Home About us Contact
|
Home About us Contact | ||
|
|
||
Only Species (only + species)
Selected AbstractsOccurrence of Phytophthora species in oak stands in Italy and their association with declining oak treesFOREST PATHOLOGY, Issue 1 2002A. M. VETTRAINO Soil-borne species of Phytophthora were isolated from 19 of 30 examined oak forest areas in Italy. The frequency of isolated Phytophthora spp. (35.2%) was significantly correlated with soil pH and longitude of the sites. Eleven Phytophthora species were detected. Phytophthora cambivora, P. cinnamomi and P. cactorum were recovered from sites in central and southern Italy whereas P. quercina was isolated in the northern and central part of the country. Phytophthora citricola occurred all over Italy. Phytophthora quercina was the only species significantly associated with declining oak trees. Les Phytophthora dans les chênaies d'Italie et leur association avec les chênes dépérissants Des Phytophthora ont été isolés du sol dans 19 sites parmi 30 sites analysés dans des chênaies italiennes. La fréquence d'isolement de Phytophthora spp. (35,2%) était corrélée significativement avec le pH du sol et la longitude des sites. Onze espèces de Phytophthora ont été trouvées. Phytophthora cambivora, P. cinnamomi et P. cactorum ont été trouvés dans le centre et le sud de l'Italie et le P. quercina dans le nord et le centre. Phytophthora citricolaétait présent dans l'ensemble de l'Italie. Phytophthora quercinaétait la seule espèce associée significativement avec des chênes dépérissants. Vorkommen von Phytophthora Arten in Eichenbeständen in Italien und deren Bezug zu absterbenden Eichen Bodenbürtige Phytophthora Arten wurden in 19 von 30 untersuchten Eichenbeständen in Italien isoliert. Die Korrelationen zwischen der Häufigkeit der isolierten Phytophthora spp. und dem Boden pH sowie der geographischen Länge der Standorte waren statistisch signifikant. Phytophthora cambivora, P. cinnamomi und P. cactorum wurden an Standorten in Zentral- und Süditalien nachgewiesen, während P. quercina in Zentral- und Norditalien vorhanden waren. Phytophthora citricola kam in ganz Italien vor. Phytophthora quercina war die einzige Arte mit einer deutlichen Vergesellschaftung mit absterbenden Eichen. [source] Comparative activity pattern during foraging of four albatross speciesIBIS, Issue 1 2002Henri Weimerskirch The activity patterns of foraging Yellow-nosed Diomedea chlororhynchos, Sooty Phoebetria fusca, Black-browed D. melanophris impavida and Grey-headed Albatross D. chrysostoma were compared using loggers recording the timing of landing and take-offs, as well as the duration of bouts in flight or on the water, and the overall time spent in flight. The four species spent a similar proportion of their foraging time in flight (56,65%). During the day they were mostly flying (77,85% of the daylight period) whereas at night they were mainly (61,71%) sitting on the water. The amount of time spent in flight during the daytime foraging period was related to the amount of time spent sitting on the water at night. Differences between species occurred in the duration of bouts in flight and on the water as well as in the frequency of landings and in the time elapsed between successive landings. Yellow-nosed Albatrosses were more active than the other species, with more frequent short bouts in flight and more frequent successive landings at short intervals. Sooty Albatrosses landed or took-off less often than the other species and were more active just before dusk. Black-browed and Grey-headed Albatrosses were more active at night, especially the first part of the night and far from the colonies. Their trips consisted of a commuting part and a foraging part. Black-browed Albatrosses landed more often during the foraging than the commuting part, suggesting that they were not searching when travelling. The study suggests that there is no fundamental difference between the overall activity budgets of the four species although they show distinctive diet, morphology and life history traits. The differences observed between the four species were related mainly to differences in foraging technique. Comparison with the Wandering Albatross, the only species for which data were available previously, suggest that this larger species might differ completely in foraging technique from the smaller albatrosses. [source] Differential modulation of CD8, by rat ,, and ,, T cells after activationIMMUNOLOGY, Issue 3 2001Frank Straube Summary Major histocompatibility complex (MHC) class I-restricted ,, T cells express the CD8,, heterodimer, which acts as a MHC class I-specific co-receptor. Rats are so far the only species with frequent expression of the CD8,, by MHC-unrestricted ,, T cells. This study compares CD8,, expression by splenic rat ,, and ,, T cells and reveals a lineage-specific difference in the control of CD8, expression. After activation in vitro, many ,, T cells, but not ,, T cells, persistently down-modulate the expression of CD8,, but not CD8,, at the RNA level. Down-regulation occurred after stimulation with T-cell receptor (TCR)-specific monoclonal antibody (mAb) and interleukin-2 (IL-2) or CD28-mediated costimulation, and after activation with phorbol 12-myristate 13-acetate (PMA) and ionomycin. Functional differences between modulating and non-modulating cells were not found with respect to interferon-, (IFN-,) production and cytolytic activity. The modulation could be indicative for a fundamental difference between ,, and ,, T cells and also limits the use of CD8, as a stable marker of ,, T-cell subsets. Possibly, CD8, modulation provides a mechanism to escape over-stimulation by (auto-)antigens by increasing the threshold of TCR-mediated activation in ,, T cells. [source] Phylogeography of cave pseudoscorpions in southern AustraliaJOURNAL OF BIOGEOGRAPHY, Issue 6 2007T. A. Moulds Abstract Aim, To investigate molecular phylogenetic divergence and historical biogeography of the cave-dwelling pseudoscorpion genus Protochelifer. Location, Caves and nearby epigean habitats in southern Australia were sampled from western Victoria, Naracoorte Caves, Flinders Ranges, Kangaroo Island, Nullarbor Plain and south-west Western Australia. Methods, Allozyme electrophoresis (57 individuals) and a 569-base-pair section of the mtDNA COI gene (22 individuals) were used to reconstruct phylogenetic relationships among four cave species and three epigean species from 13 locations. Results, Phylogenetic reconstruction using the allozyme and mtDNA sequence data revealed a similar topology, showing recent speciation of several Protochelifer populations in caves from Naracoorte to the Nullarbor Plain. Naracoorte Caves contained a single species, Protochelifer naracoortensis, found in four separate caves, while all other cave species appear to be restricted to single caves. Main conclusions, At a local scale, as indicated by the four Naracoorte caves, dispersal is thought to occur via micro- and mesocaverns, and possibly by phoresy using insect or bat vectors. With current data we are unable to determine if cavernicolous species of Protochelifer have arisen from a single cave colonization event followed by phoretic dispersal on bats to other caves, or multiple cave-invasion events from independent epigean ancestors. Genetic heterogeneity among Protochelifer populations from Nullarbor caves suggest that P. cavernarum, the only species presently recorded from this region, is likely to constitute a species complex requiring further study to fully resolve its relationships. [source] The relationship of total and per-gram rankings in competitive effect to the natural abundance of herbaceous perennialsJOURNAL OF ECOLOGY, Issue 1 2001Timothy G. Howard Summary 1,Using a field experiment and a garden experiment, I estimated the rankings in total and per-gram competitive effect of non-woody perennial old-field species. 2,Total competitive effects were defined as the relative reduction in growth of a target from no-neighbour to with-neighbour conditions. Per-gram competitive effects were defined as the per-unit relative reduction in target growth among increasing neighbour densities, and were determined from the shape of a nonlinear curve fit through a distribution of normalized target performance against neighbour mass. 3,In both experiments, mean total competitive effect differed significantly among species, indicating a strong competitive hierarchy. In the garden experiment only species at opposite ends of the ranking differed significantly in per-gram competitive effect, resulting in a weaker competitive hierarchy based on this measure. 4,Nonetheless, rankings of per-gram competitive effect were more strongly correlated with rank in abundance than were rankings of total competitive effect. 5,Per-gram competitive effect may be more predictive of natural abundance than total competitive effect for at least two reasons. The effects of neighbour abundance on targets are nonlinear, and unlike total effects, per-gram estimates of competitive effect may therefore indicate how competition changes over time with changing neighbour densities. Also, if higher per-gram competitive effect reflects higher per-unit nutrient uptake rates, it would probably be advantageous to a species throughout the individual's life span, rather than only when the individual is larger than its surrounding neighbours. [source] Case studies in novel narial anatomy: 2.JOURNAL OF ZOOLOGY, Issue 4 2004The enigmatic nose of moose (Artiodactyla: Cervidae: Alces alces) Abstract The facial region of moose Alces alces is highly divergent relative to other cervids and other ruminants. In particular, the narial region forms an expanded muzzle or proboscis that overhangs the mouth. The nose of moose provides a case study in the evolution of narial novelty within a phylogenetically well-resolved group (Cervidae). The function of the nasal apparatus of moose remains enigmatic, and new hypotheses are proposed based on our anatomical findings. Head specimens of moose and outgroup taxa were subjected to medical imaging (CT scanning), vascular injection, gross anatomical dissection, gross sectioning, and skeletonization. Moose noses are characterized by highly enlarged nostrils accompanied by specialized musculature, expanded nasal cartilages, and an increase in the connective-tissue pad serving as the termination of the alar fold. The nostrils are widely separated, and the rhinarium that encircles both nostrils in outgroups is reduced to a tiny central patch in moose. The dorsal lateral nasal cartilage is modified to form a pulley mechanism associated with the levator muscle of the upper lip. The lateral accessory nasal cartilage is enlarged and serves as an attachment site for musculature controlling the aperture of the nostril, particularly the lateralis nasi, the apical dilatators, and the rectus nasi. Bony support for narial structures is reduced. Moose show greatly enlarged nasal cartilages, and the entire osseocartilaginous apparatus is relatively much larger than in outgroups. The nasal vestibule of moose is very large and houses a system of three recesses: one rostral and one caudal to the nostrils, and one associated with the enlarged fibrofatty alar fold. As a result of the expanded nasal vestibule, osseous support for the nasal conchae (i.e. turbinates) has retracted caudally along with the bony nasal aperture. The nasoturbinate and its mucosal counterparts (dorsal nasal concha and rectal fold) are reduced. The upturned maxilloturbinate, however, is associated with an enlarged ventral nasal concha and alar fold. Moose are the only species of cervid with these particular characteristics, indicating that this anatomical configuration is indeed novel. Although functional hypotheses await testing, our anatomical findings and published behavioural observations suggest that the novel narial apparatus of moose probably has less to do with respiratory physiology than with functions pertaining specifically to the nostrils. The widely separated and laterally facing nostrils may enhance stereolfaction (i.e. extracting directional cues from gradients of odorant molecules in the environment), but other attributes of narial architecture (enlarged cartilages, specialized musculature, recesses, fibrofatty pads) suggest that this function may not have been the evolutionary driving force. Rather, these attributes suggest a mechanical function, namely, an elaborated nostril-closing system. [source] The NMR structure of [Xd(C2)]4 investigated by molecular dynamics simulationsMAGNETIC RESONANCE IN CHEMISTRY, Issue 1 2003Thérèse E. Malliavin Abstract The i-motif tetrameric structure is built up from two parallel duplexes intercalated in a head-to-tail orientation, and held together by hemiprotonated cytosine pairs. Two topologies exist for the i-motif structure, one with outermost 3, extremities and the other with outermost 5, extremities, called the 3,E and 5,E topology, respectively. Since the comparison of sugar and phosphate group interactions between the two topologies is independent of the length of the intercalation motif, the relative stability of the 3,E and 5,E topologies therefore should not depend on this length. Nevertheless, it has been shown that the 3,E topology of the [d(C2)]4 is much more stable than the 5,E topology, and that the former is the only species observed in solution. In order to understand the reason for this atypical behavior, the NMR structure of the [Xd(C2)]4 was determined and analyzed by molecular dynamics simulations. In the NMR structure, the width of the narrow groove is slightly smaller than in previously determined i-motif structures, which supports the importance of phosphodiester backbone interactions in the structure stability. The simulations show that the stacking of cytosines, essential for the i-motif stability, is produced by a similar and non-negative twisting of the phosphodiester backbones. The twisting is induced by an interaction between the backbones; the [Xd(C2)]4 in 5,E topology, exhibiting very limited interaction between the phosphodiester backbones, is thus unstable. Copyright © 2002 John Wiley & Sons, Ltd. [source] The adipokinetic hormones of Heteroptera: a comparative studyPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2010DALIBOR KODRÍK The adipokinetic hormones (AKHs) from 15 species of heteropteran Hemiptera (encompassing eight families, six superfamilies and three infraorders) have been isolated and structurally identified using liquid chromatography coupled with mass spectrometry. None of the structures are novel and all are octapeptides. These peptide sequence data are used, together with the previously available AKH sequence data on Heteroptera, to create a larger dataset for comparative analyses. This results, in total, in AKH sequences from 30 species (spanning 13 families), which are used in a matrix confronted with the current hypotheses on the phylogeny of Heteroptera. The expanded dataset shows that all heteropterans have octapeptide AKHs; three species have two AKHs, whereas the overwhelming majority have only one AKH. From a total of 11 different AKH peptides known from Heteroptera to date, three AKHs occur frequently: Panbo-red pigment-concentrating hormone (RPCH) (×10), Schgr-AKH-II (×6) and Anaim-AKH (×4). The heteropteran database also suggests that particular AKH variants are family-specific. The AKHs of Heteroptera: Pentatomomorpha (all terrestrial) are not present in Nepomorpha (aquatic) and Gerromorpha: Gerridae (semiaquatic); AKHs with a Val in position 2 are absent in the Pentatomomorpha (only AKHs with Leu2 are present), whereas Val2 predominates in the nonterrestrial species. An unexpected diversity of AKH sequences is found in Nepomorpha, Nepoidea, Nepidae and Nepinae, whereas Panbo-RPCH (which has been identified in all infraorders of decapod crustaceans) is present in all analysed species of Pentatomidae and also in the only species of Tessaratomidae investigated. The molecular evolution of Heteroptera with respect to other insect groups and to crustaceans is discussed [source] Identification of the alkaloids of Galipea officinalis by gas chromatography,mass spectrometryPHYTOCHEMICAL ANALYSIS, Issue 5 2001Ingrid Jacquemond-Collet Abstract Galipea officinalis Hancock, a Venezuelan shrubby tree which is acclaimed in folk medicine for its many healing properties, is the only species of the genus to contain tetrahydroquinoline alkaloids. A GC-MS method has been developed in order to analyse the essential oil, hexane and chloroform extracts of the trunk bark of this plant, without prior derivatisation of the alkaloidal components. A study of the MS fragmentation patterns of the components permitted the identification of five new minor quinoline alkaloids together with the known alkaloids. In addition, the method could also be used for the characterisation of alkaloids within the genus Galipea. Copyright © 2001 John Wiley & Sons, Ltd. [source] Waterlogging tolerance in the tribe Triticeae: the adventitious roots of Critesion marinum have a relatively high porosity and a barrier to radial oxygen lossPLANT CELL & ENVIRONMENT, Issue 6 2001M. P. Mcdonald Abstract Nine species from the tribe Triticeae , three crop, three pasture and three ,wild' wetland species , were evaluated for tolerance to growth in stagnant deoxygenated nutrient solution and also for traits that enhance longitudinal O2 movement within the roots. Critesion marinum (syn. Hordeum marinum) was the only species evaluated that had a strong barrier to radial O2 loss (ROL) in the basal regions of its adventitious roots. Barriers to ROL have previously been documented in roots of several wetland species, although not in any close relatives of dryland crop species. Moreover, the porosity in adventitious roots of C. marinum was relatively high: 14% and 25% in plants grown in aerated and stagnant solutions, respectively. The porosity of C. marinum roots in the aerated solution was 1·8,5·4-fold greater, and in the stagnant solution 1·2,2·8-fold greater, than in the eight other species when grown under the same conditions. These traits presumably contributed to C. marinum having a 1·4,3 times greater adventitious root length than the other species when grown in deoxygenated stagnant nutrient solution or in waterlogged soil. The length of the adventitious roots and ROL profiles of C. marinum grown in waterlogged soil were comparable to those of the extremely waterlogging-tolerant species Echinochloa crus-galli L. (P. Beauv.). The superior tolerance of C. marinum, as compared to Hordeum vulgare (the closest cultivated relative), was confirmed in pots of soil waterlogged for 21 d; H. vulgare suffered severe reductions in shoot and adventitious root dry mass (81% and 67%, respectively), whereas C. marinum shoot mass was only reduced by 38% and adventitious root mass was not affected. [source] Language out of Music: The Four Dimensions of Vocal LearningTHE AUSTRALIAN JOURNAL OF ANTHROPOLOGY, Issue 3 2008Nicholas Bannan A growing consensus drawing on research in a wide variety of disciplines has, over the last fifteen years or so, argued the need to revisit Darwin's conjecture of 1871 that language may be descended from an existing, musical medium of communication that developed from animal calls. This paper seeks to examine, in an extension of Hockett's analysis of the design features required for linguistic communication, the nature of the acoustic information produced and perceived in human vocalisation, and to consider the anatomical and neural mechanisms on which these depend. An attempt is made to sketch an evolutionary chronology for key prerequisites of human orality. Cross-species comparisons are employed to illuminate the role of four acoustic variables (pitch, duration, amplitude and timbre), viewing the potential for human vocal productivity from the perspective of animal communication. Although humans are the only species to combine entrainment to pulse with attunement to precisely-tracked pitches, we also depend both for musical interaction and the production and perception of vowel sounds on precise and conscious control of the property of timbre. Drawing on, amongst others, Scherer's analyses of emotionally triggered sounds in a variety of species, and Fernald's presentation of the similarities of infant cries and adult production of infant-directed speech in a variety of cultures and languages, a case is made for the instinctive components of human communication being more music-like than language-like. In conclusion, historical and comparative data are employed to outline the adaptive and exaptive sequence by which human vocal communication evolved. The roles of selective pressures that conform to different adaptive models are compared,natural selection, sexual selection, group selection,leading to the proposal that all of these must have played their part at different stages in the process in a ,mosaic' model consistent with the development of other human traits. [source] Chimpanzee seed dispersal quantity in a tropical montane forest of RwandaAMERICAN JOURNAL OF PRIMATOLOGY, Issue 11 2009Nicole D. Gross-Camp Abstract We describe chimpanzee seed dispersal in the tropical montane forest of Nyungwe National Park (NNP), Rwanda, for a total of three years from January 1998 through May 2000 and May 2006 through March 2007. Relatively few studies have examined chimpanzee seed dispersal in montane communities where there are generally fewer fruiting tree species than in lowland forests. Such studies may reveal new insights into chimpanzee seed dispersal behaviors and the role that they play in forest regeneration processes. Chimpanzees are large-bodied, highly frugivorous, and tend to deposit the seeds of both large- and small-seeded fruits they consume in a viable state. We found that chimpanzees dispersed a total of 37 fruiting species (20 families) in their feces, 35% of which were large-seeded trees (,0.5,cm). A single large-seeded tree, Syzygium guineense, was the only species to be dispersed in both wadges and feces. Based on phenological patterns of the top five large-seeded tree species found in chimpanzee feces, our results indicate that chimpanzees do not choose fruits based on their availability. There was, however, a positive relationship between the presence of Ekebergia capensis seeds in chimpanzee feces and S. guineense seeds in chimpanzee wadges and their respective fruit availabilities. Our data reveal that proportionately fewer chimpanzee fecal samples at NNP contained seeds than that reported in two other communities in the Albertine Rift including one at mid-elevation and one in montane forest. As in other chimpanzee communities, seeds of Ficus spp. were the most common genus in NNP chimpanzee feces. Our data do not support previous studies that describe Ficus spp. as a fallback food for chimpanzees and highlights an intriguing relationship between chimpanzees and the large-seeded tree species, S. guineense. Am. J. Primatol. 71:901,911, 2009. © 2009 Wiley-Liss, Inc. [source] Re-sequencing regions of the ovine Y chromosome in domestic and wild sheep reveals novel paternal haplotypesANIMAL GENETICS, Issue 1 2009J. R. S. Meadows Summary The male-specific region of the ovine Y chromosome (MSY) remains poorly characterized, yet sequence variants from this region have the potential to reveal the wild progenitor of domestic sheep or examples of domestic and wild paternal introgression. The 5, promoter region of the sex-determining gene SRY was re-sequenced using a subset of wild sheep including bighorn (Ovis canadensis), thinhorn (Ovis dalli spp.), urial (Ovis vignei), argali (Ovis ammon), mouflon (Ovis musimon) and domestic sheep (Ovis aries). Seven novel SNPs (oY2,oY8) were revealed; these were polymorphic between but not within species. Re-sequencing and fragment analysis was applied to the MSY microsatellite SRYM18. It contains a complex compound repeat structure and sequencing of three novel size fragments revealed that a pentanucleotide element remained fixed, whilst a dinucleotide element displayed variability within species. Comparison of the sequence between species revealed that urial and argali sheep grouped more closely to the mouflon and domestic breeds than the pachyceriforms (bighorn and thinhorn). SNP and microsatellite data were combined to define six previously undetected haplotypes. Analysis revealed the mouflon as the only species to share a haplotype with domestic sheep, consistent with its status as a feral domesticate that has undergone male-mediated exchange with domestic animals. A comparison of the remaining wild species and domestic sheep revealed that O. aries is free from signatures of wild sheep introgression. [source] Thermal shock and germination in North-West European Genisteae: implications for heathland management and invasive weed control using fireAPPLIED VEGETATION SCIENCE, Issue 3 2009M.E. Hanley Abstract Question: Is the stimulation of germination by thermal shock (resulting from the passage of fire) commonly observed for Mediterranean-climate Fabaceae also apparent for NW European Genisteae (Fabaceae) species? Location: Southern England and NW France. Methods: The germination of Cytisus scopiarius, Genista anglica, Ulex europaeus, Ulex gallii and Ulex minor was examined following exposure to a range of temperatures (50°C, 65°C, 80°C, 95°C and 110°C) applied to seeds for 5 min. A sixth Mediterranean-origin species (Spartium junceum) was also included since it is a common invasive in NW Europe and North America. Results: All five native NW European species displayed increased germination following thermal shock, even when seeds were heated to 110°C. However, there was some variation depending on provenance: in contrast to seeds collected from southern England, germination of French C. scopiarius seeds was unaffected by temperature. Spartium junceum germinated most at 95°C, but was the only species to show reduced germination when seeds were heated to 110°C. Conclusions: The NW European Genisteae appear to be pre-adapted to the high temperatures associated with fire; a response attributable to their evolutionary origins in the fire-prone ecosystems of the Mediterranean Basin. Consequently, projected increases in fire frequency linked to climate change may stimulate their regeneration in NW European heathlands, potentially altering the species composition of these ecosystems. Additionally, a clearer understanding of the interaction between thermal shock and germination may explain why fire has so frequently been ineffective in controlling invasive Genisteae populations worldwide. [source] Effects on vegetation composition of a modified forest harvesting and propagation method compared with clear-cutting, scarification and plantingAPPLIED VEGETATION SCIENCE, Issue 2 2008Johan Bergstedt Question: How does the vegetation of boreal forests respond to harvesting and scarification? Location: 650 m a.s.l., central Sweden (61°38' N). Methods: The response of boreal forest vegetation to cutting and scarification was studied in a field trial, which consisted of three treatments plus conventional harvesting as a control in a complete block design with four replicates. The cutting was done 14 years prior to vegetation inventory and scarification and planting were conducted the first or second years after cutting. Results: The species most abundant at higher cutting intensities were crustose lichens, Cladonia spp., Cladina arbuscula, Polytrichum spp. and pioneer mosses, the grass Deschampsia flexuosa, and the tree Betula pubescens, A few species had substantially lower abundance in treatments with higher cutting intensity, notably Hylocomium splendens and Vaccinium myrtillus. Scarification had a strong effect that was different from the one created by cutting. In scarification treatments, Polytrichum spp. were the only species with high abundance; most species had low abundance, i.e. Barbilophozia lycopodioides, Vaccinium vitis-idaea, Pleurozium schreberi, Carex globularis, Empetrum nigrum, Cladina arbuscula, Sphagnum spp. Conclusions: Our results elaborate on the details of the well-known effect of cutting on ground-layer flora, and also give support for the profound and long-lasting effect that soil scarification has on forest vegetation. [source] Comparison of susceptibility of various fish species to experimental infection with channel catfish virusAQUACULTURE RESEARCH, Issue 16 2009Wan-An Yuan Abstract Channel catfish virus (CCV) disease is an acute haemorrhagic disease in juvenile channel catfish (Ictalurus punctatus). To date channel catfish is the only species affected by natural outbreaks of the CCV but juvenile large mouth bass (Micropterus salmoides) and silurus (Silurus meriaionalis) have suffered high mortalities in recent years in China. Histopathological phenomenon of sick fish is similar to CCV disease, and the identified virus was CCV. In this report, the pathogenicity of infectious CCV was examined by infection trials on the first known host species, the channel catfish and other teleosts. Our results indicated that there were higher detection rates of CCV from large mouth bass and silurus fish. Channel catfish virus did not induce mortality in other cypriniformes, but histopathological studies revealed that carp might be infected by both bathing and intraperitoneal infection. No deaths, clinical or histopathological signs, were found in the six other species exposed by immersion or injection. Experimental infection studies confirm that CCV infect not only channel catfish but also other species (large mouth bass, silutus and carp). The outbreaks of CCV disease only occurred when the cultured temperature was above 25 °C. [source] The potential of seed-eating birds to spread viable seeds of weeds and other undesirable plantsAUSTRAL ECOLOGY, Issue 7 2009LAURIE E. TWIGG Abstract The potential for seed-eating birds to spread viable seeds was investigated using captive-feeding trials to determine seed preference, passage time through the gut, and viability of passed seeds for bronzewing pigeons (Phaps chalcoptera), peaceful doves (Geopelia striata), crested pigeons (Ocyphaps lophotes), Senegal doves (Streptopelia senegalensis), zebra finches (Taeniopygia guttata), black ducks (Anas superciliosa) and wood ducks (Chenonetta jubata). Test seeds were bladder clover (Trifolium spumosum), crimson clover (Trifolium incarnatum), gorse (Ulex europaeus), canola (Brassica napus) and red panicum (Setaria italica). Their consumption was compared with that of commercial seed mixes. Although all test seeds were recognizable foods, their consumption usually decreased in the presence of other foods, except for canola, where consumption rates were maintained. Hard-seeded bladder clover was the only species where viable seeds were passed by obligate seedeaters. In contrast, viable seeds of canola and gorse were passed by seed-eating omnivorous/herbivorous ducks, although the germination of passed seeds (42%) was reduced significantly compared with that of untreated control seed (67%). Field validation with wild, urban bronzewings and Australian magpies (Gymnorhina tibicen) offered canola and commercial seed yielded similar outcomes, with a range of viable seeds recovered from magpie soft pellets. Mean seed passage time in captive birds ranged from 0.5 to 4.3 h for all test seeds and commercial seed mixes, suggesting that these bird species may potentially disperse seed over moderate distances. Despite the low probability of individual birds spreading viable seed, the high number of birds feeding in the wild suggests that the potential for granivorous and seed-eating omnivorous birds to disperse viable seeds cannot be discounted, particularly if exozoochorous dispersal is also considered. [source] Bahiaxenidae, a "living fossil" and a new family of Strepsiptera (Hexapoda) discovered in BrazilCLADISTICS, Issue 6 2009Freddy Bravo An adult male of a newly discovered strepsipteran species from Brazil,Bahiaxenos relictus,is described. A new family Bahiaxenidae is suggested based on cladistic analyses of comprehensive morphological data sets with a broad taxon sampling including the stem group. It is unambiguously placed as the sister group of all other extant families of Strepsiptera. Bahiaxenos relictus is the only species of basal, i.e. non-stylopidian, Strepsiptera occurring in the New World. It appears to be a relict taxon that has survived in the fossil sand dunes of the São Francisco River (Bahia State). The loss of the 8th antennomere and the greatly reduced labrum are autapomorphies of Strepsiptera s.s. excluding Bahiaxenidae. The sister group relationship between,Protoxenidae and the remaining Strepsiptera, and between ,Cretostylops and a clade comprising ,Mengea and Strepsiptera s.s., is confirmed, as is the monophyly of Stylopidia and Stylopiformia. [source] | |||||||||||||||||||