Cockroaches in French Guiana Icteridae birds nests

We present here the cockroaches found in 55 nests of Icteridae birds in French Guiana in July 1998. Five species of cockroaches were found, Schultesia nitor (Zetoborinae), Phoetalia pallida (Blaberinae), Pelmatosilpha guianae (Blattinae), Chorisoneura n.sp. aff. gatunae (Pseudophyllodromiidae) and Epilampra grisea (Epilamprinae). The two dominant species, S. nitor and P. pallida, were found together in the same nests, and seem to be scavengers. The ecology of S. nitor was compared with those of S. lampyridiformis, a sister species found in the same type of habitat in Brazil

Application of image analysis to a quantitative micromorphological study of forest humus

International audienc

Des Hominidés dans la savane : Une Hypothèse testée grâce à la P.A.E.

International audienceL'hypothèse des origines et de l'adaptation de la famille des hominidés à la vie dans un milieu ouvert, lasavane, est devenue un véritable dogme en paléoanthropologie. A cause de cela, elle n'a jamais étévéritablement testée. Cependant, des travaux, notamment en morphologie fonctionnelle de l'appareillocomoteur, soulignent l'arboricolisme des premiers hominidés. Dans l'étude proposée, les différentesespèces d'hominidés et les faunes qui les accompagnent (primates, bovidés, carnivores, suidés) ont étéanalysées par la méthode P.A.E. (Parcimony Analysis of Endimicity). La première partie de cette étude aconsisté à adapter la P.A.E., déjà utilisée pour la biogéographie des faunes forestières (Colyn et Deleporte),aux groupes de faunes savanicoles. L'analyse concerne les faunes savanicoles de l'Afrique du sud et de l'est depuis 4 Ma (millions d'années).Elle met en évidence deux foyers d'endémisme savanicole, l'un en Afrique du sud, l'autre centré surl'Ethiopie, et une zone intermédiaire, autour du lac Victoria, qui subit des influences depuis ces deux foyers.Les trois époques retenues se situent entre 4 et 3 Ma, 2,5 et 1 Ma et l'actuelle. Les résultats obtenusmontrent une répartition des hominidés en accord avec celles des faunes savanicoles entre 2,5 Ma etl'actuelle. Par contre, les australopithèques ne présentent pas une paléobiogéographie compatible aveccelle des faunes savanicoles entre 4 et 3 Ma. Cela suggère que le taxon Australopithecus afarensis recouvreplusieurs espèces, et que leurs habitats respectifs, plus ou moins arborés, peuvent être la conséquence detransgressions forestières dans la région du lac Victoria à cette époque ou auparavant

Feature issue introduction : halide perovskites for optoelectronics

This joint Optics Express and Optical Materials Express feature issue presents a collection of nine papers on the topic of halide perovskites for optoelectronics. Perovskite materials have attracted significant attention over the past four years, initially for their outstanding performance in thin film solar cells, but more recently for applications in light-emitting devices (LEDs and lasers), photodetectors and nonlinear optics. At the same time, there is still much more to learn about the fundamental properties of these materials, and how these depend on composition, processing, and exposure to the environment. This feature issue provides a snapshot of some of the latest research in this rapidly-evolving multidisciplinary field.Published versio

Effect of biomass management regimes and wetting-drying cycles on soil carbon mineralization in a Sudano-Sahelian region

In Sudano-Sahelian regions, wetting-drying cycles may affect soil carbon mineralization in soil already poor in carbon. Conservation agriculture systems by improving crop residues return to soil is given to increase soil organic carbon and soil fertility. We studied the effect of biomass management regimes and wetting-drying cycles on soil carbon stocks and mineralization. A 50-day experiment was set up to compare carbon mineralization under two biomass management regimes, with and without mulch, using three soil wetting treatments. Wetting the soil and mulching increased soil carbon mineralization. However, wetting-drying cycles did not increase the soil carbon mineralization as compared with soils kept moist. During the experiment, the total carbon mineralization from the dry soils was low, 0.63 tC ha(-1) and 0.53 tC ha-I respectively for soils with and without mulch. Total carbon mineralization from soil without mulch was 1.40 tC ha(-1) with wetting-drying cycles and 1.51 tC ha(-1) for soils that were kept moist. Total carbon mineralization from soils with mulch was 1.70 tC ha(-1), regardless of whether the soils had wetting-drying cycles or were kept moist. In our context, characterized by very little crop residues and rapid mineralization of this biomass, the conservation agriculture systems do not seem sufficient to increase soil organic carbon stocks

The phylogeography of Lemniscomys striatus (Rodentia: Muridae) confirms a remarkable vicariant event in neighbouring savanna populations in Central Gabon

Our recent phylogeographic study on the strictly savanna small rodent Nannomys  minutoides revealed an unexpected pattern of divergence between populations  occupying neighbouring savanna islands in Central Gabon, suggesting the historical and continuing fragmentation of these savanna habitats. In this study, we test this hypothesis using comparative phylogeography with another species of savanna  rodent, Lemniscomys striatus, using nested clade analysis (NCA) on cytochrome b sequences of 53 individuals, particularly checking for vicariance patterns in the Lopé National Park region. Lemniscomys striatus is characterized by a local  structured pattern similar to that of N. minutoides. These new results further support the scenario of historical and ongoing fragmentation of the local savanna landscape which commenced in the upper Pleistocene, despite the repetitive savanna expansion episodes as documented by the landscape history. Geographic barriers most likely comprising forested areas, which prevent the mixing of local savanna rodent populations, must have persisted in this region. The presence of these  barriers could not have been inferred from global paleoclimatic and  paleoenvironmental analyses alone.Key words: Lemniscomys striatus, fragmented landscape, nested clade analysis, cytochrome b, Pleistocene