Search results for " America."
showing 10 items of 686 documents
The influence of space and time on the evolution of altruistic defence: the case of ant slave rebellion.
2016
How can antiparasite defence traits evolve even if they do not directly benefit their carriers? An example of such an indirect defence is rebellion of enslaved Temnothorax longispinosus ant workers against their social parasite Temnothorax americanus, a slavemaking ant. Ant slaves have been observed to kill their oppressors' offspring, a behaviour from which the sterile slaves cannot profit directly. Parasite brood killing could, however, reduce raiding pressure on related host colonies nearby. We analyse with extensive computer simulations for the Temnothorax slavemaker system under what conditions a hypothetical rebel allele could invade a host population, and in particular, how host-para…
Contrasting biogeographical patterns in Margarella (Gastropoda: Calliostomatidae: Margarellinae) across the Antarctic Polar Front
2021
International audience; Members of the trochoidean genus Margarella (Calliostomatidae) are broadly distributed across Antarctic and sub-Antarctic ecosystems. Here we used novel mitochondrial and nuclear gene sequences to clarify species boundaries and phylogenetic relationships among seven nominal species distributed on either side of the Antarctic Polar Front (APF). Molecular reconstructions and species-delimitation analyses recognized only four species: M. antarctica (the Antarctic Peninsula), M. achilles (endemic to South Georgia), M. steineni (South Georgia and Crozet Island) and the morphologically variable M. violacea (=M. expansa, M. porcellana and M. pruinosa), with populations in s…
Phylogeography and Molecular Evolution of Potato virus Y
2012
Potato virus Y (PVY) is an important plant pathogen, whose host range includes economically important crops such as potato, tobacco, tomato, and pepper. PVY presents three main strains (PVYO, PVYN and PVYC) and several recombinant forms. PVY has a worldwide distribution, yet the mechanisms that promote and maintain its population structure and genetic diversity are still unclear. In this study, we used a pool of 77 complete PVY genomes from isolates collected worldwide. After removing the effect of recombination in our data set, we used Bayesian techniques to study the influence of geography and host species in both PVY population structure and dynamics. We have also performed selection and…
Study of a New Population of the Argentinian Endemic Species Riella choconensis Hässel (Riellaceae, Marchantiophyta) Reveals a Novel Anatomical Struc…
2019
A new population of the Argentinian endemic Riella choconensis Hässel (Riellaceae, Marchantiophyta) was discovered from a culture of sediments from the Laguna de los Juncos (Río Negro province, Argentina). This species was known previously from two nearby collections, made in 1984, in the type locality at the Ramos Mexía reservoir (Neuquén province) and was not recorded since. Fresh material from the new population enabled detailed morphological analyses, which are extensively described here, illustrated and compared to type material of the species. Based on the smooth female involucre, the species belongs to subgenus Riella Mont. However, cross-sections of this structure showed that R. cho…
An annotated checklist of freshwater Copepoda (Crustacea, Hexanauplia) from continental Ecuador and the Galapagos Archipelago.
2019
An annotated checklist of the free-living freshwater Copepoda recorded in different regions in Ecuador (including the Amazon, the Andes, the coastal region, and the Galapagos Islands) is here provided. We revised all published records, critically evaluated the validity of each taxon and provided short taxonomic and biogeographical remarks for each one. A total of 27 taxa have been reported, including species and records at the generic level only. The species and taxa identified only up to the generic level belong to five families and 14 genera. The Cyclopoida is the most diverse group with 16 records belonging to species (or identified to the generic level only) and eight genera, followed b…
Castniidae of the Museum of Natural History of the University of Wrocław: new findings from Friedrich Wilhelm Niepelt's collection with comments on K…
2021
Further results of our research into the Giant Butterfly-Moths (Castniidae) of the Museum of Natural History (University of Wrocław) are presented. Castniids of the Niepelt collection had previously been reviewed. However, while curating other sections of the Lepidoptera collection, we discovered 18 misplaced specimens belonging to nine taxa of Castniidae, several of them bearing typical labels by Niepelt. Among them, two are of particular interest, insofar as they are associated with the world-class botanists August Weberbauer (1871–1948) and Karl Adolf Georg Lauterbach (1864–1937).
Late Cretaceous-Early Eocene origin of yams (Dioscorea, Dioscoreaceae) in the Laurasian Palaearctic and their subsequent Oligocene-Miocene diversific…
2015
Aim: Dioscorea (Dioscoreaceae) is a predominantly pantropical genus (< 600 species) that includes the third most important tropical tuber crop and species of pharmacological value. Fossil records from both the Northern and Southern Hemispheres were used to test hypotheses about the origin of the genus Dioscorea, and to examine potential macroevolutionary processes that led to its current distribution. Location: Pantropical distribution. Methods: Divergence times were estimated using the most comprehensive phylogeny of the group published to date based on plastid sequences and fossil calibrations, applying a relaxed-clock model approach. Ancestral areas and range shifts were reconstructed us…
Hydrology Affects Environmental and Spatial Structuring of Microalgal Metacommunities in Tropical Pacific Coast Wetlands
2016
The alternating climate between wet and dry periods has important effects on the hydrology and therefore on niche-based processes of water bodies in tropical areas. Additionally, assemblages of microorganism can show spatial patterns, in the form of a distance decay relationship due to their size or life form. We aimed to test spatial and environmental effects, modulated by a seasonal flooding climatic pattern, on the distribution of microalgae in 30 wetlands of a tropical dry forest region: the Pacific coast of Costa Rica and Nicaragua. Three surveys were conducted corresponding to the beginning, the highest peak, and the end of the hydrological year during the wet season, and species abun…
Two new species of Brusqeulia Razowski & Becker, 2000 from the Neotropics, with comments on the systematic position of the genus in relation to the A…
2018
Two new species of the neotropical genus Brusqeulia Razowski &amp; Becker, 2000, are described and illustrated: B.yunkensis Pérez Santa-Rita &amp; Baixeras, sp. n. from Bolivia and B.araguensis Pérez Sant-Rita &amp; Baixeras, sp. n. from Venezuela. The systematic position and diagnostic characters of the genus are reviewed, resulting in the synonymy of Pinhaisania Razowski &amp; Becker, 2000, with Brusqeulia, and the combination B.crispula (Razowski &amp; Becker, 2000), comb. n. New characters of the female genitalia are discussed.
Comparative analyses of caste, sex, and developmental stage‐specific transcriptomes in two Temnothorax ants
2020
Abstract Social insects dominate arthropod communities worldwide due to cooperation and division of labor in their societies. This, however, makes them vulnerable to exploitation by social parasites, such as slave‐making ants. Slave‐making ant workers pillage brood from neighboring nests of related host ant species. After emergence, host workers take over all nonreproductive colony tasks, whereas slavemakers have lost the ability to care for themselves and their offspring. Here, we compared transcriptomes of different developmental stages (larvae, pupae, and adults), castes (queens and workers), and sexes of two related ant species, the slavemaker Temnothorax americanus and its host Temnoth…