The representation of the world in national Arab news agencies: an exploration of (trans)national networks in the official Arab media

The purpose of this paper is to draw a map of the representation of the world and of Arab states as reflected by the countries of the region. To do so, we have analysed the news (4,093 news randomly collected on February and August 2005) produced by the governments of the Arab states through their national news agencies. Several regional and world maps had been constructed to show the official Arab representation of the World, the Arab countries conflict agenda, the persistence of colonial ties (with the European metropolis) and the emergence of new relationships (Asian countries). The representation of the world that appeared in the analysis focuses its interest on the USA, the war in Iraq, the Israel-Palestine conflict, the United Kingdom, France, and Iran. The Arab regional powers organise the flow of information (Saudi Arabia and Egypt) and the colonial past determines the current structure of communication (French-speaking bloc and English-speaking bloc).

Beta diversity at multiple hierarchical levels: explaining the high diversity of scarab beetles in tropical montane forests

Aim: High gamma diversity in tropical montane forests may be ascribed to high geographical turnover of community composition, resulting from population isolation that leads to speciation. We studied the evolutionary processes responsible for diversity and turnover in assemblages of tropical scarab beetles (Scarabaeidae) by assessing DNA sequence variation at multiple hierarchical levels. Location: A 300-km transect across six montane forests (900–1100 m) in Costa Rica. Methods: Assemblages of Scarabaeidae (subfamilies Dynastinae, Rutelinae, Melolonthinae) including 118 morphospecies and > 500 individuals were sequenced for the cox1 gene to establish species limits with a mixed Yule–coalescent method. A species-level phylogenetic tree was constructed from cox1 and rrnL genes. Total diversity and turnover among assemblages were then assessed at three hierarchical levels: haplotypes, species and higher clades. Results: DNA-based analyses showed high turnover among communities at all hierarchical levels. Turnover was highest at the haplotype level (community similarity 0.02–0.12) and decreased with each step of the hierarchy (species: 0.21–0.46; clades: 0.41–0.43). Both compositional and phylogenetic similarities of communities were geographically structured, but turnover was not correlated with distance among forests. When three major clades were investigated separately, communities of Dynastinae showed consistently higher alpha diversity, larger species ranges and lower turnover than Rutelinae and Melolonthinae. Main conclusions: Scarab communities of montane forests show evidence of evolutionary persistence of communities in relative isolation, presumably tracking suitable habitats elevationally to accommodate climatic changes. Patterns of diversity on all hierarchical levels seem to be determined by restricted dispersal, and differences in Dynastinae could be explained by their greater dispersal ability. Community-wide DNA sequencing across multiple lineages and hierarchical levels reveals the evolutionary processes that led to high beta diversity in tropical montane forests through time.