| Home | [1–10] << 11 12 13 14 15 16 17 18 19 20 >> [21–30] |
|
Martin, J. M., Roux, O., Groc, S., & Dejean, A. (2011). A type of unicoloniality within the native range of the fire ant Solenopsis saevissima. C. R. Biol., 334(4), 307–310.
Abstract: To determine if a type of unicoloniality exists in the fire ant Solenopsis saevissima in its native range, we conducted intraspecific aggressiveness tests in French Guiana between workers originating from 15 human-disturbed sites. We identified two “colonial groups” spread over 54 km and 12.5 km, respectively. Workers from the same group never attacked each other, but inter-group confrontations resulted in a high level of aggressiveness. These large “colonial groups” enhances the threat occasioned by S. saevissima for both agriculture and the environment. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Keywords: Ants; Solenopsis saevissima; Native range; Unicoloniality
|
|
Hattenschwiler, S., Fromin, N., & Barantal, S. (2011). Functional diversity of terrestrial microbial decomposers and their substrates. C. R. Biol., 334(5-6), 393–402.
Abstract: The relationship between biodiversity and biogeochemical processes gained much interest in light of the rapidly decreasing biodiversity worldwide. In this article, we discuss the current status, challenges and prospects of functional concepts to plant litter diversity and microbial decomposer diversity. We also evaluate whether these concepts permit a better understanding of how biodiversity is linked to litter decomposition as a key ecosystem process influencing carbon and nutrient cycles. Based on a literature survey, we show that plant litter and microbial diversity matters for decomposition, but that considering numbers of taxonomic units appears overall as little relevant and less useful than functional diversity. However, despite easily available functional litter traits and the well-established theoretical framework for functional litter diversity, the impact of functional litter diversity on decomposition is not yet well enough explored. Defining functional diversity of microorganisms remains one of the biggest challenges for functional approaches to microbial diversity. Recent developments in microarray and metagenomics technology offer promising possibilities in the assessment of the functional structure of microbial communities. This might allow significant progress in measuring functional microbial diversity and ultimately in our ability to predict consequences of biodiversity loss in the decomposer system for biogeochemical processes. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Keywords: Bacteria; Biogeochemical cycles; Decomposition; Dissimilarity; Ecosystem functioning; Functional diversity indices; Fungi; Leaf litter
|
|
Masse, P. S. M., Kenne, M., Mony, R., Dejean, A., & Tindo, M. (2011). Initial behavior in colony fragments of an introduced population of the invasive ant Wasmannia auropunctata. C. R. Biol., 334(7), 572–576.
Abstract: We investigated in the laboratory the initial behavior of propagules of the invasive ant Wasmannia auropunctata in Cameroon where it has been introduced. Both workers and queens at first feigned death (thanatosis), and then the workers slowly moved around the experimental arena; the queens did the same about 10 seconds later. Each queen antennated selected workers that then aggregated together by grasping the hind leg of another ant with their mandibles. When encountering the queen again, the lead worker climbed up the queen's hind leg and onto her back, followed by some other individuals. The remaining workers followed the queen to a location in the experimental arena. When brood was present, the workers transferred it to this location. Orphaned workers did not aggregate, but gathered the brood together and took care of it. By permitting propagules to survive, these behaviors likely contribute to the success of W. auropunctata as an invader. (C) 2011 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Keywords: Aggregation; Death feigning; Thanatosis; Worker transportation; Biological invasion; Little fire ant
|
|
Groc, S., Delabie, J. H. C., Cereghino, R., Orivel, J., Jaladeau, F., Grangier, J., et al. (2007). Ant species diversity in the 'Grands Causses' (Aveyron, France): In search of sampling methods adapted to temperate climates RID C-4034-2011. C. R. Biol., 330(12), 913–922.
Abstract: This study aimed at showing the applicability of using a combination of four sampling methods (i.e., Winkler extractors, pitfall traps, baiting and manual collection), something most often conducted in the tropics, to create an inventory of ant species diversity in temperate environments. We recorded a total of 33 ant species in the Grands Causses by comparing three vegetal formations: a steppic lawn ('causse' sensu stricto), which was the most species-rich (29 species), followed by an oak grove (22 species) and a pine forest (17 species). No sampling method alone is efficient enough to provide an adequate sampling, but their combination permits one to make a suitable inventory of the myrmecofauna and to obtain information on the ecology of these ant species.
Keywords: ant diversity; Grands Causses; sampling methods; temperate climate
|
|
Dejean, A., Compin, A., Leponce, M., Azémar, F., Bonhomme, C., Talaga, S., et al. (2018). Ants impact the composition of the aquatic macroinvertebrate communities of a myrmecophytic tank bromeliad. Comptes Rendus Biologies, 341(3), 200–207.
Abstract: In an inundated Mexican forest, 89 out of 92 myrmecophytic tank bromeliads (Aechmea bracteata) housed an associated ant colony: 13 sheltered Azteca serica, 43 Dolichoderus bispinosus, and 33 Neoponera villosa. Ant presence has a positive impact on the diversity of the aquatic macroinvertebrate communities (n=30 bromeliads studied). A Principal Component Analysis (PCA) showed that the presence and the species of ant are not correlated to bromeliad size, quantity of water, number of wells, filtered organic matter or incident radiation. The PCA and a generalized linear model showed that the presence of Azteca serica differed from the presence of the other two ant species or no ants in its effects on the aquatic invertebrate community (more predators). Therefore, both ant presence and species of ant affect the composition of the aquatic macroinvertebrate communities in the tanks of A. bracteata, likely due to ant deposition of feces and other waste in these tanks. Résumé Dans une forêt inondable du Mexique, sur 92 individus de la broméliacée myrmécophyte Aechmea bracteata, seuls trois étaient dépourvus d’une colonie de fourmis, 13 abritaient Azteca serica, 43 Dolichoderus bispinosus et 33 Neoponera villosa. La présence des fourmis favorise la diversité au sein des communautés aquatiques de macro-invertébrés (30 broméliacées étudiées, index de Shannon, profils de diversité). Une analyse en composantes principales (ACP) montre que la présence de fourmis n’est pas corrélée avec la taille de la plante, la quantité d’eau, le nombre de puits, la quantité de matière organique et la radiation incidente. L’ACP et un modèle mixte généralisé montrent un impact d’Azteca serica (comparé aux autres cas) attribuable à une plus grande quantité de prédateurs (effet top–down). La présence et l’identité des fourmis jouent un rôle sur la composition des communautés de macro-invertébrés aquatiques à travers des interactions directes, les ouvrières évacuant fèces et déchets dans les réservoirs.
Keywords: Aquatic macroinvertebrates; Ant-plant relationships; Diversity; Food webs; Tank bromeliads; Macro-invertébrés aquatiques; Relations plantes-fourmis; Diversité; Réseaux trophiques; Broméliacées à réservoirs
|
|
Hénaut, Y., Corbara, B., Azémar, F., Céréghino, R., Dézerald, O., & Dejean, A. (2018). An arboreal spider protects its offspring by diving into the water of tank bromeliads. Comptes Rendus Biologies, 341(3), 196–199.
Abstract: Cupiennius salei (Ctenidae) individuals frequently live in association with tank bromeliads, including Aechmea bracteata, in Quintana Roo (Mexico). Whereas C. salei females without egg sacs hunt over their entire host plant, females carrying egg sacs settle above the A. bracteata reservoirs they have partially sealed with silk. There they avoid predators that use sight to detect their prey, as is known for many bird species. Furthermore, if a danger is more acute, these females dive with their egg sacs into the bromeliad reservoir. An experiment showed that this is not the case for males or females without egg sacs. In addition to the likely abundance of prey found therein, the potential of diving into the tank to protect offspring may explain the close association of this spider with bromeliads. These results show that, although arboreal, C. salei evolved a protective behavior using the water of tank bromeliads to protect offspring. Résumé L’araignée Cupiennius salei (Ctenidae) vit souvent en association avec la broméliacée à réservoir Aechmea bracteata. Dans le Quintana Roo (Mexique), les femelles qui transportent un cocon s’installent au-dessus d’un réservoir d’A. bracteata qu’elles obstruent partiellement de voiles de soie pour se camoufler des prédateurs. En présence de vibrations importantes et répétées, ces femelles plongent avec leur cocon dans l’eau du réservoir. Notre étude montre que les autres adultes (mâles et femelles sans cocon) n’utilisent pas les réservoirs d’eau. Ainsi, en plus de l’abondance de proies, la possibilité de pouvoir plonger pour protéger la descendance pourrait expliquer l’association entre cette espèce d’araignée et les broméliacées. Nos expériences montrent que les femelles porteuses d’un cocon manifestent une stratégie de protection vis-à-vis des cocons et d’elles-mêmes en s’immergeant durant 30, voire 90minutes.
Keywords: Water used in protective behavior; Egg sacs; ; ; Cocons; Eau utilisée dans un comportement protecteur
|
|
Corbara, B., Servigne, P., Dejean, A., Carpenter, J. M., & Orivel, J. (2018). A mimetic nesting association between a timid social wasp and an aggressive arboreal ant. Comptes Rendus Biologies, 341(3), 182–188.
Abstract: In French Guiana, the arboreal nests of the swarm-founding social wasp Protopolybia emortualis (Polistinae) are generally found near those of the arboreal dolichoderine ant Dolichoderus bidens. These wasp nests are typically protected by an envelope, which in turn is covered by an additional carton ‘shelter’ with structure resembling the D. bidens nests. A few wasps constantly guard their nest to keep D. bidens workers from approaching. When alarmed by a strong disturbance, the ants invade the host tree foliage whereas the wasps retreat into their nest. Notably, there is no chemical convergence in the cuticular profiles of the wasps and ants sharing a tree. The aggressiveness of D. bidens likely protects the wasps from army ant raids, but the ants do not benefit from the presence of the wasps; therefore, this relationship corresponds to a kind of commensalism. Résumé En Guyane française, les nids de la guêpe Protopolybia emortualis (Polistinae) se trouvent généralement à proximité de ceux de la fourmi arboricole Dolichoderus bidens (Dolichoderinae). Ces nids de guêpes sont typiquement protégés par une enveloppe de carton, elle-même recouverte d’une autre enveloppe formant un abri qui ressemble aux nids de carton de D. bidens. Quelques guêpes gardent leur nid en permanence afin de tenir à distance les ouvrières D. bidens. Alarmées par une forte perturbation, les fourmis envahissent tout le feuillage de leur arbre support alors que les guêpes se réfugient dans leur nid. Il n’y a pas de convergence chimique entre les profils cuticulaires des guêpes et ceux des fourmis associées. Il est très probable que les P. emortualis bénéficient d’une protection contre les fourmis légionnaires grâce à l’agressivité des D. bidens, mais il n’y a pas réciprocité, de sorte que cette relation correspond à une forme de commensalisme.
Keywords: Ant-wasp interactions; ; ; Mimicry; Nest site selection; Relations guêpes-fourmis; ; ; Mimétisme; Sélection du site de nidification
|
|
Hamon, P., Duroy, P. - O., Dubreuil-Tranchant, C., Mafra D'Almeida Costa, P., Duret, C., Razafinarivo, N. J., et al. (2011). Two novel Ty1-copia retrotransposons isolated from coffee trees can effectively reveal evolutionary relationships in the Coffea genus (Rubiaceae). Mol. Genet. Genomics, 285(6), 447–460.
Abstract: In the study, we developed new markers for phylogenetic relationships and intraspecies differentiation in Coffea. Nana and Divo, two novel Ty1-copia LTR-retrotransposon families, were isolated through C. canephora BAC clone sequencing. Nana- and Divo-based markers were used to test their: (1) ability to resolve recent phylogenetic relationships; (2) efficiency in detecting intra-species differentiation. Sequence-specific amplification polymorphism (SSAP), retrotransposon-microsatellite amplified polymorphism (REMAP) and retrotransposon-based insertion polymorphism (RBIP) approaches were applied to 182 accessions (31 Coffea species and one Psilanthus accession). Nana- and Divo-based markers revealed contrasted transpositional histories. At the BAC clone locus, RBIP results on C. canephora demonstrated that Nana insertion took place prior to C. canephora differentiation, while Divo insertion occurred after differentiation. Combined SSAP and REMAP data showed that Nana could resolve Coffea lineages, while Divo was efficient at a lower taxonomic level. The combined results indicated that the retrotransposon-based markers were useful in highlighting Coffea genetic diversity and the chronological pattern of speciation/differentiation events. Ongoing complete sequencing of the C. canephora genome will soon enable exhaustive identification of LTR-RTN families, as well as more precise in-depth analyses on contributions to genome size variation and Coffea evolution. © 2011 Springer-Verlag.
Keywords: Coffea; Evolution; Genetic diversity; LTR-retrotransposons; article; coffee; controlled study; Divo; gene amplification; gene dosage; gene expression; gene insertion; gene locus; gene sequence; genetic identification; genetic polymorphism; genetic variability; molecular cloning; Nana; nonhuman; nucleotide sequence; phylogeny; plant evolution; plant gene; priority journal; Psilanthus; random amplified microsatellite; retroposon; Rubiaceae; species differentiation; tree; Ty1 copia gene; Coffea; Genes, Plant; Genome, Plant; Phylogeny; Retroelements
|
|
Porth, I., Scotti-Saintagne, C., Barreneche, T., Kremer, A., & Burg, K. (2005). Linkage mapping of osmotic stress induced genes of oak. Tree Genet. Genomes, 1(1), 31–40.
Abstract: Water stress affecting long-lived trees is an important challenge in forestry. Due to global climate change, forest trees will be threatened by extreme conditions like flooding or drought. It is necessary to understand differences in stress tolerance within certain species and to investigate putative relations on genomic level. In this study, osmotic stress induced genes of Quercus ssp. were positioned on two genetic linkage maps of oak. An intra-specific cross 3P*A4 of Quercus robur consisting of 88 offspring and an inter-specific cross 11P*QS29 of Q. robur and Q. petraea comprising 72 full-sibs were analyzed for the inheritance of 14 loci represented by 34 individual single nucleotide polymorphisms. Seven genes in the intra-cross, as well as other six genes in the inter-cross could be mapped and one gene could not be localised due to the severe distortion of the segregation. The collection of expressed sequences involved ribosomal proteins, members of the oxylase/oxygenase gene family, betaine aldehyde dehydrogenase, Dc3 promoter-binding factor, a putative member of the nodulin family, glutathione-S-transferase and proteins with unknown functions. In the inter-cross, two linked markers exhibited 89% deficiency of heterozygosity. Thirteen genes were positioned on ten different oak chromosomes and can serve as orthologous markers in comparative mapping studies within Fagaceae. © Springer-Verlag 2005.
Keywords: Est; Linkage map; Oak; Osmotic stress; Quercus ssp.; Fagaceae; Quercus; Quercus petraea; Quercus robur
|
|
Lenoir, A., Boulay, R., Dejean, A., Touchard, A., & Cuvillier-Hot, V. (2016). Phthalate pollution in an Amazonian rainforest. Environmental Science and Pollution Research, 23(16), 16865–16872.
Abstract: Phthalates are ubiquitous contaminants and endocrine-disrupting chemicals that can become trapped in the cuticles of insects, including ants which were recognized as good bioindicators for such pollution. Because phthalates have been noted in developed countries and because they also have been found in the Arctic, a region isolated from direct anthropogenic influence, we hypothesized that they are widespread. So, we looked for their presence on the cuticle of ants gathered from isolated areas of the Amazonian rainforest and along an anthropogenic gradient of pollution (rainforest vs. road sides vs. cities in French Guiana). Phthalate pollution (mainly di(2-ethylhexyl) phthalate (DEHP)) was higher on ants gathered in cities and along road sides than on those collected in the pristine rainforest, indicating that it follows a human-mediated gradient of disturbance related to the use of plastics and many other products that contain phthalates in urban zones. Their presence varied with the ant species; the cuticle of Solenopsis saevissima traps higher amount of phthalates than that of compared species. However, the presence of phthalates in isolated areas of pristine rainforests suggests that they are associated both with atmospheric particles and in gaseous form and are transported over long distances by wind, resulting in a worldwide diffusion. These findings suggest that there is no such thing as a “pristine” zone.
|