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Lauth, J., Ruiz-González, M. X., & Orivel, J. (2011). New findings in insect fungiculture: Have ants developed non-food, agricultural products? Comm & Integr Biol, 4(1942-0889), 728–730.
Abstract: The interaction between Allomerus plant-ants and an ascomycete fungus growing on and strengthening their galleries is not opportunistic. We previously demonstrated that this association is highly specific as only one fungal species represented by a few haplotypes was found associated with the ants. We also discovered that the ants' behavior revealed a major investment in manipulating and enhancing the growth of their associated fungus. We have growing evidence that this specificity is consistent with selection by the ants. Here, we discuss this selection within the framework of insect agriculture, as we believe these ants fulfill all of the prerequisites to be considered as farmers. Allomerus ants promote their symbiont's growth, protect it from potential pathogens and select specific cultivars. Taken together, we think that the interaction between Allomerus ants and their cultivar might represent the first case of insect fungiculture used as a means of obtaining building material.
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Eva, H. D., Belward, A. S., De Miranda, E. E., Di Bella, C. M., Gond, V., Huber, O., et al. (2004). A land cover map of South America. Glob. Change Biol., 10(5), 731–744.
Abstract: A digital land cover map of South America has been produced using remotely sensed satellite data acquired between 1995 and the year 2000. The mapping scale is defined by the 1 km spatial resolution of the map grid-cell. In order to realize the product, different sources of satellite data were used, each source providing either a particular parameter of land cover characteristic required by the legend, or mapping a particular land cover class. The map legend is designed both to fit requirements for regional climate modelling and for studies on land cover change. The legend is also compatible with a wider, global, land cover mapping exercise, which seeks to characterize the world's land surface for the year 2000. As a first step, the humid forest domain has been validated using a sample of high-resolution satellite images. The map demonstrates both the major incursions of agriculture into the remaining forest domains and the extensive areas of agriculture, which now dominate South America's grasslands.
Keywords: Amazonia; ecosystems; land cover; mapping; South America; vegetation classes
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Fontaine, S., Stahl, C., Klumpp, K., Picon-Cochard, C., Grise, M. M., Dezécache, C., et al. (2018). Response to Editor to the comment by Schipper and Smith to our paper entitled 'Continuous soil carbon storage of old permanent pastures in Amazonia'. Global Change Biology, 24(3), e732–e733.
Keywords: chronosequence study; continuous C accumulation; deep soil C; eddy covariance; grassland
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Barassé, V., Touchard, A., Téné, N., Tindo, M., Kenne, M., Klopp, C., et al. (2019). The peptide venom composition of the fierce stinging ant tetraponera aethiops (formicidae: Pseudomyrmecinae). Toxins, 11(12), 732.
Abstract: In the mutualisms involving certain pseudomyrmicine ants and different myrmecophytes (i.e., plants sheltering colonies of specialized “plant-ant” species in hollow structures), the ant venom contributes to the host plant biotic defenses by inducing the rapid paralysis of defoliating insects and causing intense pain to browsing mammals. Using integrated transcriptomic and proteomic approaches, we identified the venom peptidome of the plant-ant Tetraponera aethiops (Pseudomyrmecinae). The transcriptomic analysis of its venom glands revealed that 40% of the expressed contigs encoded only seven peptide precursors related to the ant venom peptides from the A-superfamily. Among the 12 peptide masses detected by liquid chromatography-mass spectrometry (LC-MS), nine mature peptide sequences were characterized and confirmed through proteomic analysis. These venom peptides, called pseudomyrmecitoxins (PSDTX), share amino acid sequence identities with myrmeciitoxins known for their dual offensive and defensive functions on both insects and mammals. Furthermore, we demonstrated through reduction/alkylation of the crude venom that four PSDTXs were homo- and heterodimeric. Thus, we provide the first insights into the defensive venom composition of the ant genus Tetraponera indicative of a streamlined peptidome.
Keywords: Defensive venom; Dimeric peptides; Peptidome; Tetraponera aethiops
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Bremaud, I., Gril, J., & Thibaut, B. (2011). Anisotropy of wood vibrational properties: dependence on grain angle and review of literature data. Wood Sci. Technol., 45(4), 735–754.
Abstract: The anisotropy of vibrational properties influences the acoustic behaviour of wooden pieces and their dependence on grain angle (GA). As most pieces of wood include some GA, either for technological reasons or due to grain deviations inside trunks, predicting its repercussions would be useful. This paper aims at evaluating the variability in the anisotropy of wood vibrational properties and analysing resulting trends as a function of orientation. GA dependence is described by a model based on transformation formulas applied to complex compliances, and literature data on anisotropic vibrational properties are reviewed. Ranges of variability, as well as representative sets of viscoelastic anisotropic parameters, are defined for mean hardwoods and softwoods and for contrasted wood types. GA-dependence calculations are in close agreement with published experimental results and allow comparing the sensitivity of different woods to GA. Calculated trends in damping coefficient (tan delta) and in specific modulus of elasticity (E'/rho) allow reconstructing the general tan delta-E'/rho statistical relationships previously reported. Trends for woods with different mechanical parameters merge into a single curve if anisotropic ratios (both elastic and of damping) are correlated between them, and with axial properties, as is indicated by the collected data. On the other hand, varying damping coefficient independently results in parallel curves, which coincide with observations on chemically modified woods, either “artificially”, or by natural extractives.
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Lenoir, A., Devers, S., Touchard, A., & Dejean, A. (2016). The Guianese population of the fire ant Solenopsis saevissima is unicolonial. Insect Science, 23(5), 739–745.
Abstract: In this study, conducted in French Guiana, a part of the native range of the fire ant Solenopsis saevissima, we compared the cuticular hydrocarbon profiles of media workers with previous results based on intraspecific aggressiveness tests. We noted a strong congruence between the two studies permitting us to delimit 2 supercolonies extending over large distances (up to 54 km), a phenomenon known as unicoloniality. Solenopsis geminata workers, taken as an out-group for cluster analyses, have a very different cuticular hydrocarbon profile. Because S. saevissima has been reported outside its native range, our conclusion is that this species has the potential to become invasive because unicoloniality (i.e., the main attribute for ants to become invasive) was shown at least for the Guianese population. © 2015 Institute of Zoology, Chinese Academy of Sciences
Keywords: biological invasions; cuticular hydrocarbons; fire ants; unicoloniality
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Maia, A. C. D., Schlindwein, C., Navarro, D. M. A. F., & Gibernau, M. (2010). Pollination of Philodendron Acutatum (Araceae) in the Atlantic Forest of Northeastern Brazil: A Single Scarab Beetle Species Guarantees High Fruit Set. Int. J. Plant Sci., 171(7), 740–748.
Abstract: Philodendron acutatum (Araceae) is a hemiepiphyte common to the Atlantic Forest of northeastern Brazil. In two localities, we studied the species' breeding system and associations with flower-visiting insects, along with an analysis of its floral scent composition. The fruit set of self-incompatible P. acutatum was high, more than 90%, and inflorescences were exclusively pollinated by one species of scarab beetle, Cyclocephala celata (Scarabaeidae, Dynastinae). Pollinators are drawn toward the inflorescences at dusk by strong floral fragrances given off during the female phase of anthesis, along with endogenous heating of the spadix, whose temperatures were recorded at more than 11 degrees C above ambient air. Two other species of flower-visiting Cyclocephala were also consistently recovered in blacklight trappings during the flowering period of P. acutatum. The fact that only C. celata was found in association with P. acutatum suggests a local reproductive dependence of the plant to this scarab beetle species. Dihydro-beta-ionone and 2-hydroxy-5-methyl-3-hexanone, a rare volatile molecule so far unreported as a floral compound, together accounted for more than 97% of the unique scent composition of P. acutatum and might be involved in specific attraction of C. celata.
Keywords: Cyclocephala; floral volatiles; pollination specificity; reproductive success; thermogenesis
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Sprenger, P. P., Hartke, J., Feldmeyer, B., Orivel, J., Schmitt, T., & Menzel, F. (2019). Influence of Mutualistic Lifestyle, Mutualistic Partner, and Climate on Cuticular Hydrocarbon Profiles in Parabiotic Ants. J Chem Ecol, 45(9), 741–754.
Abstract: A vital trait in insects is their cuticular hydrocarbon (CHC) profile, which protects the insect against desiccation and serves in chemical communication. Due to these functions, CHC profiles are shaped by both climatic conditions and biotic interactions. Here, we investigated CHC differentiation in the neotropical parabiotic ant species Crematogaster levior and Camponotus femoratus, which mutualistically share a nest. Both consist of two cryptic species each (Cr. levior A and B and Ca. femoratus PAT and PS) that differ genetically and possess strongly different CHC profiles. We characterized and compared CHC profiles of the four cryptic species in detail. Our results suggest that Cr. levior A, Ca. femoratus PAT and Ca. femoratus PS adapted their CHC profiles to the parabiotic lifestyle by producing longer-chain CHCs. At the same time, they changed their major CHC classes, and produce more alkadienes and methyl-branched alkenes compared to Cr. levior B or non-parabiotic species. The CHC profiles of Cr. levior B were more similar to related, non-parabiotic species of the Orthocrema clade than Cr. levior A, and the chain lengths of B were similar to the reconstructed ancestral state. Signals of both the parabiotic partner (biotic conditions) and climate (abiotic conditions) were found in the CHC profiles of all four cryptic species. Our data suggest that mutualisms shaped the CHC profiles of the studied species, in particular chain length and CHC class composition. Beside this, signals of the parabiotic partners indicate potential impacts of biotic interactions, via chemical mimicry or chemical camouflage.
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Ghislain, B., Nicolini, E. - A., Romain, R., Ruelle, J., Yoshinaga, A., Alford, M. H., et al. (2016). Multilayered structure of tension wood cell walls in Salicaceae sensu lato and its taxonomic significance. Bot. J. Linn. Soc., 182(4), 744–756.
Abstract: Salicaceae have been enlarged to include a majority of the species formerly placed in the polyphyletic tropical Flacourtiaceae. Several studies have reported a peculiar and infrequently formed multilayered structure of tension wood in four of the tropical genera. Tension wood is a tissue produced by trees to restore their vertical orientation and most studies have focused on trees developing tension wood by means of cellulose-rich, gelatinous fibres, as in Populus and Salix (Salicaceae s.s.). This study aims to determine if the multilayered structure of tension wood is an anatomical characteristic common in other Salicaceae and, if so, how its distribution correlates to phylogenetic relationships. Therefore, we studied the tension wood of 14 genera of Salicaceae and two genera of Achariaceae, one genus of Goupiaceae and one genus of Lacistemataceae, families closely related to Salicaceae or formerly placed in Flacourtiaceae. Opposite wood and tension wood were compared with light microscopy and three-dimensional laser scanning confocal microscopy. The results indicate that a multilayered structure of tension wood is common in the family except in Salix, Populus and one of their closest relatives, Idesia polycarpa. We suggest that tension wood may be a useful anatomical character in understanding phylogenetic relationships in Salicaceae. Further investigation is still needed on the tension wood of several other putatively close relatives of Salix and Populus, in particular Bennettiodendron, Macrohasseltia and Itoa.
Keywords: Flacourtiaceae; G-layer; multilayered tension wood; reaction wood
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Dejean, A., Petitclerc, F., Azémar, F., & Rossi, V. (2021). Nutrient provisioning of its host myrmecophytic tree by a temporary social parasite of a plant-ant. Biological Journal of the Linnean Society, 133(3), 744–750.
Abstract: One of the most advanced ant–plant mutualisms is represented by myrmecophytes sheltering colonies of some plant-ant species in hollow structures called domatia. In turn, the myrmecophytes benefit from biotic protection and sometimes nutrient provisioning (myrmecotrophy). Furthermore, over the course of evolution, some ant species have become social parasites of others. In this general context, we studied the relationship between its host trees and Azteca andreae (Dolichoderinae), a temporary social parasite of the plant-ant Azteca ovaticeps, and, as such, obligatorily associated with myrmecophytic Cecropia obtusa trees (Urticaceae). A first experiment showed that the δ15N values of the young leaves of Cecropia sheltering a mature A. andreae colony were very similar to those for trees sheltering Azteca alfari or A. ovaticeps, two typical Cecropia mutualists for which myrmecotrophy is known. In a second experiment, by injecting a 15N-labelled glycine solution into locusts given as prey to A. andreae colonies, we triggered an increase in δ15N in the young leaves of their host Cecropia. Thus, 15N passed from the prey to the host trees, explaining the outcomes of the first experiment. We discuss these results in light of the notion of ‘by-product benefits’.
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