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Author Bleron, L.; Duchanois, G.; Thibaut, B.
Title Characteristic properties of embedding strength for the nailing of the gonfolio rose (Qualea rosea Aubl.) Type Journal Article
Year (up) 2008 Publication Holzforschung Abbreviated Journal Holzforschung
Volume 62 Issue 1 Pages 86-90
Keywords embedding strength; Eurocode V; nail
Abstract Experimental results are presented with single nail joints of gonfolo rose which were loaded at different grain angles and compared to results obtained by Eurocode V. A wide range of embedding strength tests was conducted. The embedding behaviour across the grain was also investigated with a specific test apparatus. The results were analysed and modelled in terms of strength. Initial loading and unloading stiffness of the timber have been taken into account. The embedment strength of the nails varied according to the angle between the direction of loading and that to the grain. This work is part of a larger research project to establish a computer program for the prediction of stiffness and limit strengths of all timber-to-timber and timber-to-steel joints.
Address [Bleron, Laurent] LABOMAP ENSAM, F-71250 Poret De Paris, Cluny, France, Email: laurent.bleron@cluny.ensam.fr
Corporate Author Thesis
Publisher WALTER DE GRUYTER & CO Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0018-3830 ISBN Medium
Area Expedition Conference
Notes ISI:000252041400013 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 144
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Author Schimann, H.; Ponton, S.; Hattenschwiler, S.; Ferry, B.; Lensi, R.; Domenach, A.M.; Roggy, J.C.
Title Differing nitrogen use strategies of two tropical rainforest late successional tree species in French Guiana: Evidence from N-15 natural abundance and microbial activities Type Journal Article
Year (up) 2008 Publication Soil Biology & Biochemistry Abbreviated Journal Soil Biol. Biochem.
Volume 40 Issue 2 Pages 487-494
Keywords soil; litter; nitrate; nitrification; tree rooting; N-15; Eperua falcata; Dicorynia guianensis; tropical forest
Abstract Previous studies in lowland tropical rainforests of French Guiana showed that, among non-N-2-fixing trees, two groups of late successional species contrasting in their leaf N-15 natural abundance coexist, suggesting two different main ways of nitrogen acquisition. Two abundant late-successional species typically co-occurring in rainforests in French Guiana, namely Eperua falcata and Dicorynia guianensis, were chosen as representative of each group. Stable isotope techniques and measurements of potentials of microbial N transformation were performed to assess to what extent leaf N-15 natural abundance of these species could be related to (i) delta N-15 signatures of soil mineral N sources and (ii) the capacity of soil to express nitrification and denitrification (both processes being directly involved in the balance between NH4+ and NO3-). Soil delta N-15-NH4+ was roughly similar to leaf delta N-15 of D. guianensis (around 3.5 parts per thousand), suggesting a preferential use of NH4+, whereas in E. falcata, leaf delta N-15 values were closer to root delta N-15-NO3- values (0.2 and -2.0 parts per thousand, respectively), suggesting a preferential use of NO3-. These differences in N source utilization were not accompanied by differences in availability in soil NO3- or in intensity of microbial functions responsible for soil N mineral evolution. However, (i) under both tree species, these functions showed clear spatial partitioning, with denitrification occurring potentially in soil and nitrification in the litter layer, and (ii) E falcata fine roots colonized the litter layer much more strongly than D. guianensis fine roots. This strongly suggests that (i) the contrasted leaf delta N-15 values found in the two late-successional species reveal distinct N acquisition strategies and (ii) the ability of roots to predominantly exploit the litter layer (E falcata) or the soil (D. guianensis) may constitute an important explanation of the observed differences. A complementarity between tree species, based on mineral N resource partitioning (itself resulting from a spatially structured location of the microbial functions responsible for the balance between NH4+ and NO3-), n thus be supposed. (c) 2007 Elsevier Ltd. All rights reserved.
Address [Schimann, Heidy; Ponton, Stephane; Domenach, Anne-Marie; Roggy, Jean-Christophe] UMR Ecol Forets Guyane, F-97387 Kourou, French Guiana, Email: heidy_schimann@cirad.fr
Corporate Author Thesis
Publisher PERGAMON-ELSEVIER SCIENCE LTD Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0038-0717 ISBN Medium
Area Expedition Conference
Notes ISI:000251655800021 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 146
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Author Grangier, J.; Orivel, J.; Negrini, M.; Dejean, A.
Title Low intraspecific aggressiveness in two obligate plant-ant species Type Journal Article
Year (up) 2008 Publication Insectes Sociaux Abbreviated Journal Insect. Soc.
Volume 55 Issue 3 Pages 238-240
Keywords aggressiveness; Allomerus; myrmecophytes; plant-ants; recognition ability
Abstract Little is known about the aggressiveness of plant-ants typically living in isolated trees nor about how that aggressiveness varies based on this isolation. Here, we examine intra- and interspecific aggressiveness between workers of two Allomerus species associated with two different myrmecophytes. In both cases, the level of intraspecific aggressiveness is very low whatever the distance separating the tested nests, while interspecific conflicts are always violent. Similar patterns of aggressiveness have been reported in various ant species, but the strictly arboreal life of Allomerus ants associated with the isolation of their adult colonies highlight different ecological conditions that might explain the lack of aggressiveness between conspecifics.
Address [Grangier, J.; Orivel, J.; Negrini, M.; Dejean, A.] Univ Toulouse 3, CNRS, UMR 5174, Lab Evolut & Diversite Biol, F-31062 Toulouse 9, France, Email: grangier@cict.fr
Corporate Author Thesis
Publisher BIRKHAUSER VERLAG AG Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0020-1812 ISBN Medium
Area Expedition Conference
Notes ISI:000258959300004 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 208
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Author Dejean, A.; Grangier, J.; Leroy, C.; Orivel, J.; Gilbernau, M.
Title Nest site selection and induced response in a dominant arboreal ant species Type Journal Article
Year (up) 2008 Publication Naturwissenschaften Abbreviated Journal Naturwissenschaften
Volume 95 Issue 9 Pages 885-889
Keywords ant-plant relationships; biotic defense; induced responses; predation
Abstract It is well known that arboreal ants, both territorially dominant species and plant ants (e.g., species associated with myrmecophytes or plants housing them in hollow structures), protect their host trees from defoliators. Nevertheless, the presence of an induced defense, suggested by the fact that the workers discovering a leaf wound recruit nestmates, is only known for plant ants. Based on the results from a field study, we show here (1) that colonies of Azteca chartifex, a territorially dominant, neotropical arboreal ant species, mostly selected Goupia glabra (Goupiaceae) trees in which to build their principal carton nests and (2) that plant signals induced workers to recruit nestmates, which patrol the leaves, likely providing the plant with a biotic defense. Furthermore, the number of recruited workers was clearly higher on G. glabra, their most frequently selected host tree species, than on other tree species. These results show that contrary to what was previously believed, induced responses are also found in territorially dominant arboreal ants and so are not limited to the specific associations between myrmecophytes and plant ants.
Address [Dejean, Alain] CNRS Guyane, UPS 5621, F-97300 Cayenne, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher SPRINGER Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-1042 ISBN Medium
Area Expedition Conference
Notes ISI:000258675700013 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 209
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Author Dejean, A.; Moreau, C.S.; Kenne, M.; Leponce, M.
Title The raiding success of Pheidole megacephala on other ants in both its native and introduced ranges Type Journal Article
Year (up) 2008 Publication Comptes Rendus Biologies Abbreviated Journal C. R. Biol.
Volume 331 Issue 8 Pages 631-635
Keywords invasive ants; predation; raiding other ants; recruitment
Abstract We studied the behaviour of the invasive African myrmicine ant, Pheidole megacephala, when confronted with colonies of other common ant species in Cameroon, a part of its native range, and in Mexico, where it has been introduced. P. megacephala raided the nests of the other ants in both cases. Eleven species out of 12 put up a rather strong resistance to raiding P. megacephala workers in Cameroon compared to only three species out of 11 in Mexico, where only colonies of Solenopsis geminata, Dorymyrmex pyramicus and Dolichoderus bispinosus resisted these raids. We conclude that P. megacephala's heightened ability to successfully raid colonies of competing ants may help explain its success and the decline of native ants in areas where it has been introduced.
Address [Dejean, Alain] CNRS Guyane, UPS 2561, F-97300 Cayenne, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1631-0691 ISBN Medium
Area Expedition Conference
Notes ISI:000258523200008 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 210
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Author Coutand, C.; Dupraz, C.; Jaouen, G.; Ploquin, S.; Adam, B.
Title Mechanical stimuli regulate the allocation of biomass in trees: Demonstration with young Prunus avium trees Type Journal Article
Year (up) 2008 Publication Annals of Botany Abbreviated Journal Ann. Bot.
Volume 101 Issue 9 Pages 1421-1432
Keywords Prunus avium; growth; mechanical stress; bending; biomass; shoot/root ratio; wind; shelter
Abstract Background and Aims Plastic tree-shelters are increasingly used to protect tree seedlings against browsing animals and herbicide drifts. The biomass allocation in young seedlings of deciduous trees is highly disturbed by common plastic tree-shelters, resulting in poor root systems and reduced diameter growth of the trunk. The shelters have been improved by creating chimney-effect ventilation with holes drilled at the bottom, resulting in stimulated trunk diameter growth, but the root deficit has remained unchanged. An experiment was set up to elucidate the mechanisms behind the poor root growth of sheltered Prunus avium trees. Methods Tree seedlings were grown either in natural windy conditions or in tree-shelters. Mechanical wind stimuli were suppressed in ten unsheltered trees by staking. Mechanical stimuli (bending) of the stem were applied in ten sheltered trees using an original mechanical device. Key Results Sheltered trees suffered from poor root growth, but sheltered bent trees largely recovered, showing that mechano-sensing is an important mechanism governing C allocation and the shoot-root balance. The use of a few artificial mechanical stimuli increased the biomass allocation towards the roots, as did natural wind sway. It was demonstrated that there was an acclimation of plants to the imposed strain. Conclusions This study suggests that if mechanical stimuli are used to control plant growth, they should be applied at low frequency in order to be most effective. The impact on the functional equilibrium hypothesis that is used in many tree growth models is discussed. The consequence of the lack of mechanical stimuli should be incorporated in tree growth models when applied to environments protected from the wind (e.g. greenhouses, dense forests).
Address [Coutand, Catherine; Jaouen, Gaelle; Ploquin, Stephane; Adam, Boris] Univ Clermont Ferrand, INRA, UMR PIAF, F-63100 Clermont Ferrand, France, Email: coutand@clermont.inra.fr
Corporate Author Thesis
Publisher OXFORD UNIV PRESS Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-7364 ISBN Medium
Area Expedition Conference
Notes ISI:000255987500013 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 211
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Author Leroy, C.; Jauneau, A.; Quilichini, A.; Dejean, A.; Orivel, J.
Title Comparison between the anatomical and morphological structure of leaf blades and foliar domatia in the ant-plant Hirtella physophora (Chrysobalanaceae) Type Journal Article
Year (up) 2008 Publication Annals of Botany Abbreviated Journal Ann. Bot.
Volume 101 Issue 4 Pages 501-507
Keywords anatomy; ant-plant mutualism; Chrysobalanaceae; extra-floral nectaries; French Guiana; Hirtella physophora; secondary domatia
Abstract Background and Aims Myrmecophytes, or ant-plants, are characterized by their ability to shelter colonies of some ant species in hollow structures, or ant-domatia, that are often formed by hypertrophy of the internal tissue at specific locations (i.e. trunk, branches, thorns and leaf pouches). In Hirtella physophora (Chrysobalanaceae), the focal species of this study, the ant-domatia consist of leaf pouches formed when the leaf rolls over onto itself to create two spheres at the base of the blade. Methods The morphological and anatomical changes through which foliar ant-domatia developed from the laminas are studied for the first time by using fresh and fixed mature leaves from the same H. physophora individuals. Key results Ant-domatia were characterized by larger extra-floral nectaries, longer stomatal apertures and lower stomatal density. The anatomical structure of the domatia differed in the parenchymatous tissue where palisade and spongy parenchyma were indistinct; chloroplast density was lower and lignified sclerenchymal fibres were more numerous compared with the lamina. In addition, the domatia were thicker than the lamina, largely because the parenchymatous and epidermal cells were enlarged. Conclusion Herein, the morphological and anatomical changes that permit foliar ant-domatia to be defined as a specialized leaf structure are highlighted. Similarities as well as structural modifications in the foliar ant-domatia compared with the lamina are discussed from botanical, functional and mutualistic points of view. These results are also important to understanding the reciprocal evolutionary changes in traits and, thus, the coevolutionary processes occurring in insect-plant mutualisms.
Address [Leroy, Celine; Quilichini, Angelique; Dejean, Alain; Orivel, Jerome] Univ Toulouse 3, CNRS, UMR 5174, Lab Evolut & Diversite Biol, F-31062 Toulouse 9, France, Email: orivel@cict.fr
Corporate Author Thesis
Publisher OXFORD UNIV PRESS Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0305-7364 ISBN Medium
Area Expedition Conference
Notes ISI:000253489700003 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 212
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Author Dejean, A.; Djieto-Lordon, C.; Orivel, J.
Title The plant ant Tetraponera aethiops (Pseudomyrmecinae) protects its host myrmecophyte Barteria fistulosa (Passifloraceae) through aggressiveness and predation Type Journal Article
Year (up) 2008 Publication Biological Journal of the Linnean Society Abbreviated Journal Biol. J. Linnean Soc.
Volume 93 Issue 1 Pages 63-69
Keywords ants; plant protection; territorial aggressiveness
Abstract Plant ants generally provide their host myrmecophytes (i.e. plants that shelter a limited number of ant species in hollow structures) protection from defoliating insects, but the exact nature of this protection is poorly known. It was with this in mind that we studied the association between Tetraponera aethiops F. Smith (Pseudomyrmecinae) and its specific host myrmecophyte Barteria fistulosa Mast. (Passifloraceae). Workers bore entrances into the horizontal hollow branches (domatia) of their host B. fistulosa, near the base of the petiole of the alternate horizontal leaves. They then ambush intruders from the domatia, close to these entrances. After perceiving the vibrations caused when an insect lands on a leaf, they rush to it and sting and generally spreadeagle the insect (only small caterpillars are mastered by single workers). Among the insects likely to defoliate B. fistulosa, adult leaf beetles and large katydids were taken as prey and cut up; single workers then retrieved some pieces, whereas other workers imbibed the prey's haemolymph. Other insects known to defoliate this plant, if unable to escape, were killed and discarded. Small Acrea zetes L. caterpillars were stung and then discarded by single workers; whereas locusts of different sizes were mastered by groups of workers that stung and spreadeagled them before discarding them (although a part of their haemolymph was imbibed). More workers were involved and more time was necessary to master insects taken as prey than those attacked and discarded. Consequently, the protection T. aethiops workers provide to their host B. fistulosa from defoliating insects results from predation, but more often from a type of aggressiveness wherein insects are killed and then discarded. (c) 2008 The Linnean Society of London.
Address [Dejean, Alain] CNRS Guyane, UPS 2561, F-97300 Cayenne, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher BLACKWELL PUBLISHING Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0024-4066 ISBN Medium
Area Expedition Conference
Notes ISI:000251738300007 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 213
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Author Christensen-Dalsgaard, K.K.; Ennos, A.R.; Fournier, M.
Title Interrelations between hydraulic and mechanical stress adaptations in woody plants Type Journal Article
Year (up) 2008 Publication Plant Signaling and Behavior Abbreviated Journal Plant. Signal. Behav.
Volume 3 Issue 7 Pages 463-465
Keywords Conductivity; Modulus of elasticity; Strain; Tree ecophysiology; Tropical trees; Wood anatomy; Yield stress
Abstract The fields of plant water relations and plant biomechanics have traditionally been studied separately even though often the same tissues are responsible for water transport and mechanical support. There is now increasing evidence that hydraulic and mechanical adaptations may influence one another. We studied the changes in the hydraulic and mechanical properties of the wood along lateral roots of two species of buttressed trees. In these roots, the mechanical contstraints quantified by strain measurements are known to decrease distally. Further, we investigated the effect of mechanical loading on the vessel anatomy in these and four other species of tropical trees. We found that as the strain decreased, the wood became progressively less stiff and strong but the conductivity increased exponentially. This was reflected in that adaptations towards re-enforcing mechanically loaded areas resulted in xylem with fewer and smaller vessels. In addition a controlled growth experiment on three tree species showed that drought adaptation may results in plants with stronger and stiffer tissue. Our results indicate that hydraulic and mechanical stress adaptations may be interrelated, and so support recent studied suggesting that physiological responses are complex balances rather than pure optimisations. ©2008 Landes Bioscience.
Address University of Alberta, Department of Renewable Resources, 4-44 Earth Science Bldg., Edmonton, AB T6G 2E3, Canada
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 15592316 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 25 January 2012; Source: Scopus; Language of Original Document: English; Correspondence Address: Christensen-Dalsgaard, K. K.; University of Alberta, Department of Renewable Resources, 4-44 Earth Science Bldg., Edmonton, AB T6G 2E3, Canada; email: kkchrist@ualberta.ca Approved no
Call Number EcoFoG @ webmaster @ Serial 380
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Author Courtois, E.A.; Paine, C.E.T.; Blandinieres, P.A.; Stien, D.; Bessiere, J.M.; Houel, E.; Baraloto, C.; Chave, J.
Title Diversity of the Volatile Organic Compounds Emitted by 55 Species of Tropical Trees: a Survey in French Guiana Type Journal Article
Year (up) 2009 Publication Journal of Chemical Ecology Abbreviated Journal J. Chem. Ecol.
Volume 35 Issue 11 Pages 1349-1362
Keywords VOCs; Chemical diversity; Sesquiterpenes; Tropical; French Guiana
Abstract Volatile organic compounds (VOCs) are produced by a broad range of organisms, from bacteria to mammals, and they represent a vast chemical diversity. In plants, one of the preeminent roles of VOCs is their repellent or cytotoxic activity, which helps the plant deter its predators. Most studies on VOCs emitted by vegetative parts have been conducted in model plant species, and little is known about patterns of VOC emissions in diverse plant communities. We conducted a survey of the VOCs released immediately after mechanical damage of the bark and the leaves of 195 individual trees belonging to 55 tropical tree species in a lowland rainforest of French Guiana. We discovered a remarkably high chemical diversity, with 264 distinct VOCs and a mean of 37 compounds per species. Two monoterpenes (alpha-pinene and limonene) and two sesquiterpenes (beta-caryophyllene and alpha-copaene), which are known to have cytotoxic and deterrent effects, were the most frequent compounds in the sampled species. As has been established for floral scents, the blend of VOCs is largely species-specific and could be used to discriminate among 43 of the 55 sampled species. The species with the most diverse blends were found in the Sapindales, Laurales, and Magnoliales, indicating that VOC diversity is not uniformly distributed among tropical species. Interspecific variation in chemical diversity was caused mostly by variation in sesquiterpenes. This study emphasizes three aspects of VOC emission by tropical tree species: the species-specificity of the mixtures, the importance of sesquiterpenes, and the wide-ranging complexity of the mixtures.
Address [Courtois, Elodie A.; Blandinieres, Pierre-Alain; Stien, Didier; Houel, Emeline] CNRS, UMR Ecofog, F-97337 Cayenne, France, Email: courtois@cict.fr
Corporate Author Thesis
Publisher SPRINGER Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0098-0331 ISBN Medium
Area Expedition Conference
Notes ISI:000273086100009 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 73
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