|   | 
Details
   web
Records
Author Dejean, A.; Fisher, B.L.; Corbara, B.; Rarevohitra, R.; Randrianaivo, R.; Rajemison, B.; Leponce, M.
Title Spatial Distribution of Dominant Arboreal Ants in a Malagasy Coastal Rainforest: Gaps and Presence of an Invasive Species Type Journal Article
Year 2010 Publication PLoS One Abbreviated Journal PLoS One
Volume 5 Issue 2 Pages e9319
Keywords
Abstract We conducted a survey along three belt transects located at increasing distances from the coast to determine whether a non-random arboreal ant assemblage, such as an ant mosaic, exists in the rainforest on the Masoala Peninsula, Madagascar. In most tropical rainforests, very populous colonies of territorially dominant arboreal ant species defend absolute territories distributed in a mosaic pattern. Among the 29 ant species recorded, only nine had colonies large enough to be considered potentially territorially dominant; the remaining species had smaller colonies and were considered non-dominant. Nevertheless, the null-model analyses used to examine the spatial structure of their assemblages did not reveal the existence of an ant mosaic. Inland, up to 44% of the trees were devoid of dominant arboreal ants, something not reported in other studies. While two Crematogaster species were not associated with one another, Brachymyrmex cordemoyi was positively associated with Technomyrmex albipes, which is considered an invasive species-a non-indigenous species that has an adverse ecological effect on the habitats it invades. The latter two species and Crematogaster ranavalonae were mutually exclusive. On the other hand, all of the trees in the coastal transect and at least 4 km of coast were occupied by T. albipes, and were interconnected by columns of workers. Technomyrmex albipes workers collected from different trees did not attack each other during confrontation tests, indicating that this species has formed a supercolony along the coast. Yet interspecific aggressiveness did occur between T. albipes and Crematogaster ranavalonae, a native species which is likely territorially dominant based on our intraspecific confrontation tests. These results suggest that the Masoala rainforest is threatened by a potential invasion by T. albipes, and that the penetration of this species further inland might be facilitated by the low density of native, territorially dominant arboreal ants normally able to limit its progression.
Address [Dejean, Alain] CNRS, Unite Mixte Rech 8172, Kourou, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher (down) PUBLIC LIBRARY SCIENCE Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000274923700021 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 81
Permanent link to this record
 

 
Author Roux, O.; Billen, J.; Orivel, J.; Dejean, A.
Title An Overlooked Mandibular-Rubbing Behavior Used during Recruitment by the African Weaver Ant, Oecophylla longinoda Type Journal Article
Year 2010 Publication PLoS One Abbreviated Journal PLoS One
Volume 5 Issue 2 Pages e8957
Keywords
Abstract In Oecophylla, an ant genus comprising two territorially dominant arboreal species, workers are known to (1) use anal spots to mark their territories, (2) drag their gaster along the substrate to deposit short-range recruitment trails, and (3) drag the extruded rectal gland along the substrate to deposit the trails used in long-range recruitment. Here we study an overlooked but important marking behavior in which O. longinoda workers first rub the underside of their mandibles onto the substrate, and then-in a surprising posture-tilt their head and also rub the upper side of their mandibles. We demonstrate that this behavior is used to recruit nestmates. Its frequency varies with the rate at which a new territory, a sugary food source, a prey item, or an alien ant are discovered. Microscopy analyses showed that both the upper side and the underside of the mandibles possess pores linked to secretory glands. So, by rubbing their mandibles onto the substrate, the workers probably spread a secretion from these glands that is involved in nestmate recruitment.
Address [Roux, Olivier; Dejean, Alain] CNRS, UMR, Kourou, France, Email: oroux@cict.fr
Corporate Author Thesis
Publisher (down) PUBLIC LIBRARY SCIENCE Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000274209700003 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 82
Permanent link to this record
 

 
Author Gonzalez, M.A.; Baraloto, C.; Engel, J.; Mori, S.A.; Petronelli, P.; Riera, B.; Roger, A.; Thebaud, C.; Chave, J.
Title Identification of Amazonian Trees with DNA Barcodes Type Journal Article
Year 2009 Publication PLoS One Abbreviated Journal PLoS One
Volume 4 Issue 10 Pages e7483
Keywords
Abstract Background: Large-scale plant diversity inventories are critical to develop informed conservation strategies. However, the workload required for classic taxonomic surveys remains high and is particularly problematic for megadiverse tropical forests. Methodology/Principal Findings: Based on a comprehensive census of all trees in two hectares of a tropical forest in French Guiana, we examined whether plant DNA barcoding could contribute to increasing the quality and the pace of tropical plant biodiversity surveys. Of the eight plant DNA markers we tested (rbcLa, rpoC1, rpoB, matK, ycf5, trnL, psbA-trnH, ITS), matK and ITS had a low rate of sequencing success. More critically, none of the plastid markers achieved a rate of correct plant identification greater than 70%, either alone or combined. The performance of all barcoding markers was noticeably low in few species-rich clades, such as the Laureae, and the Sapotaceae. A field test of the approach enabled us to detect 130 molecular operational taxonomic units in a sample of 252 juvenile trees. Including molecular markers increased the identification rate of juveniles from 72% (morphology alone) to 96% (morphology and molecular) of the individuals assigned to a known tree taxon. Conclusion/Significance: We conclude that while DNA barcoding is an invaluable tool for detecting errors in identifications and for identifying plants at juvenile stages, its limited ability to identify collections will constrain the practical implementation of DNA-based tropical plant biodiversity programs.
Address
Corporate Author Thesis
Publisher (down) PUBLIC LIBRARY SCIENCE Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000270880700009 Approved no
Call Number EcoFoG @ eric.marcon @ Serial 189
Permanent link to this record
 

 
Author Dejean, A.; Corbara, B.; Leroy, C.; Delabie, J.H.C.; Rossi, V.; Cereghino, R.
Title Inherited Biotic Protection in a Neotropical Pioneer Plant Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS One
Volume 6 Issue 3 Pages e18071
Keywords
Abstract Chelonanthus alatus is a bat-pollinated, pioneer Gentianaceae that clusters in patches where still-standing, dried-out stems are interspersed among live individuals. Flowers bear circum-floral nectaries (CFNs) that are attractive to ants, and seed dispersal is both barochorous and anemochorous. Although, in this study, live individuals never sheltered ant colonies, dried-out hollow stems – that can remain standing for 2 years – did. Workers from species nesting in dried-out stems as well as from ground-nesting species exploited the CFNs of live C. alatus individuals in the same patches during the daytime, but were absent at night (when bat pollination occurs) on 60.5% of the plants. By visiting the CFNs, the ants indirectly protect the flowers – but not the plant foliage – from herbivorous insects. We show that this protection is provided mostly by species nesting in dried-out stems, predominantly Pseudomyrmex gracilis. That dried-out stems remain standing for years and are regularly replaced results in an opportunistic, but stable association where colonies are sheltered by one generation of dead C. alatus while the live individuals nearby, belonging to the next generation, provide them with nectar; in turn, the ants protect their flowers from herbivores. We suggest that the investment in wood by C. alatus individuals permitting still-standing, dried-out stems to shelter ant colonies constitutes an extended phenotype because foraging workers protect the flowers of live individuals in the same patch. Also, through this process these dried-out stems indirectly favor the reproduction (and so the fitness) of the next generation including both their own offspring and that of their siblings, all adding up to a potential case of inclusive fitness in plants.
Address [Dejean, Alain; Leroy, Celine] CNRS, Ecol Forets Guyane UMR CNRS 8172, Kourou, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher (down) Public Library Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000289057200023 Approved no
Call Number EcoFoG @ webmaster @ Serial 306
Permanent link to this record
 

 
Author Dejean, A.
Title Prey Capture Behavior in an Arboreal African Ponerine Ant Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS One
Volume 6 Issue 5 Pages e19837
Keywords
Abstract I studied the predatory behavior of Platythyrea conradti, an arboreal ponerine ant, whereas most species in this subfamily are ground-dwelling. The workers, which hunt solitarily only around dusk, are able to capture a wide range of prey, including termites and agile, nocturnal insects as well as diurnal insects that are inactive at that moment of the Nyctemeron, resting on tree branches or under leaves. Prey are captured very rapidly, and the antennal palpation used by ground-dwelling ponerine species is reduced to a simple contact; stinging occurs immediately thereafter. The venom has an instant, violent effect as even large prey (up to 30 times the weight of a worker) never struggled after being stung. Only small prey are not stung. Workers retrieve their prey, even large items, singly. To capture termite workers and soldiers defending their nest entrances, ant workers crouch and fold their antennae backward. In their role as guards, the termites face the crouching ants and end up by rolling onto their backs, their legs batting the air. This is likely due to volatile secretions produced by the ants' mandibular gland. The same behavior is used against competing ants, including territorially-dominant arboreal species that retreat further and further away, so that the P. conradti finally drive them from large, sugary food sources.
Address [Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: alain.dejean@wanadoo.fr
Corporate Author Thesis
Publisher (down) Public Library Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000290483600033 Approved no
Call Number EcoFoG @ webmaster @ Serial 316
Permanent link to this record
 

 
Author Brouard, O.; Le Jeune, A.H.; Leroy, C.; Cereghino, R.; Roux, O.; Pelozuelo, L.; Dejean, A.; Corbara, B.; Carrias, J.F.
Title Are Algae Relevant to the Detritus-Based Food Web in Tank-Bromeliads? Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS One
Volume 6 Issue 5 Pages e20129
Keywords
Abstract We assessed the occurrence of algae in five species of tank-bromeliads found in contrasting environmental sites in a Neotropical, primary rainforest around the Nouragues Research Station, French Guiana. The distributions of both algal abundance and biomass were examined based on physical parameters, the morphological characteristics of bromeliad species and with regard to the structure of other aquatic microbial communities held in the tanks. Algae were retrieved in all of the bromeliad species with mean densities ranging from similar to 10(2) to 10(4) cells/mL. Their biomass was positively correlated to light exposure and bacterial biomass. Algae represented a tiny component of the detrital food web in shaded bromeliads but accounted for up to 30 percent of the living microbial carbon in the tanks of Catopsis berteroniana, located in a highly exposed area. Thus, while nutrient supplies are believed to originate from wind-borne particles and trapped insects (i.e., allochtonous organic matter), our results indicate that primary producers (i.e., autochtonous organic matter) are present in this insectivorous bromeliad. Using a 24-h incubation of size-fractionated and manipulated samples from this plant, we evaluated the impact of mosquito foraging on algae, other microorganisms and rotifers. The prey assemblages were greatly altered by the predation of mosquito larvae. Grazing losses indicated that the dominant algal taxon, Bumilleriopsis sp., like protozoa and rotifers, is a significant part of the diet of mosquito larvae. We conclude that algae are a relevant functional community of the aquatic food web in C. berteroniana and might form the basis of a complementary non-detrital food web.
Address [Brouard, Olivier; Le Jeune, Anne-Helene; Corbara, Bruno; Carrias, Jean-Francois] Univ Clermont Ferrand, CNRS, Lab Microorganismes Genome & Environm, LMGE,UMR 6023, Aubiere, France, Email: j-francois.carrias@univ-bpclermont.fr
Corporate Author Thesis
Publisher (down) Public Library Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000290720200066 Approved no
Call Number EcoFoG @ webmaster @ Serial 319
Permanent link to this record
 

 
Author Roux, O.; Cereghino, R.; Solano, P.J.; Dejean, A.
Title Caterpillars and Fungal Pathogens: Two Co-Occurring Parasites of an Ant-Plant Mutualism Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS One
Volume 6 Issue 5 Pages e20538
Keywords
Abstract In mutualisms, each interacting species obtains resources from its partner that it would obtain less efficiently if alone, and so derives a net fitness benefit. In exchange for shelter (domatia) and food, mutualistic plant-ants protect their host myrmecophytes from herbivores, encroaching vines and fungal pathogens. Although selective filters enable myrmecophytes to host those ant species most favorable to their fitness, some insects can by-pass these filters, exploiting the rewards supplied whilst providing nothing in return. This is the case in French Guiana for Cecropia obtusa (Cecropiaceae) as Pseudocabima guianalis caterpillars (Lepidoptera, Pyralidae) can colonize saplings before the installation of their mutualistic Azteca ants. The caterpillars shelter in the domatia and feed on food bodies (FBs) whose production increases as a result. They delay colonization by ants by weaving a silk shield above the youngest trichilium, where the FBs are produced, blocking access to them. This probable temporal priority effect also allows female moths to lay new eggs on trees that already shelter caterpillars, and so to occupy the niche longer and exploit Cecropia resources before colonization by ants. However, once incipient ant colonies are able to develop, they prevent further colonization by the caterpillars. Although no higher herbivory rates were noted, these caterpillars are ineffective in protecting their host trees from a pathogenic fungus, Fusarium moniliforme (Deuteromycetes), that develops on the trichilium in the absence of mutualistic ants. Therefore, the Cecropia treelets can be parasitized by two often overlooked species: the caterpillars that shelter in the domatia and feed on FBs, delaying colonization by mutualistic ants, and the fungal pathogen that develops on old trichilia. The cost of greater FB production plus the presence of the pathogenic fungus likely affect tree growth.
Address [Roux, Olivier; Dejean, Alain] CNRS, Ecol Forets Guyane UMR 8172, Kourou, France, Email: olivier.roux@ird.fr
Corporate Author Thesis
Publisher (down) Public Library Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes ISI:000291097600091 Approved no
Call Number EcoFoG @ webmaster @ Serial 322
Permanent link to this record
 

 
Author Rifflet, A.; Tene, N.; Orivel, J.; Treilhou, M.; Dejean, A.; Vetillard, A.
Title Paralyzing Action from a Distance in an Arboreal African Ant Species Type Journal Article
Year 2011 Publication PLoS One Abbreviated Journal PLoS ONE
Volume 6 Issue 12 Pages e28571
Keywords
Abstract Due to their prowess in interspecific competition and ability to catch a wide range of arthropod prey (mostly termites with which they are engaged in an evolutionary arms race), ants are recognized as a good model for studying the chemicals involved in defensive and predatory behaviors. Ants' wide diversity of nesting habits and relationships with plants and prey types implies that these chemicals are also very diverse. Using the African myrmicine ant Crematogaster striatula as our focal species, we adopted a three-pronged research approach. We studied the aggressive and predatory behaviors of the ant workers, conducted bioassays on the effect of their Dufour gland contents on termites, and analyzed these contents. (1) The workers defend themselves or eliminate termites by orienting their abdominal tip toward the opponent, stinger protruded. The chemicals emitted, apparently volatile, trigger the recruitment of nestmates situated in the vicinity and act without the stinger having to come into direct contact with the opponent. Whereas alien ants competing with C. striatula for sugary food sources are repelled by this behavior and retreat further and further away, termites defend their nest whatever the danger. They face down C. striatula workers and end up by rolling onto their backs, their legs batting the air. (2) The bioassays showed that the toxicity of the Dufour gland contents acts in a time-dependent manner, leading to the irreversible paralysis, and, ultimately, death of the termites. (3) Gas chromatography-mass spectrometry analyses showed that the Dufour gland contains a mixture of mono- or polyunsaturated long-chain derivatives, bearing functional groups like oxo-alcohols or oxo-acetates. Electrospray ionization-mass spectrometry showed the presence of a molecule of 1584 Da that might be a large, acetylated alkaloid capable of splitting into smaller molecules that could be responsible for the final degree of venom toxicity.
Address
Corporate Author Thesis
Publisher (down) Public Library of Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number EcoFoG @ webmaster @ Serial 376
Permanent link to this record
 

 
Author Marcon, E.; Scotti, I.; Herault, B.; Rossi, V.; Lang, G.
Title Generalization of the partitioning of Shannon diversity Type Journal Article
Year 2014 Publication PLoS ONE Abbreviated Journal PLoS ONE
Volume 9 Issue 3 Pages e90289
Keywords
Abstract Traditional measures of diversity, namely the number of species as well as Simpson's and Shannon's indices, are particular cases of Tsallis entropy. Entropy decomposition, i.e. decomposing gamma entropy into alpha and beta components, has been previously derived in the literature. We propose a generalization of the additive decomposition of Shannon entropy applied to Tsallis entropy. We obtain a self-contained definition of beta entropy as the information gain brought by the knowledge of each community composition. We propose a correction of the estimation bias allowing to estimate alpha, beta and gamma entropy from the data and eventually convert them into true diversity. We advocate additive decomposition in complement of multiplicative partitioning to allow robust estimation of biodiversity. © 2014 Marcon et al.
Address INRA, UMR 518 Math. Info. Appli, Paris, France
Corporate Author Thesis
Publisher (down) Public Library of Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 19326203 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 18 April 2014; Source: Scopus; Art. No.: e90289; Coden: Polnc; Language of Original Document: English Approved no
Call Number EcoFoG @ webmaster @ Serial 538
Permanent link to this record
 

 
Author Wagner, F.; Rossi, V.; Aubry-Kientz, M.; Bonal, D.; Dalitz, H.; Gliniars, R.; Stahl, C.; Trabucco, A.; Herault, B.
Title Pan-tropical analysis of climate effects on seasonal tree growth Type Journal Article
Year 2014 Publication PLoS ONE Abbreviated Journal PLoS ONE
Volume 9 Issue 3 Pages e92337
Keywords
Abstract Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent. © 2014 Wagner et al.
Address Division of Forest, Nature, and Landscape, KU Leuven, Leuven, Belgium
Corporate Author Thesis
Publisher (down) Public Library of Science Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 19326203 (Issn) ISBN Medium
Area Expedition Conference
Notes Export Date: 30 May 2014; Source: Scopus; Art. No.: e92337; Coden: Polnc; Language of Original Document: English Approved no
Call Number EcoFoG @ webmaster @ Serial 543
Permanent link to this record