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| | 1. |
2007 Apr 3 |
Homogenous rivers, homogenous faunas
Moyle, Mount
Proc Natl Acad Sci U S A 2007 Apr 3;104(14):5711-5712.
[Pubmed: 17392424]
| | 2. |
2003 Nov 22 |
Antimicrobial egg cleaning by the fringed darter (Perciformes: Percidae: Etheostoma crossopterum): implications of a novel component of parental care in fishes.
Knouft JH, Page LM, Plewa MJ
Proc. Biol. Sci. 2003 Nov 22;270(1531):2405-11.
Abstract
Broad-spectrum antimicrobial compounds have recently been identified in the epidermal mucus of fishes and probably serve as a first line of defence against microbial pathogens. Because of the ubiquitous nature of fungi and bacteria in aquatic systems, defence against these pathogens should be required throughout the lifespan of fishes, including the egg stage. We conducted experiments on Etheostoma crossopterum (Percidae: Catonotus), the fringed darter, to determine if the presence of a guarding male inhibits microbial colonization of eggs. Based on results from a combination of in-stream experiments, in vitro microbial assays, and morphological characteristics and behaviour of breeding males, we propose that antimicrobial egg cleaning by the guarding male is an effective component of parental care in these fish. Although innate antimicrobial compounds have been identified in a variety of organisms ranging from insects to vertebrates, integration of these compounds into a species's reproductive life history has been identified only in a small number of insect species. The results from this study not only indicate that E. crossopterum males provide a novel form of vertebrate parental care, but also have implications regarding the evolution of parental care in fishes and transitional evolutionary stages from no parental care to male parental care.
[Pubmed: 14667358]
| | 3. |
2006 Nov 15 |
Spatiotemporal variability of stream habitat and movement of three species of fish.
Roberts JH, Angermeier PL
Oecologia. 2007 Mar;151(3):417-30. Epub 2006 Nov 15.
Abstract
Relationships between environmental variability and movement are poorly understood, due to both their complexity and the limited ecological scope of most movement studies. We studied movements of fantail (Etheostoma flabellare), riverweed (E. podostemone), and Roanoke darters (Percina roanoka) through two stream systems during two summers. We then related movement to variability in measured habitat attributes using logistic regression and exploratory data plots. We indexed habitat conditions at both microhabitat (i.e., patches of uniform depth, velocity, and substrate) and mesohabitat (i.e., riffle and pool channel units) spatial scales, and determined how local habitat conditions were affected by landscape spatial (i.e., longitudinal position, land use) and temporal contexts. Most spatial variability in habitat conditions and fish movement was unexplained by a site's location on the landscape. Exceptions were microhabitat diversity, which was greater in the less-disturbed watershed, and riffle isolation and predator density in pools, which were greater at more-downstream sites. Habitat conditions and movement also exhibited only minor temporal variability, but the relative influences of habitat attributes on movement were quite variable over time. During the first year, movements of fantail and riverweed darters were triggered predominantly by loss of shallow microhabitats; whereas, during the second year, microhabitat diversity was more strongly related (though in opposite directions) to movement of these two species. Roanoke darters did not move in response to microhabitat-scale variables, presumably because of the species' preference for deeper microhabitats that changed little over time. Conversely, movement of all species appeared to be constrained by riffle isolation and predator density in pools, two mesohabitat-scale attributes. Relationships between environmental variability and movement depended on both the spatiotemporal scale of consideration and the ecology of the species. Future studies that integrate across scales, taxa, and life-histories are likely to provide greater insight into movement ecology than will traditional, single-season, single-species approaches.
[Pubmed: 17106722]
| | 4. |
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Parasitic fauna of eight species of ornamental freshwater fish species from the middle Negro River in the Brazilian Amazon Region.
Tavares-Dias M, Lemos JR, Martins ML
Rev Bras Parasitol Vet.;19(2):103-7.
Abstract
Twenty-seven specimens of cardinal tetra Paracheirodon axelrodi, 33 rosy tetra Hyphessobrycon copelandi (Characidae), 28 marbled hatchetfish Carnegiella strigata, 26 blackwing hatchetfish Carnegiella martae (Gasteropelecidae), 27 bodó Ancistrus hoplogenys (Loricariidae), 31 brown pencilfish Nannostomus eques, 38 oneline pencilfish Nannostomus unifasciatus (Lebiasinidae) and 13 angelfish Pterophyllum scalare (Cichlidae) were collected from the middle Negro River, State of Amazonas, Brazil, for parasitological studies. Out of the total of 223 fish examined, 143 (64.1%) were parasitized by at least one parasite species. The highest prevalence rate was for Monogenea (36.7%), followed by Ichthyophthirius multifiliis (Ciliophora) (20.6%), Trichodina spp. (Ciliophora) (4.0%), Piscinoodinium pillulare (Dinoflagellida) (1.3%), Tetrahymena sp. (Ciliophora) (0.89%), and Procamallanus sp. (Nematoda) (0.4%). All eight fish species had Monogenea (Gyrodactylidae and Dactylogyridae) in the gills, but the highest prevalence occurred in P. scalare and the lowest in P. axelrodi and C. strigata. However, the highest mean intensity of Monogenea was found in P. scalare and A. hoplogenys. The protozoan I. multifiliis occurred in the six ornamental fish species examined, but C. strigata and C. martae had higher prevalence and mean intensity. Trichodina spp. were found only in the gills of C. strigata, C. martae and N. eques, and with higher mean intensity in C. strigata. On the other hand, the protozoan P. pilullare was found only in the gills of C. martae. This is the first report of Tetrahymena sp. in Brazil, and it occurred in the gills of C. strigata.
[Pubmed: 20624347]
| | 5. |
2010 Oct 14 |
Phylogenetic Analysis of Pelecaniformes (Aves) Based on Osteological Data: Implications for Waterbird Phylogeny and Fossil Calibration Studies
Smith
PLoS One 2010 Oct 14;5(10). published online before print
Abstract
Debate regarding the monophyly and relationships of the avian order Pelecaniformes represents a classic example of discord between morphological and molecular estimates of phylogeny. This lack of consensus hampers interpretation of the group's fossil record, which has major implications for understanding patterns of character evolution (e.g., the evolution of wing-propelled diving) and temporal diversification (e.g., the origins of modern families). Relationships of the Pelecaniformes were inferred through parsimony analyses of an osteological dataset encompassing 59 taxa and 464 characters. The relationships of the Plotopteridae, an extinct family of wing-propelled divers, and several other fossil pelecaniforms (Limnofregata, Prophaethon, Lithoptila, ?Borvocarbo stoeffelensis) were also assessed. The antiquity of these taxa and their purported status as stem members of extant families makes them valuable for studies of higher-level avian diversification.
[Pubmed: 20976229]
| | 6. |
2010 Oct 18 |
Multiple mating and its relationship to alternative modes of gestation in male-pregnant versus female-pregnant fish species.
Avise JC, Liu JX
Proc. Natl. Acad. Sci. U.S.A. 2010 Nov 2;107(44):18915-20. Epub 2010 Oct 18.
Abstract
We construct a verbal and graphical theory (the "fecundity-limitation hypothesis") about how constraints on the brooding space for embryos probably truncate individual fecundity in male-pregnant and female-pregnant species in ways that should differentially influence selection pressures for multiple mating by males or by females. We then review the empirical literature on genetically deduced rates of multiple mating by the embryo-brooding parent in various fish species with three alternative categories of pregnancy: internal gestation by males, internal gestation by females, and external gestation (in nests) by males. Multiple mating by the brooding gender was common in all three forms of pregnancy. However, rates of multiple mating as well as mate numbers for the pregnant parent averaged higher in species with external as compared with internal male pregnancy, and also for dams in female-pregnant species versus sires in male-pregnant species. These outcomes are all consistent with the theory that different types of pregnancy have predictable consequences for a parent's brood space, its effective fecundity, its opportunities and rewards for producing half-sib clutches, and thereby its exposure to selection pressures for seeking multiple mates. Overall, we try to fit these fecundity-limitation phenomena into a broader conceptual framework for mating-system evolution that also includes anisogamy, sexual-selection gradients, parental investment, and other selective factors that can influence the relative proclivities of males versus females to seek multiple sexual partners.
[Pubmed: 20956296]
| | 7. |
2011 Aug 18 |
FLUCTUATIONS IN DENSITIES OF THE INVASIVE GILL PARASITE CENTROCESTUS FORMOSANUS (TREMATODA: HETEROPHYIDAE) IN THE COMAL RIVER, COMAL COUNTY, TEXAS, U.S.A.
Johnson M, Bolick A, Alexander M, Huffman D, Oborney E, Monroe A
J Parasitol. 2011 Aug 18; [Epub ahead of print]
Abstract
Abstract Centrocestus formosanus (Trematoda: Heterophyidae) is an invasive fish parasite in the Comal River, Texas, and is considered a threat to the federally endangered fountain darter, Etheostoma fonticola. Monitoring densities of C. formosanus cercariae is crucial to determining levels of infection pressure. We sampled 3 sites in the Comal River during 2 sampling periods, the first during 2006 - 2007, and again during 2009 - 2010. Two of the sites were located in the upstream reach of Landa Lake, sites HS and LA, and the third site was located downstream of Landa Lake in the old channel of the river. Cercariae densities were highest at the downstream most site (EA), followed by sites LA and HS, during both sampling periods, but a significant decline in cercariae density was observed between the first and second sampling periods. Several abiotic factors were monitored, including total stream discharge, wading discharge, temperature, and dissolved oxygen, but no river-wide trends were observed. Therefore, we speculate that these factors do not adequately explain the observed long-term decline in cercariae density. We propose that the decline is simply a reflection of a typical pattern followed by most invasive species as they gradually become integrated into the local community following an initial explosive growth in population size. Although cercariae densities may be abating, fountain darters in the Comal River are still threatened by the parasite, and conservation efforts must focus on reducing levels of infection pressure from the parasite whenever possible.
[Pubmed: 21851264]
| | 8. |
2011 Oct |
Spatial patterns of mercury in macroinvertebrates and fishes from streams of two contrasting forested landscapes in the eastern United States
Riva-Murray, Chasar, Bradley, Burns, Brigham, Smith, Abrahamsen
Ecotoxicology 2011 Oct;20(7):1530-1542.
Abstract
Controls on mercury bioaccumulation in lotic ecosystems are not well understood. During 2007–2009, we studied mercury and stable isotope spatial patterns of macroinvertebrates and fishes from two medium-sized (<80 km2) forested basins in contrasting settings. Samples were collected seasonally from multiple sites across the Fishing Brook basin (FBNY), in New York’s Adirondack Mountains, and the McTier Creek basin (MCSC), in South Carolina’s Coastal Plain. Mean methylmercury (MeHg) concentrations within macroinvertebrate feeding groups, and mean total mercury (THg) concentrations within most fish feeding groups were similar between the two regions. However, mean THg concentrations in game fish and forage fish, overall, were much lower in FBNY (1300 and 590 ng/g dw, respectively) than in MCSC (2300 and 780 ng/g dw, respectively), due to lower trophic positions of these groups from FBNY (means 3.3 and 2.7, respectively) than MCSC (means 3.7 and 3.3, respectively). Much larger spatial variation in topography and water chemistry across FBNY contributed to greater spatial variation in biotic Hg and positive correlations with dissolved MeHg and organic carbon in streamwater. Hydrologic transport distance (HTD) was negatively correlated with biotic Hg across FBNY, and was a better predictor than wetland density. The small range of landscape conditions across MCSC resulted in no consistent spatial patterns, and no discernable correspondence with local-scale environmental factors. This study demonstrates the importance of local-scale environmental factors to mercury bioaccumulation in topographically heterogeneous landscapes, and provides evidence that food-chain length can be an important predictor of broad-scale differences in Hg bioaccumulation among streams.
[Pubmed: 21743999]
| | 9. |
2012 Jan 9 |
A new species and first record of the genus
Triacanthella Schäffer, 1897 (Collembola, Poduromorpha, Hypogastruridae) for Africa
Janion, D'Haese, Deharveng
Zookeys 2012 Jan 9;(163):57-68. published online before print
Abstract
The first species of the genus Triacanthella to be recorded from Africa is described. Triacanthella madiba sp. n. belongs to the Southern Hemisphere group of the genus. It is morphologically closely related to Triacanthella vogeli Weiner & Najt, 1997 from Chile, and appears to be a gondwanian relict. The new species is also the first Triacanthella recorded from a guano habitat.
[Pubmed: 22303129]
| | 10. |
2012 Jul 5 |
Social complexity as a proximate and ultimate factor in communicative complexity
Freeberg, Dunbar, Ord
Philos Trans R Soc Lond B Biol Sci 2012 Jul 5;367(1597):1785-1801.
Abstract
The ‘social complexity hypothesis’ for communication posits that groups with complex social systems require more complex communicative systems to regulate interactions and relations among group members. Complex social systems, compared with simple social systems, are those in which individuals frequently interact in many different contexts with many different individuals, and often repeatedly interact with many of the same individuals in networks over time. Complex communicative systems, compared with simple communicative systems, are those that contain a large number of structurally and functionally distinct elements or possess a high amount of bits of information. Here, we describe some of the historical arguments that led to the social complexity hypothesis, and review evidence in support of the hypothesis. We discuss social complexity as a driver of communication and possible causal factor in human language origins. Finally, we discuss some of the key current limitations to the social complexity hypothesis—the lack of tests against alternative hypotheses for communicative complexity and evidence corroborating the hypothesis from modalities other than the vocal signalling channel.
[Pubmed: 22641818]
| | 11. |
2012 Jun 15 |
Revision of the Afrotropical Oberthuerellinae (Cynipoidea, Liopteridae)
Buffington, van Noort
Zookeys 2012 Jun 15;(202):1-154. published online before print
Abstract
The Afrotropical Oberthuerellinae are revised, and new dichotomous and multi-entry keys to the species of Oberthuerella, Tessmannella, and Xenocynips are provided. All previously described species in these genera are redescribed; descriptions are augmented by color images of the holotype for each species. The following 11 species are described as new: Oberthuerella cyclopia Buffington & van Noort; Oberthuerella eschara Buffington & van Noort; Oberthuerella kibalensis van Noort & Buffington; Oberthuerella pardolatus Buffington & van Noort; Oberthuerella sharkeyi Buffington & van Noort; Oberthuerella simba Buffington & van Noort; Tessmannella copelandi Buffington & van Noort; Tessmannella kiplingi Buffington & van Noort; Tessmannella roberti Buffington & van Noort; Xenocynips rhothion Buffington & van Noort; and Xenocynips ronquisti Buffington & van Noort. We provide identification keys to the genera and species occurring in the Afrotropical region. Online dichotomous and interactive Lucid keys to genera and species are available at http://www.waspweb.org/Cynipoidea/Keys/index.htm
[Pubmed: 22773909]
| | 12. |
2012 Jun |
Phylogeography of the prehensile-tailed skink Corucia zebrata on the Solomon Archipelago
Hagen, Donnellan, Bull
Ecol Evol 2012 Jun;2(6):1220-1234.
Abstract
The biogeography of islands is often strongly influenced by prior geological events. Corucia zebrata (Squamata: Scincidae) is endemic to the geologically complex Solomon Archipelago in Northern Melanesia. We examined the level of divergence for different island populations of C. zebrata and discussed these patterns in light of Pleistocene land bridges, island isolation, and island age. Corucia zebrata was sampled from 14 locations across the Solomon Archipelago and sequenced at two mitochondrial genes (ND2 and ND4; 1697 bp in total) and four nuclear loci (rhodopsin, an unknown intron, AKAP9, and PTPN12). Measures of genetic divergence, analyses of genetic variation, and Bayesian phylogenetic inference were used and the data assessed in light of geological information. Populations of C. zebrata on separate islands were found to be genetically different from each other, with reciprocal monophyly on mitochondrial DNA. Populations on islands previously connected by Pleistocene land bridges were marginally less divergent from each other than from populations on other nearby but isolated islands. There are indications that C. zebrata has radiated across the eastern islands of the archipelago within the last 1–4 million years. Nuclear loci were not sufficiently informative to yield further information about the phylogeography of C. zebrata on the Solomon Archipelago. Analyses of the mitochondrial data suggest that dispersal between islands has been very limited and that there are barriers to gene flow within the major islands. Islands that have been isolated during the Pleistocene glacial cycles are somewhat divergent in their mitochondrial genotypes, however, isolation by distance (IBD) and recent colonization of isolated but geologically younger islands appear to have had stronger effects on the phylogeography of C. zebrata than the Pleistocene glacial cycles. This contrasts with patterns reported for avian taxa, and highlights the fact that biogeographic regions for island species cannot be directly extrapolated among taxa of differing dispersal ability.
[Pubmed: 22833796]
| | 13. |
1991 Mar 1 |
Multilayering and loss of apical polarity in MDCK cells transformed with viral K-ras
J Cell Biol 1991 Mar 1;112(5):873-889.
Abstract
The effects of viral Kirsten ras oncogene expression on the polarized phenotype of MDCK cells were investigated. Stable transformed MDCK cell lines expressing the v-K-ras oncogene were generated via infection with a helper-independent retroviral vector construct. When grown on plastic substrata, transformed cells formed continuous monolayers with epithelial-like morphology. However, on permeable filter supports where normal cells form highly polarized monolayers, transformed MDCK cells detached from the substratum and developed multilayers. Morphological analysis of the multilayers revealed that oncogene expression perturbed the polarized organization of MDCK cells such that the transformed cells lacked an apical--basal axis around which the cytoplasm is normally organized. Evidence for selective disruption of apical membrane polarity was provided by immunolocalization of membrane proteins; a normally apical 114-kD protein was randomly distributed on the cell surface in the transformed cell line, whereas normally basolateral proteins remained exclusively localized to areas of cell contact and did not appear on the free cell surface. The discrete distribution of the tight junction-associated ZO-1 protein as well as transepithelial resistance and flux measurements suggested that tight junctions were also assembled. These findings indicate that v-K-ras transformation alters cell-substratum and cell-cell interactions in MDCK cells. Furthermore, v-K-ras expression perturbs apical polarization but does not interfere with the development of a basolateral domain, suggesting that apical and basolateral polarity in epithelial cells may be regulated independently.
[Pubmed: 1999461]
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