Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
PLoS One ; 13(3): e0194719, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29579129

RESUMO

Broad scale population estimates of declining species are desired for conservation efforts. However, for many secretive species including large carnivores, such estimates are often difficult. Based on published density estimates obtained through camera trapping, presence/absence data, and globally available predictive variables derived from satellite imagery, we modelled density and occurrence of a large carnivore, the jaguar, across the species' entire range. We then combined these models in a hierarchical framework to estimate the total population. Our models indicate that potential jaguar density is best predicted by measures of primary productivity, with the highest densities in the most productive tropical habitats and a clear declining gradient with distance from the equator. Jaguar distribution, in contrast, is determined by the combined effects of human impacts and environmental factors: probability of jaguar occurrence increased with forest cover, mean temperature, and annual precipitation and declined with increases in human foot print index and human density. Probability of occurrence was also significantly higher for protected areas than outside of them. We estimated the world's jaguar population at 173,000 (95% CI: 138,000-208,000) individuals, mostly concentrated in the Amazon Basin; elsewhere, populations tend to be small and fragmented. The high number of jaguars results from the large total area still occupied (almost 9 million km2) and low human densities (< 1 person/km2) coinciding with high primary productivity in the core area of jaguar range. Our results show the importance of protected areas for jaguar persistence. We conclude that combining modelling of density and distribution can reveal ecological patterns and processes at global scales, can provide robust estimates for use in species assessments, and can guide broad-scale conservation actions.


Assuntos
Panthera/fisiologia , Animais , Conservação dos Recursos Naturais , Ecossistema , Modelos Teóricos , Densidade Demográfica
2.
PLoS One ; 8(5): e63570, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23717448

RESUMO

We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages.


Assuntos
Borboletas/classificação , Magnoliopsida , Animais , Evolução Biológica , Comportamento Alimentar , Herbivoria , Funções Verossimilhança , Modelos Biológicos , Filogenia , Especificidade da Espécie
3.
Zootaxa ; 3716: 528-38, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-26106789

RESUMO

Four new species of Pedaliodes Butler (i.e., P. adrianae, n. sp., P. haydoni, n. sp., P. philinae, n. sp. and P. rodriguezi, n. sp.) are described from the high elevation cloud forests in the Frontino massif in the Colombian Western Cordillera and the northern part of the Central and Eastern Cordilleras. The affinities of these new species with other congeners are discussed. The total number of described species of Colombian Pronophilina is increased to 208, with a particularly high total number of species (88) and proportion of endemic species (26%) in the Western Cordillera.


Assuntos
Borboletas/anatomia & histologia , Borboletas/classificação , Distribuição Animal , Animais , Borboletas/fisiologia , Colômbia , Feminino , Masculino , Especificidade da Espécie
4.
J Med Entomol ; 47(5): 723-6, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20939364

RESUMO

The carrion beetle Oxelytrum discicolle (Brullé, 1840) has forensic importance in the Neotropical region. The age of their larvae can provide important information to estimate the minimum postmortem interval of the corpse. This study was designed to determine the larval stages of this species, using three morphological measurements, as follows: distance between dorsal stemmata, pronotal width, and total body length. Three instars were identified. Distance between dorsal stemmata and pronotal width were good discriminating variables to determine instars, whereas total length was widely variable. For each instar, intervals of three morphological measures are given.


Assuntos
Besouros/crescimento & desenvolvimento , Animais , Entomologia , Ciências Forenses , Larva/crescimento & desenvolvimento
5.
Forensic Sci Int ; 185(1-3): 107-9, 2009 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-19201556

RESUMO

Due to its necrophagy, the Neotropical beetle Oxelytrum discicolle (Brullé, 1840) is found in association with human corpses. Its biology can provide important information to determine the postmortem interval (PMI). We studied the life cycle of O. discicolle in the laboratory under three constant temperatures (15, 20 and 28 degrees C) and under natural conditions (mean T=18.5 degrees C) in a cloud forest in Altos de Pipe (10 degrees 20'N, 66 degrees 55'W) Miranda state, Venezuela. The total time required to complete development from egg to adult emergence shortened as temperatures increased, ranging from 40.00+/-2.73 days at 15 degrees C to 20.33+/-0.89 days at 28 degrees C. Developmental time in natural conditions was not significantly different from that obtained at 20 degrees C. This information would be useful to forensic entomology applied to criminal investigations in Venezuela and the Neotropical region.


Assuntos
Besouros/crescimento & desenvolvimento , Temperatura , Animais , Entomologia , Feminino , Antropologia Forense , Masculino , Venezuela
6.
Proc Natl Acad Sci U S A ; 105(17): 6356-61, 2008 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-18434549

RESUMO

Water reservoirs formed by the leaf axils of bromeliads are a highly derived system for nutrient and water capture that also house a diverse fauna of invertebrate specialists. Here we investigate the origin and specificity of bromeliad-associated insects using Copelatinae diving beetles (Dytiscidae). This group is widely distributed in small water bodies throughout tropical forests, but a subset of species encountered in bromeliad tanks is strictly specialized to this habitat. An extensive molecular phylogenetic analysis of Neotropical Copelatinae places these bromeliadicolous species in at least three clades nested within other Copelatus. One lineage is morphologically distinct, and its origin was estimated to reach back to 12-23 million years ago, comparable to the age of the tank habitat itself. Species of this clade in the Atlantic rainforest of southern Brazil and mountain ranges of northern Venezuela and Trinidad show marked phylogeographical structure with up to 8% mtDNA divergence, possibly indicating allopatric speciation. The other two invasions of bromeliad water tanks are more recent, and haplotype distributions within species are best explained by recent expansion into newly formed habitat. Hence, bromeliad tanks create a second stratum of aquatic freshwater habitat independent of that on the ground but affected by parallel processes of species and population diversification at various temporal scales, possibly reflecting the paleoclimatic history of neotropical forests.


Assuntos
Bromelia/parasitologia , Besouros/fisiologia , Simbiose , Árvores/parasitologia , Clima Tropical , Animais , Biodiversidade , Ecossistema , Evolução Molecular , Dados de Sequência Molecular , Filogenia
7.
Artigo em Inglês | MedCarib | ID: med-17701

RESUMO

Water reservoirs formed by the leaf axils of bromeliads are a highly derived system for nutrient and water capture that also house a diverse fauna of invertebrate specialists. Here we investigate the origin and specificity of bromeliad-associated insects using Copelatinae diving beetles (Dytiscidae). This group is widely distributed in small water bodies throughout tropical forests, but a subset of species encountered in bromeliad tanks is strictly specialized to this habitat. An extensive molecular phylogenetic analysis of Neotropical Copelatinae places these bromeliadicolous species in at least three clades nested within other Copelatus. One lineage is morphologically distinct, and its origin was estimated to reach back to 12-23 million years ago, comparable to the age of the tank habitat itself. Species of this clade in the Atlantic rainforest of southern Brazil and mountain ranges of northern Venezuela and Trinidad show marked phylogeographical structure with up to 8% mtDNA divergence, possibly indicating allopatric speciation. The other two invasions of bromeliad water tanks are more recent, and haplotype distributions within species are best explained by recent expansion into newly formed habitat. Hence, bromeliad tanks create a second stratum of aquatic freshwater habitat independent of that on the ground but affected by parallel processes of species and population diversification at various temporal scales, possibly reflecting the paleoclimatic history of neotropical forests.


Assuntos
Animais , Besouros/fisiologia , Biodiversidade , Bromelia/parasitologia , Ecossistema , Evolução Molecular , Dados de Sequência Molecular , Filogenia , Simbiose , Árvores/parasitologia , Clima Tropical , Trinidad e Tobago
8.
Proc Biol Sci ; 270 Suppl 1: S21-4, 2003 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-12952626

RESUMO

Butterflies of the genus Redonda Adams & Bernard (Lepidoptera: Nymphalidae: Satyrinae) are endemic to the Andes of Venezuela. They comprise a monophyletic group of five allopatric taxa, females of which show various degrees of wing reduction and ability to fly. The female of Redonda bordoni Viloria & Pyrcz sp. nov. appears to be brachypterous and incapable of sustained flight, a phenomenon previously unknown within the Rhopalocera.


Assuntos
Borboletas/classificação , Animais , Borboletas/anatomia & histologia , Feminino , Masculino , Venezuela , Asas de Animais/anatomia & histologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...