Made available in DSpace on 2014-08-20T14:31:32Z (GMT). No. of bitstreams: 1 dissertacao_sabrina_pires_capa.pdf: 403567 bytes, checksum: 5752dd89517a54f40cd0632e1db1c1c6 (MD5) Previous issue date: 2007-03-30 / The blowflies are the first insects to compose the faunistic succession of human cadavers, thus helping to determine the postmortem interval (PMI). However, failing to consider larval post-feeding dispersal can compromise medical-criminal inquiries. In order to investigate the relationship between post- feeding Lucilia sericata larvae and their weight, radial dispersion and depth, an artificial arena was built simulating the natural environment. We observed a difference in mean pupal weight between males (30.28mg) and females (32.35mg). We also observed that the majority of pupae were recovered a distance of 33 to 45cm from the center of the arena, and at a depth of 6 to 8cm from the surface. However, we observed no differences in radial dispersion and depth of pupation between males, females or unviable individuals. Correlation analysis between weight and distance (r = 0.246) and between weight and depth (r = 0.321) was directly proportional, suggesting that heavier pupae dispersed farther and deeper than lighter pupae. The experiment also allowed us to conclude that a circular arena permitted larval dispersion all directions. / Os dípteros califorídeos são os primeiros indivíduos a compor a sucessão faunística dos cadáveres humanos auxiliando assim na estimativa do intervalo pós- morte. Porém, a não consideração da dispersão pós-alimentar de larvas pode comprometer as investigações médico-criminais. Diante disto uma arena circular, simulando o ambiente natural, foi montada em laboratório a fim de verificar-se a dispersão larval radial pós-alimentar de Lucilia sericata, tentando assim estabelecer relações entre as variáveis peso, distância e profundidade de enterramento na arena. Os resultados demonstraram que a maioria das pupas foram recuperadas a uma profundidade compreendida entre 6cm e 8cm e a uma distância entre 33cm e 45cm do centro da arena. Não houve diferenças significativas quanto a propagação e profundidade de enterramento de machos, fêmeas e indivíduos inviáveis. Com relação ao peso, verificou-se que a média das fêmeas (x = 32,35mg) foi superior a dos machos (x = 30,28mg). A análise de correlação entre peso e distância percorrida (r = 0,246) e entre peso e profundidade (r = 0,321) foi diretamente proporcional, ou seja pupas mais pesadas propagaram e se aprofundaram mais. O experimento permitiu ainda concluir que uma arena circular possibilita o deslocamento das larvas em todas as direções.

Echinocardium cordatum (Pennant 1777) oursin irrégulier abondant des zones côtières tempérées a longtemps été considéré comme une espèce cosmopolite dont la vaste aire de distribution était la conséquence directe des capacités de dispersion de sa larve planctotrophe. L’étude couplée des caractéristiques génétiques [génomes mitochondrial et nucléaire (introns+microsatellites)], morphologiques (étude basée sur 20 indices morphométriques) et écologiques (distribution géographique à petite ou grande échelle, et cycle de maturation gonadique) a révélé la présence d’un complexe d’espèces jumelles dont la différenciation génétique est accompagnée d’une différenciation morphologique statistique ainsi que de différenciations écologiques plus ou moins fines. Ces espèces occupent des aires de distribution limitées (clade A : Atlantique, clade SP : Pacifique Sud, clade NP : Pacifique Nord, clade B2 : Méditerranée, et clade B1 : Méditerranée et côtes atlantiques de l’Ibérie). D’après la reconstruction de l’histoire évolutive de ce complexe, à partir des données paléontologiques et moléculaires, ces espèces auraient divergé il y a 3 (B1-B2) à 10 (A-reste) millions d’années sous l’effet de perturbations géologiques et paléoclimatiques (fermeture de la Téthys, crise messinienne de salinité et glaciations Plio-Pléistocène). Le polymorphisme morphologique et moléculaire apparaît réduit chez B1 suggérant un effectif efficace historique de cette espèce réduit. L’analyse des flux géniques contemporains révèle que les clades A et B1 échangent toujours des gènes, alors que les clades B1 et B2, ont mis en place un isolement reproducteur efficace empêchant l’hybridation. Par ailleurs, les capacités de dispersion des espèces de ce complexe sont importantes (plus de 3000 km), mais moindres comparées à d’autres espèces du genre, notamment E. mediterraneum, qui bien qu’ayant subi les mêmes évènements géologiques n’a pas formé d’espèce depuis son apparition il y aurait 28 millions d’années. D’un point de vue évolutif, les taxons à forte capacité de dispersion présenteraient des tailles efficaces de populations importantes, ainsi qu’une aire de répartition étendue et peu de différentiation génétique entre localités ; autant de caractéristiques qui devraient ralentir la vitesse de spéciation dans ces taxons. Si cette hypothèse semble se vérifier chez E. mediterraneum, il n’en est pas de même chez E. cordatum qui malgré des effectifs efficaces apparemment importants et une différenciation des populations à l’échelle régionale faible, présente une dynamique se spéciation plus rapide. Il faut envisager que d’autres caractéristiques soient à l’origine de cette différence de dynamique de spéciation, et la comparaison des exigences écologiques des deux taxons ainsi que l’isolement de la molécule responsable de la réaction acrosomique, la bindine, pourraient apporter des éléments de réponse aux nouvelles questions soulevées. / Echinocardium cordatum (Pennant 1777) an abundant irregular sea urchin from the coastal temperate zones has long been considered as a cosmopolitan species which wide distribution area was the direct consequence of its planktotrophic larvae high dispersal abilities. A combined study of the genetic [mitochondrial and nuclear genomes (introns+microsatellites)], morphologic (based on 20 morphometric indices) and ecologic (geographic distribution at fine or large scale, and gonad maturation cycle) characteristics reveals that this taxon is a complex of cryptic species for which genetic differentiations concurred with morphological and ecological ones. The different species each occupy a limited geographic areas (clade A : Atlantic, clade SP : South Pacific, clade NP : North Pacific, clade B2 : Mediterranean sea, et clade B1 : Mediterranean sea and Atlantic coasts of Iberia). According to the complex species evolutionary history reconstruction, based on fossils and molecular data, the different species diverged between 3 (B1-B2) and 10 (A-rest) million years ago, driven by geologic and paleoclimatic perturbations (Tethys closure, messinian salinity crisis, Plio-Pleistocene glaciations). Molecular and morphologic polymorphisms appear reduced in B1, suggesting a reduced historical effective size. The contemporaneous genetic flux analysis reveals that clades A and B1 exchange genes whereas clades B1 and B2 developed an efficient reproductive isolation preventing hybridization. Though dispersal abilities of the complex species are high (more than 3000 km), they appear to be smaller than those of other species of the same genera, particularly E. mediterraneum which undergone the same geological perturbations without splitting into several species since its appearance some 28 million years ago. From an evolutionary point of view, taxa with high dispersal abilities should exhibit important population effective sizes, wide distribution areas and weak genetic differentiation between localities, properties that should slow species formation within these taxa. If this hypothesis seems verified in E. mediterraneum, it is not the case in E. cordatum for which the apparent high effective size and weak regional structure contrast with the fast speciation dynamics. It seems that other characteristics might be responsible for the speciation dynamic differences, and the comparison of the two taxa ecological requirements, as well as the isolation of the gene coding for the protein responsible of the sperm specific attachment, the bindin, should bring elements to answer these questions.