Phylogenetic signal and major ecological shifts in the ecomorphological structure of stream fish in two river basins in Brazil

We tested the contribution of the phylogenetic and specific components to the ecomorphological structure of stream fish from the upper Paraguai River and upper São Francisco River basins, and identified nodes in the phylogenetic tree at which major ecological shifts occurred. Fish were sampled between June and October of 2008 in 12 streams (six in each basin). In total, 22 species from the upper Paraguai River basin and 12 from the upper São Francisco River were analyzed. The ecomorphological patterns exhibited phylogenetic signal, indicating that the ecomorphological similarity among species is associated with the degree of relatedness. A strong habitat template is most likely to be the primary cause for a high phylogenetic signal. A significant contribution from the specific component was also detected, supporting the idea that the phylogenetic signal occurs in some clades for some traits, but not in others. The major ecological shifts were observed in the basal nodes, suggesting that ecological niche differences appear to accumulate early in the evolutionary history of major clades. This finding reinforces the role of key traits in the diversification of Neotropical fishes. Ecological shifts in recent groups could be related to morphological modifications associated with habitat use.

Examinamos a contribuição dos componentes filogenético e específico para a estrutura ecomorfológica de peixes de riacho das bacias do alto rio Paraguai e do alto rio São Francisco, e identificamos os nós na árvore filogenética onde ocorreram as maiores mudanças ecológicas. Os peixes foram amostrados entre junho e outubro de 2008 em 12 riachos (seis em cada bacia). No total, 22 espécies do alto rio Paraguai foram analisadas e 12 do alto rio São Francisco. O padrão ecomorfológico exibiu sinal filogenético, indicando que a similaridade ecomorfológica entre as espécies está associada com o grau de parentesco. Um forte 'habitat template' é provavelmente a maior causa para o forte sinal filogenético. Foi detectada uma significativa contribuição do componente específico, apoiando a ideia de que o sinal filogenético ocorre em alguns clados para alguns traços, mas não em outros. As maiores mudanças ecológicas foram observadas nos nós basais sugerindo que as diferenças do nicho ecológico em peixes de riacho parecem acumular-se cedo na história evolutiva dos clados e reforça o papel de traços fundamentais na diversificação de peixes Neotropicais. Mudanças ecológicas em grupos recentes podem estar relacionadas com uma modificação morfológica associada ao uso do habitat.

Breeding habitats characterization of anopheles mosquito [diptera: culicidae] in Najran province, Saudi Arabia

An ecological study on mosquito larval breeding habitats was conducted in Najran Region, Saudi Arabia during 2005-2006 to study the breeding habitats determinants for Anopheles mosquito in two ecological types [cities and villages]. The increased rate of developmental activities promotes man-made mosquito breeding habitats, which regulate Anopheles mosquito abundance or absence. The linear regression analysis revealed that An. gambiae s.L abundance or absence is regulated by the presence of natural water habitats, which has the highest rate [79%] in villages. Other ecological, biological and physiochemical predictors for Anopheles mosquito larvae abundance or absence in the two ecological types were discussed