Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 4 de 4
Filtrar
Mais filtros










Filtros aplicados
Base de dados
Tipo de estudo
Intervalo de ano de publicação
1.
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
2.
Phytochemistry ; 40(2): 735-38, Oct. 1995.
Artigo em Inglês | MedCarib | ID: med-4589

RESUMO

The novel assingment of 13C and 1HNMR data for cadina-4,10(15)-dien-3-one obtained from Hyptis verticillata is presented. The study revealed that cadina-4,10(15)-dien-3-one possesses chemosterilant activities against the economically important cattle tick, Boophilus microplus, and toxic action against adult Cylas formicarius the most destructive pest of sweet potato (I pomoea sp.) (AU)


Assuntos
21003 , Feminino , Masculino , Besouros , Inseticidas , Naftalenos/química , Carrapatos , Isótopos de Carbono , Bovinos , Hidrogênio , Estrutura Molecular , Naftalenos/isolamento & purificação , Naftalenos/toxicidade , Espectroscopia de Ressonância Magnética , Plantas
3.
Plant Foods Hum Nutr ; 43(2): 105-14, Mar. 1993.
Artigo em Inglês | MedCarib | ID: med-8490

RESUMO

Protein quality of sorghum grains having 25, 50 and 75 percent infestation caused by mixed population of Trogoderma granarium Everts and Rhizopertha dominica Fabricius was biologically evaluated by rat growth and nitrogen balance studies. Feeding of diet containing insect infested sorghum grains (50 and 75 percent) resulted in marked decrease in food intake, protein intake, gain in body weight, food efficiency ratio, protein efficiency ratio, nitrogen consumption, nitrogen absorption, biological value, net protein utilization, dry matter digestibility, net protein retention and protein retention efficiency. These parameters showed negative association with insect infestation levels. However, 25 percent level of grain infestation did not affect these parameters significantly (AU)


Assuntos
Camundongos , Ratos , 21003 , Masculino , Besouros , Grão Comestível/análise , Contaminação de Alimentos , Proteínas de Plantas , Análise de Variância , Ingestão de Alimentos , Nitrogênio/urina , Valor Nutritivo , Proteínas de Plantas/metabolismo , Ratos Endogâmicos/crescimento & desenvolvimento , Aumento de Peso
4.
Plant Foods Hum Nutr ; 43(1): 45-54, Jan. 1993.
Artigo em Inglês | MedCarib | ID: med-8491

RESUMO

Total soluble sugar, reducing sugar, non-reducing sugar and starch contents of wheat, maize and sorghum grains were affected adversely at 25, 50 and 75 percent insect infestation caused by Trogoderma granarium Everts and Rhizopertha dominica Fabricius, separately and mixed population. R. dominica caused significant (P < 0.05) reduction in available carbohydrates at 50 and 75 percent. Mixture of both insect species caused intermediate losses. Storage of cereal grains up to 4 months resulted in substantial increase in sugars and decrease in starch content, but storage for a shorter period of time did not cause any significant changes in levels of carbohydrates (Summary)


Assuntos
21003 , Besouros/crescimento & desenvolvimento , Carboidratos/análise , Grão Comestível/análise , Contaminação de Alimentos , Conservação de Alimentos , Grão Comestível/parasitologia , Zea mays/análise , Zea mays/parasitologia , Amido/análise , Triticum/análise , Triticum/parasitologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...