Search publications of the members of the Royal Belgian institute of natural Sciences
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Aquatic life in Neotropical rainforest canopies: Techniques using artificial phytotelmata to study the invertebrate communities inhabiting therein
- In Neotropical rainforest canopies, phytotelmata ("plant-held waters") shelter diverse aquatic macroinvertebrate communities, including vectors of animal diseases. Studying these communities is difficult because phytotelmata are widely dispersed, hard to find from the ground and often inaccessible. We propose here a method for placing in tree crowns "artificial phytotelmata" whose size and shape can be tailored to different research targets. The efficacy of this method was shown while comparing the patterns of community diversity of three forest formations. We noted a difference between a riparian forest and a rainforest, whereas trees alongside a dirt road cutting through that rainforest corresponded to a subset of the latter. Because rarefied species richness was significantly lower when the phytotelmata were left for three weeks rather than for six or nine weeks, we recommend leaving the phytotelmata for twelve weeks to permit predators and phoretic species to fully establish themselves.
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How common is trophobiosis with hoppers (Hemiptera: Auchenorrhyncha) inside ant nests (Hymenoptera: Formicidae)? Novel interactions from New Guinea and a worldwide overview
- Trophobiotic interactions between ants and honeydew-providing hemipterans are widespread and are one of the key mechanisms that maintain ant super-abundance in ecosystems. Many of them occur inside ant nests. However, these cryptic associations are poorly understood, particularly those with hoppers (suborder Auchenorrhyncha). Here, we study tree-dwelling ant and Hemiptera communities in nests along the Mt. Wilhelm elevational gradient in Papua New Guinea and report a new case of this symbiosis between Pseudolasius Emery, 1887 ants and planthoppers. Furthermore, we provide a worldwide review of other ant-hopper interactions inside ant-built structures and compare their nature (obligate versus facultative) and distribution within the suborder Auchenorrhyncha. The novel interactions were observed in nests located at the tree trunk bases or along the whole trunks. Only immature planthopper stages were found inside nests, so full species identifications were not possible. However, nymph morphology and molecular data (18S and COI genes) indicated four related species of the family Flatidae (infraorder Fulgoromorpha) associated with Pseudolasius. Ant-planthopper occurrences were relatively rare (6% of all trophobiotic interactions) and peaked at mid-elevation (900 m above sea level). Pseudolasius was the only genus associated with planthoppers in the communities, with most cases monopolised by a single species, P. breviceps Emery, 1887. In contrast, all other ant genera tended various scale insects (Sternorrhyncha: Coccoidea). This apparent partner-specificity is rare: Worldwide, there are only about ten reported cases of obligate symbiosis in ant nests, distributed in five of the thirty-three Auchenorrhyncha families. Those trophobioses are randomly dispersed across the Auchenorrhyncha phylogeny, and thus likely originated multiple times independently. Further research on both adult and nymph hopper life history is needed to answer how these symbioses, notably rare in hoppers compared with other hemipterans, are maintained.
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Resource use and food preferences in understory ant communities along a complete elevational gradient in Papua New Guinea
- Elevational gradients provide an interesting opportunity for studying the effect of climatic drivers over short distances on the various facets of biodiversity. It is globally assumed that the decrease in species richness with increasing elevation follows mainly the decrease in ecosystem productivity, but studies on functional diversity still remain limited. Here, we investigated how resource use and food preferences by both individual ant species and communities foraging in the understory vary with elevation along a complete elevational gradient (200 to 3200 m asl). Five bait types reflecting some of the main ecosystem processes in which ants are involved were tested: mutualism (sucrose and melezitose), predation (live termites), and detritivory (crushed insects and chicken feces). The observed monotonic decrease in both species richness and occurrences with elevation increase was accompanied by changes in some of the tested ecosystem processes. Such variations can be explained by resource availability and/or resource limitation: Predation and bird feces removal decreased with increasing elevation possibly reflecting a decline in species able to use these resources, while insect detritivory and nectarivory were most probably driven by resource limitation (or absence of limitation), as their relative use did not change along the gradient. Consequently, resource attractiveness (i.e., food preferences at the species level) appears as an important factor in driving community structuring in ants together with the abiotic environmental conditions.
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Dipterological survey in Mitaraka Massif (French Guiana) reveals megadiverse dolichopodid fauna with an unprecedented species richness in Paraclius Loew, 1864 (Diptera: Dolichopodidae)
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Reconciling biodiversity and carbon stock conservation in an Afrotropical forest landscape
- Protecting aboveground carbon stocks in tropical forests is essential for mitigating global climate change and is assumed to simultaneously conserve biodiversity. Although the relationship between tree diversity and carbon stocks is generally positive, the relationship remains unclear for consumers or decomposers. We assessed this relationship for multiple trophic levels across the tree of life (10 organismal groups, 3 kingdoms) in lowland rainforests of the Congo Basin. Comparisons across regrowth and old-growth forests evinced the expected positive relationship for trees, but not for other organismal groups. Moreover, differences in species composition between forests increased with difference in carbon stock. These variable associations across the tree of life contradict the implicit assumption that maximum co-benefits to biodiversity are associated with conservation of forests with the highest carbon storage. Initiatives targeting climate change mitigation and biodiversity conservation should include both old-growth and regenerating forests to optimally benefit biodiversity and carbon storage.
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Variation in space and time of ant distribution among ground layers in an ecuadorian premontane forest
- Nearly half of the ant species present in a tropical forest are directly in contact with the ground for nesting or foraging, with evidence of vertical stratification among ground layers (i.e., surface, litter, and soil). How ants in each layer respond to environmental factors and to seasonality remains little studied. We hypothesized that ant species distribution varied spatially and seasonally among the three ground layers and that their distribution was distinctly affected by various abiotic and biotic factors. The ant distribution was analysed spatio-temporally: vertically (between the ground surface, leaf-litter, and mineral soil, using pitfalls, Winkler, and soil cores), horizontally (every meter along a 100 m transect) and seasonally (between the dry and the rainy seasons). Four environmental parameters were measured every meter along the transect: canopy openness, slope, leaf-litter volume and soil properties. Our results showed a clear vertical stratification, with distinct faunal composition in each layer and a strong seasonal effect. Stable distribution of several dominant species between seasons suggests a low nest relocation rate. During the dry season, higher ant richness and abundance were found in pitfall traps suggesting higher activity on the surface of the forest floor. Similarly, higher ant richness and abundance found in the soil during the dry season suggest the migration of drought-sensitive species downwards deeper into the soil. Species richness and dominant species distribution were related to distinct factors according to the layer considered; we found strong correlations between the quantity of leaf-litter and dominant ant species distribution and species richness in the leaf-litter layer, while no correlation was found with any factor in the soil layer. While soil properties influenced the ant distribution at the kilometer scale they had little influence at the meter scale.
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Gastropods as intermediate hosts of feline cardio-pulmonary parasites in Greece: preliminary results
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Taxonomy and phylogeny of the millipede family Pseudospirobolellidae in Southeast Asia
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African Bushmeat in Brussels: high prices and high levels of misidentification
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Seafood on the Belgian market: do you get what you are paying for?
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Barcoding organisms and tissues of policy concern: experiences from three years of BopCo
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DNA barcoding for forensics: experiences from three years of BopCo
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DNA barcoding to identify invasive alien species targeted by EU policies
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Identification of disease vectors from foreign deployment sites of the Belgian armed forces using DNA-based technologies
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A DNA-based approach to validate the identification of exotic mosquito species in Belgium
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DNA barcoding and identification of intermediate slug hosts in the framework of an epidemiological survey in Germany
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Prospections sur la « villa gallo-romaine du Sart », au lieu-dit La Hamaide, à Hautrage (B).
- Hautrage, une commune belge appartenant à l’entité de Saint-Ghislain, se situe dans la partie occidentale de la province du Hainaut. Plusieurs découvertes archéologiques, la plupart anciennes et souvent mal documentées, sont mentionnées sur son territoire1 . 1. Historique des recherches, le site (J. DUFRASNES) La première mention de ce site archéologique apparaît dans HAUBOUDIN 1898, p. 80. L’auteur, un archéologue amateur très actif habitant Stambruges2 , note alors : Villa du Sart.- Un chemin, qui porte encore le nom de chemin d’El Ville3 , indique la Villa du Sart qui est proche. Le cimetière était la nécropole de cette villa4 . Des notes manuscrites datées de janvier 19415 et un inventaire réalisé à l’occasion de l’entrée d’une partie de la collection d’Edmond Haubourdin aux Musées royaux d’Art et d’Histoire de Bruxelles mentionnent du matériel susceptible de provenir de la villa de la Hamaide à Hautrage, c’est-à-dire de la « villa du Sart » (fig. 1). Cependant, aucun des écrits laissés par cet archéologue ne relate qu’il obtint du matériel archéologique de ce site par acquisition, par des fouilles ou des prospections. Edmond Haubourdin ajoute : « Diverticulum.- Le chemin qui traverse le chemin de fer à la station de la Hamaide porte, au cadastre d’Hautrage, le nom de chaussée romaine. Cette chaussée [dont l’actuelle rue des Bats, à 300 mètres à l’est du site, serait un tronçon selon l’auteur ndlr] passait près de la villa et se dirigeait vers Bavay, probablement vers Chièvres, par Villerot, Sirault et Neufmaison, où elle se confondait avec le diverticulum qui venait de Condé par Stambruges. La grande largeur de cette voie de communication accuse son origine romaine »6
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Vertebrate Palaeoecology of the Pisco Formation (Miocene, Peru): Glimpses into the Ancient Humboldt Current Ecosystem
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Bistability in the redox chemistry of sediments and oceans
- For most of Earth’s history, the ocean’s interior was pervasively anoxic and showed occasional shifts in ocean redox chemistry between iron-buffered and sulfide-buffered states. These redox transitions are most often explained by large changes in external inputs, such as a strongly altered delivery of iron and sulfate to the ocean, or major shifts in marine productivity. Here, we propose that redox shifts can also arise from small perturbations that are amplified by nonlinear positive feedbacks within the internal iron and sulfur cycling of the ocean. Combining observational evidence with biogeochemical modeling, we show that both sedimentary and aquatic systems display intrinsic iron–sulfur bistability, which is tightly linked to the formation of reduced iron–sulfide minerals. The possibility of tipping points in the redox state of sediments and oceans, which allow large and nonreversible geochemical shifts to arise from relatively small changes in organic carbon input, has important implications for the interpretation of the geological rock record and the causes and consequences of major evolutionary transitions in the history of Earth’s biosphere
