RESUMO
Afrotropical Acraeini butterflies provide a fascinating potential model system to contrast with the Neotropical Heliconiini, yet their phylogeny remains largely unexplored by molecular methods and their generic level nomenclature is still contentious. To test the potential of mitogenomes in a simultaneous analysis of the radiation, we sequenced the full mitochondrial genomes of 19 African species. Analyses show the potential of mitogenomic phylogeny reconstruction in this group. Inferred relationships are largely congruent with a previous multilocus study. We confirm a monophyletic Telchinia to include the Asiatic Pareba with a complicated paraphylum, traditional (sub)genus Acraea, toward the base. The results suggest that several proposed subgenera and some species groups within Telchinia are not monophyletic, while two other (sub)genera could possibly be combined. Telchinia was recovered without strong support as sister to the potentially interesting system of distasteful model butterflies known as Bematistes, a name that is suppressed in some treatments. Surprisingly, we find that this taxon has remarkably divergent mitogenomes and unexpected synapomorphic tRNA rearrangements. These gene order changes, combined with evidence for deviating dN/dS ratios and evidence for episodal diversifying selection, suggest that the ancestral Bematistes mitogenome has had a turbulent past. Our study adds genetic support for treating this clade as a distinct genus, while the alternative option, adopted by some authors, of Acraea being equivalent to Acraeini merely promotes redundancy. We pave the way for more detailed mitogenomic and multi-locus molecular analyses which can determine how many genera are needed (possibly at least six) to divide Acraeini into monophyletic groups that also facilitate communication about their biology.
Assuntos
Borboletas/genética , Genoma Mitocondrial/genética , Genômica , Filogenia , Animais , Borboletas/classificação , Ordem dos Genes/genética , RNA de Transferência/genéticaRESUMO
1 The acute effect of orally administered propranolol (100 mg/kg) on blood pressure, heart rate, cardiac output, venous pressure, haemoglobin concentration and oxygen uptake was studied in conscious rats. 2 Oxygen uptake was measured in a closed circuit respirometer and cardiac output determined by the direct Fick method. Other variables were measured by means of chronically implanted cannulae. 3 Significant falls occurred in heart rate (8.9%), cardiac output (30.5%), derived stroke volume (21.3%) and oxygen uptake (12.2%). 4 There were significant rises in arterial blood pressure (12.9%), derived arterial resistance (69%), arterio-venous oxygen difference (31.5%) and arterial haemoglobin concentration (6.3%). 5 A rise in venous pressure occurred in lightly anaesthetized rats but was only of borderline significance. 6 Correlations between the different variables revealed only one significant relationship, between heart rate and oxygen uptake. 7 It is concluded that only one primary site of action of propranolol has to be postulated to account for these findings, that of the well known negative inotropic and chronotropic effect on the heart.
Assuntos
Hemodinâmica/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Propranolol/farmacologia , Animais , Feminino , Pressorreceptores/efeitos dos fármacos , Ratos , Ratos Endogâmicos , Pressão Venosa/efeitos dos fármacosRESUMO
1 In a previous study in conscious rats, orally administered propranolol acutely lowered cardiac output by 30.5% and oxygen uptake by 12.2%, while oxygen extraction rose by 31.5%. The present study is concerned with the way in which the rat meets its oxygen requirements against such a fall in perfusion. 2 The effect of known concentrations of propranolol on haemoglobin-oxygen affinity was studied in vitro. The effect of orally administered propranolol (given acutely and chronically) was then determined and this was related to the concentration of the drug in plasma and red cells. Further studies were made on the action of propranolol on the Bohr effect and on arterial oxygen carriage. 3 In vitro, high concentrations of propranolol (1 x 10(-4) M) influenced haemoglobin-oxygen affinity in a biphasic manner and this was associated with changes in haematocrit and red cell and plasma pH. No change occurred in affinity after acute or chronic oral administration of the drug due to insufficient concentration in the blood. No direct action of the Bohr effect was detected. 4 Arterial oxygen content rose acutely due to an increase in haemoglobin concentration. 5 It is concluded that increased oxygen extraction in propranolol-treated rats is not explained by the actions of the drug on haemoglobin-oxygen affinity.
Assuntos
Oxigênio/sangue , Propranolol/farmacologia , Animais , Feminino , Hemoglobinas/análise , Hemoglobinas/metabolismo , Concentração de Íons de Hidrogênio , Propranolol/sangue , Ratos , Ratos EndogâmicosRESUMO
Higher taxa often show increasing species richness towards tropical low latitudes, a pattern known as the latitudinal biodiversity gradient (LBG). A rare reverse LBG (with greater richness towards temperate high latitudes) is exhibited by Gracillariidae leaf-mining moths, in which most described species occur in northern temperate areas. We carried out the first assessment of gracillariid species diversity in two Neotropical regions to test whether the relatively low tropical species diversity of this family is genuine or caused by insufficient sampling and a strong taxonomic impediment. Field surveys in six French Guianan and one Ecuadorian site produced 516 gracillariid specimens that were DNA barcoded to facilitate identification and to match larvae inside leaf mines with adults. Species delineation from sequence data was approximated using Automatic Barcode Gap Discovery and Refined Single Linkage Analysis through the Barcode Index Number system, and the proportion of described/undescribed species was estimated after comparison with types of 83% of described species. Locally, alpha-diversity far exceeds that of any known temperate fauna, with as many as 108 candidate species (59.3% as singletons) collected at one site, and with an estimated species richness lower bound of 240 species. Strikingly, at least 85% of the species collected as adults were found to be undescribed. Our sampling represents the most thorough survey of gracillariid species diversity in the Neotropics to date and the results from both our molecular and morphological analyses indicate that the current reverse LBG seen in this group is an artefact of insufficient sampling and a strong description deficit in the Neotropics.
Assuntos
Biodiversidade , Código de Barras de DNA Taxonômico , Mariposas/classificação , Mariposas/genética , Animais , Equador , Guiana Francesa , Dados de Sequência Molecular , Clima TropicalRESUMO
Globally, priority areas for biodiversity are relatively well known, yet few detailed plans exist to direct conservation action within them, despite urgent need. Madagascar, like other globally recognized biodiversity hot spots, has complex spatial patterns of endemism that differ among taxonomic groups, creating challenges for the selection of within-country priorities. We show, in an analysis of wide taxonomic and geographic breadth and high spatial resolution, that multitaxonomic rather than single-taxon approaches are critical for identifying areas likely to promote the persistence of most species. Our conservation prioritization, facilitated by newly available techniques, identifies optimal expansion sites for the Madagascar government's current goal of tripling the land area under protection. Our findings further suggest that high-resolution multitaxonomic approaches to prioritization may be necessary to ensure protection for biodiversity in other global hot spots.
Assuntos
Anuros , Biodiversidade , Conservação dos Recursos Naturais , Insetos , Lemur , Lagartos , Plantas , Algoritmos , Animais , Conservação dos Recursos Naturais/métodos , Ecossistema , Geografia , Madagáscar , ÁrvoresRESUMO
The satyrine butterfly subtribe Mycalesina has undergone one of the more spectacular evolutionary radiations of butterflies in the Old World tropics. Perhaps the most phenotypically pronounced diversification of the group has occurred in the Malagasy region, where 68 currently recognized species are divided among five genera. Here, we report the results of phylogenetic analyses of sequence data from the cytochrome c oxidase II and cytochrome b mitochondrial genes, for a total of 54 mycalesine taxa, mostly from Madagascar. These molecular data complement an existing data set based on male morphological characters. The molecular results support the suggestion from morphology that three of the five Malagasy genera are paraphyletic and support the monophyly of at least three major morphological clades. Novel hypotheses of terminal taxon pairs are generated by the molecular data. Dense taxon sampling appears to be crucial for elucidating phylogenetic relationships within this large radiation. A potentially complex scenario for the origin of Malagasy mycalesines is proposed.