μg 17β-estradiol/L) to pleopodal eggs and stage1, 2, and 3 juveniles on the feminization of freshwater crayfish, Astacus leptodactylus were investigated. Results showed that E2 injection to females, bath to pleopodal eggs and bath to stage 1, 2, and 3 juveniles increased feminization rate significantly (p < 0.05) in comparison to the control in A. leptodactylus. Best feminization rate (male to female, 0.25:1) was observed after hormonal injection to the females combined with application of both for their both pleopodal eggs and stage 1, 2, and 3 juveniles. In conclusion, it is possible to obtain 75% females A. leptodactylus by E2 injection to females and bath to pleopodal eggs and stage 1, 2, and 3 juveniles. However, future studies are needed to investigate the mechanism of E2 in crayfish feminization and the sexual development of juveniles obtained from feminization.     

Occurrence of species of the genus Pityophthorus Eichhoff (Coleoptera,Curculionidae, Scolytinae) in?the?province of Quebec,Canada

Twig beetles in the genus Pityophthorus Eichhoff, 1864 include more than 300 species worldwide, with maximum diversity in tropical and subtropical regions. To date, approximately 50 species of Pityophthorus have been recorded in Canada, and these species are associated mainly with coniferous trees. Since 1981, no comprehensive study on this difficult taxonomic group has been conducted in Quebec, Canada, most likely due to their limited significance as forest pests. Based on data gathered from five years of field sampling in conifer seed orchards and compiled from various entomological collections, the distribution of Pityophthorus species in Quebec is presented. Approximately 291 new localities were recorded for the Pityophthorus species. Five species-group taxa, namely Pityophthorus puberulus (LeConte, 1868), Pityophthorus pulchellus pulchellus Eichhoff, 1869, Pityophthorus pulicarius (Zimmermann, 1868), Pityophthorus nitidus Swaine, 1917,and Pityophthorus cariniceps LeConte&Horn, 1876 were the most widespread. In contrast, Pityophthorus consimilis LeConte, 1878, Pityophthorus intextus Swaine, 1917, Pityophthorus dentifrons Blackman, 1922, Pityophthorus ramiperda Swaine, 1917, and Pityophthorus concavus Blackman, 1928 display a notably limited distribution. In addition, the first distribution records of Pityophthorus intextus and Pityophthorus biovalis Blackman, 1922 are furnished, and the subspecies Pityophthorus murrayanae murrayanae Blackman, 1922is reported from Quebec for the second time. Moreover, distribution maps are provided for all Pityophthorus species recorded in the province of Quebec.     

Paedomorphosis in two small species of toothed whales (Odontoceti): how and why?

To evaluate and assess the ontogenetic background for paedomorphosis in phocoenids, samples of 144 harbour porpoises, 81 white‐beaked dolphins, and 130 Commerson's dolphins were compared in terms of the development of epiphyseal fusion, cranial suture fusion, and ontogeny of cranial shape. Harbour porpoises and Commerson's dolphins terminated growth and development of all investigated traits sooner than white‐beaked dolphins, leading to lesser degrees of fusion of skeletal elements and less postnatal allometric development. The latter occurred even though shape in the two paedomorphic species developed at twice the rate relative to the size of white‐beaked dolphins. These observations imply that progenetic evolution has occurred convergently in phocoenid and Cephalorhynchus ancestors. The truncated ontogenies allow sexual maturity to be attained earlier and provide a greater reproductive potential. Both species inhabit similar temperate productive habitats and, hence, ecological factors are proposed to have supplied the selection pressures leading to progenesis. Constant prey availability must be a prerequisite for the observed phenomena because frequent food‐intake is necessitated by the limited capacity for energy storage and high heat‐loss entailed by the resulting small body sizes. Progenesis has rarely been proposed in mammal species. This may reflect rarity or that mammalian expressions of progenesis are less obvious. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 278–295.     

Does sex make a difference? Genetic diversity and spatial genetic structure in two co-occurring species of Gagea (Liliaceae) with contrasting reproductive strategies

Gagea lutea and G. spathacea are spring geophytes naturally co-occurring in woodlands, characterised by contrasting reproductive strategies probably caused by divergent ploidy levels. The hexaploid G. lutea relies on vegetative reproduction by subterranean bulbils in young stages but completely switches to sexual reproduction once a certain bulb size is attained. The nonaploid G. spathacea seems to be sterile and reproduces only vegetatively; the plants continue to form bulbils even in the rare event of flowering. This study used AFLP genotyping to investigate the consequences of these reproductive strategies for genetic diversity. For 150 and 100 samples from three Western Pomeranian populations of G. lutea and G. spathacea, respectively, AFLP fingerprints were analysed for three different spatial scales, the patch, the transect, and the region. Applying a threshold for genotypic identity of <0.05 simple matching distance, 22?C30 genets were detected in the three G. lutea populations, with all genets confined to single populations. Clonal genets consisted of 2?C9 samples and extended over up to 28?m, but never occupied the whole length of a transect; 67?C75% of all patches had different genets. Genetic distances between genets within populations were similar to those recorded between populations. Genotyping of G. spathacea revealed a single clonal genet for all three populations sampled within a distance of 30?km. The absent genetic diversity confirms the suspected sexual sterility. Gagea spathacea seems to be one of the few non-apomictic, fully clonal vascular plants able to occupy a significant range solely by dispersal of vegetative diaspores.     

Are periodic (intra-annual) tangential bands of vessels in diffuse-porous tree species the equivalent of flood rings in ring-porous species? Reproducibility and cause

Tree rings from ring-porous species have often been used as flood proxy. Many ring-porous species produce characteristic flood rings in response to stem submersion during vessel formation. Flood rings have earlywood vessels that are more numerous and/or of smaller cross-sectional area than “normal” rings. This study aimed at determining if diffuse-porous balsam poplar and trembling aspen, like ring-porous black ash, produce anatomically distinct annual tree rings in response to flooding. More specifically, we asked (i) if periodic tangential bands of vessels (hereafter PTBV) could be as easily identified/quantified as flood rings and (ii) if PTBV could be associated with spring flooding. Sampling of black ash, balsam poplar and trembling aspen trees took place along a flood exposure gradient in the floodplain of Lake Duparquet in northwestern Québec. Two observers recorded flood rings and PTBV. Consistency between observers was greatest when identifying flood rings. In both diffuse-porous species, PTBV occurred less abundantly than flood rings in black ash. They also occurred less often in balsam poplar than in trembling aspen. Years in which PTBV were initiated early in the growing season were associated with years in which flood rings occurred. Like flood rings, early occurring PTBV were more abundant in springs characterized by high mean river discharge, extensive snow cover, cold temperatures and heavy precipitation. Early-occurring PTBV dominated in flooded sites and late-occurring ones dominated in the control site. However, PTBV of the late-types were also observed in both flood exposures indicating that spring flood may not be the only factor modulating their formation. While flood rings seem to be associated with a change in the transport of growth regulators resulting from stem submergence and excess water, PTBV may be reflective of rhythmic alterations in the transport of growth regulators resulting from either water excess or deficit. Despite promising findings, many questions remain before PTBV in riparian diffuse-porous species can be widely used as a flood proxy. Why do species and individual trees differ in their ability to record them? What is the full range of environmental conditions triggering PTBV’s formation especially in unflooded sites and in the late growing season?