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Article Reference Ants impact the composition of the aquatic macroinvertebrate communities of a myrmecophytic tank bromeliad
Located in Library / RBINS Staff Publications 2018
Article Reference Ant–plant relationships in the canopy of an Amazonian rainforest: the presence of an ant mosaic
Using different techniques to access the canopy of an Amazonian rainforest, we inspected 157 tree crowns for arboreal ants. Diversity statistics showed that our study sample was not representative of the tree and ant populations due to their high diversity in Amazonian rainforests, but permitted us to note that a representative part of territorially dominant arboreal ant species (TDAAs) was inventoried. Mapping of TDAA territories and use of a null model showed the presence of an ant mosaic in the upper canopy, but this was not the case in the sub-canopy. Among the TDAAs, carton-nesting Azteca dominated (52.98% of the trees) whereas ant-garden ants (Camponotus femoratus and Crematogaster levior), common in pioneer formations, were secondarily abundant (21.64% of the trees), and the remaining 25.37% of trees sheltered one of 11 other TDAAs. The distribution of the trees forming the upper canopy influences the structure of the ant mosaic, which is related to the attractiveness of some tree taxa for certain arboreal ant species and represents a case of diffuse coevolution.
Located in Library / RBINS Staff Publications 2018
Article Reference 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.
Located in Library / RBINS Staff Publications 2018
Article Reference 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.
Located in Library / RBINS Staff Publications 2018
Article Reference 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.
Located in Library / RBINS Staff Publications 2018
Article Reference Dipterological survey in Mitaraka Massif (French Guiana) reveals megadiverse dolichopodid fauna with an unprecedented species richness in Paraclius Loew, 1864 (Diptera: Dolichopodidae)
Located in Library / RBINS Staff Publications 2018
Article Reference 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.
Located in Library / RBINS Staff Publications 2018
Inproceedings Reference 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.
Located in Library / RBINS Staff Publications 2018
Article Reference Path and site effects deduced from merged transfrontier internet macroseismic data of two recent M4 earthquakes in NW Europe using a grid cell approach.
The online collection of earthquake reports in Europe is strongly fragmented across numerous seismological agencies. This paper demonstrates how collecting and merging online institutional macroseismic data strongly improves the density of observations and the quality of intensity shaking maps. Instead of using ZIP code Community Internet Intensity Maps, we geocode individual response addresses for location improvement, assign intensities to grouped answers within 100 km2 grid cells, and generate intensity attenuation relations from the grid cell intensities. Grid cell intensity maps are less subjective and illustrate a more homogeneous intensity distribution than communal ZIP code intensity maps. Using grid cells for ground motion analysis offers an advanced method for exchanging transfrontier equal-area intensity data without sharing any personal information. The applicability of the method is demonstrated on the felt responses of two clearly felt earthquakes: the 8 September 2011 ML 4.3 (Mw 3.7) Goch (Germany) and the 22 May 2015 ML 4.2 (Mw 3.7) Ramsgate (UK) earthquakes. Both events resulted in a non-circular distribution of intensities which is not explained by geometrical amplitude attenuation alone but illustrates an important low-pass filtering due to the sedimentary cover above the Anglo-Brabant Massif and in the Lower Rhine Graben. Our study illustrates the effect of increasing bedrock depth on intensity attenuation and the importance of the WNW–ESE Caledonian structural axis of the Anglo-Brabant Massif for seismic wave propagation. Seismic waves are less attenuated – high Q – along the strike of a tectonic structure but are more strongly attenuated – low Q – perpendicular to this structure, particularly when they cross rheologically different seismotectonic units separated by crustal-rooted faults.
Located in Library / No RBINS Staff publications
Article Reference Visualizing Cross-Sectional Data in a Real-World Context
If you could fly around your research results in three dimensions, wouldn’t you like to do it? Combining the capabilities of an open-source drawing tool with Google Earth maps allows researchers/geologists to visualize real-world cross-sectional data in three dimensions. Any spatial model displaying research results can be exported to a vertical figure to enable the results to be visualized spatially.
Located in Library / No RBINS Staff publications