Forest destructuring as revealed by the temporal dynamics of fundamental species - Case study of Santa Genebra Forest in Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Variation in the composition of the tree population is common throughout the history of a well-preserved forest community, with this natural process maintaining the forest structure and giving rise to ecological processes necessary for the perpetuation of the ecosystem. However, fragmentation of forests can lead to the collapse of such a structure, especially when natural thinning of the dominant tree species is accompanied by other significant changes. This paper traces changes in the composition of the community of a forest of relevant ecological interest in Campinas (SP, Brazil) as that forest moves toward deterioration as indicated by a massive loss of individuals of fundamental species composing the canopy and subcanopy. The death of trees of the species traditionally forming the canopy, the result of natural processes, was probably intensified by anthropic factors, and led to a general destructuring of the community. The aim of this paper is to demonstrate that the dynamics of these fundamental species can be used as an indicator of the conservation of the ecosystem, as well as indicating the installation of a process which will lead to the collapse of the structure if adequate measures of adaptive management are not taken before the destructuring is irreversible. (C) 2013 Elsevier Ltd. All rights reserved.37A4044Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Intraspecific molecular variation in the seaweed fly Coelopa frigida consistent with behavioural distinctness of British and Swedish populations

The major aim of this study was to compare the intraspecific variation and genetic structure of the behaviourally distinct British and Swedish populations of the seaweed fly Coelopa frigida . C. frigida has been the subject of intense study into the basis of female choice. The behaviour of British females is consistent with a 'good genes' model, whereas that of the Swedish flies suggests a Fisher process, in which the difference between the former and the latter is defined by female choice increasing offspring viability in 'good genes' models. Through a study of variability in the mitochondrial cytochrome oxidase II gene from more than 600 flies, we show that there is clear differentiation at the molecular level between the two countries' populations, with an F (ST) of > 75% and no shared haplotypes. Tajima's test reveals an excess of rare variants relative to expectation, which, if not the result of selective sweep, indicates either a population expansion or purifying selection against weakly deleterious variants. Within the two populations, substantial subpopulation differentiation is observed in the UK, where there is also evidence of isolation by distance. Swedish populations exhibit lower variability, and no evidence of isolation by distance, with the latter result possibly being related to the continuous distribution of suitable habitat. The pattern of intraspecific variation is explainable by a combination of contemporary and also historical factors. British and Swedish populations may have been descended from at least two separate founding populations during the recolonization of these areas following Pleistocene glaciations

Stability of insecticide resistance due to amplification of esterase genes in Culex pipiens

International audienceThe stability of OP resistance due to amplification of esterase B1 or B2 was investigated in unselected strains. We show that resistance and amplification are both lost when strains are not homozygous for the presence of the amplified genes, due probably to fitness differences. In homozygous strains, both esterases remained amplified and expressed, and resistance was stable during at least 60 generations, indicating that events generating lower gene copy number are uncommon. Results are discussed with respect to the evolution of insecticide resistance