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Dezerald, O., Talaga, S., Leroy, C., Carrias, J. - F., Corbara, B., Dejean, A., et al. (2014). Environmental determinants of macroinvertebrate diversity in small water bodies: Insights from tank-bromeliads. Hydrobiologia, 723(1), 77–86.
Abstract: The interlocking leaves of tank-forming bromeliads (Bromeliaceae) collect rainwater and detritus, thus creating a freshwater habitat for specialized organisms. Their abundance and the possibility of quantifying communities with accuracy give us unparalleled insight into how changes in local to regional environments influence community diversity in small water bodies. We sampled 365 bromeliads (365 invertebrate communities) along a southeastern to northwestern range in French Guiana. Geographic locality determined the species pool for bromeliad invertebrates, and local environments determined the abundance patterns through the selection of traits that are best adapted to the bromeliad habitats. Patterns in community structure mostly emerged from patterns of predator species occurrence and abundance across local-regional environments, while the set of detritivores remained constant. Water volume had a strong positive correlation with invertebrate diversity, making it a biologically relevant measure of the pools' carrying capacity. The significant effects of incoming detritus and incident light show that changes in local environments (e.g., the conversion of forest to cropping systems) strongly influence freshwater communities. Because changes in local environments do not affect detritivores and predators equally, one may expect functional shifts as sets of invertebrates with particular traits are replaced or complemented by other sets with different traits. © 2013 Springer Science+Business Media Dordrecht.
Keywords: Freshwater biodiversity; Linear mixed effect modelling; Microcosms; Phytotelmata; Ponds
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Dutech, C., Seiter, J., Petronelli, P., Joly, H. I., & Jarne, P. (2002). Evidence of low gene flow in a neotropical clustered tree species in two rainforest stands of French Guiana. Mol. Ecol., 11(4), 725–738.
Abstract: The spatial genetic structure of the neotropical, clustered tree species Vouacapoua americana (Aublet) was studied in two natural forest stands (Paracou and Nouragues) in French Guiana. Using eight microsatellite loci, V. americana is characterized by a marked genetic structure at small spatial distances (under 30-60 m), in agreement with the limited seed dispersal by rodent species. Gene flow through pollen is also shown to be mainly restricted to less than 100 m. This result suggests that most pollination events (mediated through small insects) are probably limited to within-patches of individuals, which might explain the high genetic differentiation among patches (F-ST = 0.11) separated by less than 2 km. We also assume that stronger genetic structure in Paracou is likely to be due to lower seed dispersal by rodents, large spatial distances separating patches, or a recent recolonization event.
Keywords: Caesalpiniaceae; gene flow; recolonization process; spatial genetic structure; tropical rainforest; Vouacapoua americana
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Amusant, N., Nigg, M., Thibaut, B., & Beauchene, J. (2014). Diversity of decay resistance strategies of durable tropical woods species: Bocoa prouacencsis Aublet, Vouacapoua americana Aublet, Inga alba (Sw.) Wild. Int. Biodeterior. Biodegrad., 94, 103–108.
Abstract: The study of decay resistance in wood is of interest for wood end-users but also for the global carbon balance since wood biodegradation is a key driver of forest ecosystem functioning through its impacts on carbon and nutrient cycling. We studied the density and wood extractive contents in order to understand decay resistance against soil microflora after 90 days exposure of sapwood and heartwood from three Neotropical wood species known for their decay resistance: Bocoa prouacensis, Vouacapoua americana, Inga alba. Decay resistance was correlated with density more than wood extractive content. The results highlighted different decay resistance strategies. In B. prouacensis, both sapwood and heartwood were highly resistant due to the high density and high content of antifungal wood extractives. In V. americana heartwood, decay resistance was due to the high synergistic-acting wood extractive content. Conversely, with the least dense wood species I. alba, we found that decay resistance was due to the antifungal wood extractives synthesized early in the sapwood. In conclusion, we showed that the three wood species with the same level of heartwood decay resistance performance had different decay resistance strategies according to the anatomic and defensive wood traits.
Keywords: Decay resistance; Density; Heartwood; Sapwood; Tropical wood; Wood extractive; Decay resistance; Heartwood; Sapwood; Tropical wood; Wood extractives; Density (specific gravity); Andira aubletii; Bocoa; Inga
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Le Guen, R., Corbara, B., Rossi, V., Azémar, F., & Dejean, A. (2015). Reciprocal protection from natural enemies in an ant-wasp association. Comptes Rendus – Biologies, 338(4), 255–259.
Abstract: Abstract We show that in French Guiana the large carton nests of Azteca chartifex, a territorially-dominant arboreal dolichoderine ant, are protected from bird attacks when this ant lives in association with Polybia rejecta, an epiponine social wasp. Because A. chartifex colonies are well known for their ability to divert army ant raids from the base of their host tree so that they protect their associated wasps from these raids, there is a reciprocal benefit for these two partners, permitting us to call this association a mutualism. We also show that P. rejecta nests are significantly less often attacked by birds than are those of two compared epiponine social wasp species. Furthermore, experimentation using a standardized protocol demonstrated the significantly higher aggressiveness of P. rejecta compared to seven other wasp species. We conclude that the efficacious protection of its associated ant nests is likely due to the extreme aggressiveness of P. rejecta. © 2015 Académie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Keywords: Aggressiveness; Arboreal ants; Azteca; Polybia; Protection mutualism; Social wasps
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Stien, D., & Gastaldi, S. (2004). Design of polyaromatic hydrocarbon-supported tin reagents: A new family of tin reagents easily removable from reaction mixtures. J. Org. Chem., 69(13), 4464–4470.
Abstract: We report in this paper the preparation and use of stannanes 11, 12a, and 12b, compounds whose 3-pyrenylpropyl side chain affinity for activated carbon simplifies tin removal and product isolation. Our pyrene-supported reagents can be used for radical reductions and cyclizations (11), radical and cationic allylations (12a), and Stille couplings (12b) in much the same way as tributyltin derivatives.
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Casella, T. M., Eparvier, V., Mandavid, H., Bendelac, A., Odonne, G., Dayan, L., et al. (2013). Antimicrobial and cytotoxic secondary metabolites from tropical leaf endophytes: Isolation of antibacterial agent pyrrocidine C from Lewia infectoria SNB-GTC2402. Phytochemistry, 96, 370–377.
Abstract: Because of the symbiotic nature of endophytes, this survey aims to investigate the probability of discovering antibacterial, antifungal and cytotoxic activities in leaf endophytic microbes. We isolated 138 cultivable microbes (121 fungi, 3 bacteria and 14 unidentified or unknown microbes) from 24 plant species, a significant relative proportion of which exhibited antifungal and cytotoxic potential against Candida albicans ATCC 10213 and the human cell lines KB (uterine cervical carcinoma), MDA-MB-435 (melanoma), and MRC5 (normal human lung fibroblasts). Three active fungal extracts were fractionated, resulting in the isolation of eight compounds. Seven had been described in the literature including the following: acremonisol A, semicochliodinol A, cochliodinol, griseofulvin, pyrenocin A, novae zelandin A and alterperylenol. A previously unreported compound named pyrrocidine C was isolated from Lewia infectoria SNB-GTC2402 and identified by spectroscopic analysis. As in pyrrocidines A and B, this compound is a cis-substituted decahydrofluorene with a quaternary carbon at C-5 and opposite stereochemistry at C-8 corresponding to C-6 of pyrrocidines A and B.© 2013 Elsevier Ltd. All rights reserved.
Keywords: Antimicrobials; Cytotoxic metabolites; Functional chemodiversity; Leaf endophytes; Lewia; Pyrrocidine C
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LaPierre, L., Hespenheide, H., & Dejean, A. (2007). Wasps robbing food from ants: a frequent behavior? Naturwissenschaften, 94(12), 997–1001.
Abstract: Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes. (1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more common than previously thought.
Keywords: cleptobiosis; social wasps; charterginus; polybioides; plant-ants
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Talaga, S., Delabie, J. H. C., Dezerald, O., Salas-Lopez, A., Petitclerc, F., Leroy, C., et al. (2015). A bromeliad species reveals invasive ant presence in urban areas of French Guiana. Ecological Indicators, 58, 1–7.
Abstract: Tank bromeliads, frequently associated with ants, are considered 'biodiversity amplifiers' for both aquatic and terrestrial organisms, and thus have a high ecological value. The focal species of this study, Aechmea aquilega, sheltered the colonies of 12 ant species in a Guianese rural habitat where Odontomachus haematodus, associated with 60% of these plants, was the most frequent. Unexpectedly, the ant species richness was higher in a compared urban habitat with 21 species, but two synanthropic and four invasive ants were noted among them. Consequently, we conducted baiting surveys (on the ground, on trees and on trees bearing A. aquilega) as well as complementary surveys using different sampling modes in urban areas to test if A. aquilega is a surrogate revealing the presence of certain invasive ants. During the baiting survey, we recorded four Neotropical and eight introduced invasive ants out of a total of 69 species. Of these 12 invasive species, five were noted by baiting A. aquilega (including two only noted in this way). A bootstrap simulation permitted us to conclude that A. aquilega significantly concentrates certain species of invasive ants. This was confirmed by complementary surveys, where we did not record further species. We conclude that baiting on trees bearing large epiphytes in human-modified, Neotropical areas is a relevant complement to the early detection of invasive ants. © 2015 Elsevier Ltd. All rights reserved.
Keywords: Aechmea aquilega; Bioindicators; Non-specific ant-plant relationships; Surrogacy; Tank bromeliads; Urban ecology
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Coste, S., Roggy, J. C., Imbert, P., Born, C., Bonal, D., & Dreyer, E. (2005). Leaf photosynthetic traits of 14 tropical rain forest species in relation to leaf nitrogen concentration and shade tolerance. Tree Physiol., 25(9), 1127–1137.
Abstract: Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO2 assimilation rate versus intercellular CO2 mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen (N) and carbon (C) concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf N and C concentrations. No correlation was found between leaf thickness and density. The correlations between area- and mass-based leaf N concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relative N allocation to carboxylation and bioenergetics. Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leaf N invested in photosynthesis was tightly correlated to photosynthetic capacity. We also used PCA to test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA. We conclude that the large interspecific diversity in photosynthetic capacity was mostly explained by differences in the relative allocation of N to photosynthesis and not by leaf N concentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.
Keywords: functional diversity; leaf carbon; leaf nitrogen; nitrogen-use efficiency; photosynthetic capacity; tropical rain forest
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Faucheux, M. J., & Gibernau, M. (2011). Antennal sensilla in five Psychodini moth flies (Diptera: Psychodidae: Psychodinae) pollinators of Arum spp. (Araceae). Ann. Soc. Entomol. Fr., 47(1-2), 89–100.
Abstract: The pollination of the genus Arum (Araceae) is mainly achieved by deception, the floral odour mimicking the pollinator ovipositing site. In order to discover the sensory organs involved in this attraction, we have studied the antennae of five species of psychodine moth-flies (former Psychoda sensu lato = Psychodini), pollinators of Arum spp. The antennae of the five Psychodini reveal seven types of sensilla: multiporous tribranched sensilla basiconica (sensilla ascoidea), multiporous sensilla basiconica, multiporous sensilla coeloconica, multiporous sensilla auricillica, uniporous sensilla basiconica, aporous sensilla chaetica, aporous Böhm's sensilla. Each species possesses three, five or six of these sensillum types. All the multiporous sensilla are probably olfactory receptors while the uniporous sensilla basiconica must possess a contact chemoreceptive function. The multiporous tribranched sensilla basiconica (s. ascoidea), present in all the species, are the best candidates for the reception of the odours given off by the ovipositing sites and the inflorescences of Arum. The multiporous sensilla basiconica and the multiporous sensilla coeloconica may be involved respectively as CO2 receptors or thermoreceptors. Psychoda phalaenoides, which is the main pollinator of A. maculatum, is the species which possesses the largest number of antennal sensilla. The sexual dimorphism, studied only in Psycha grisescens, as concerns the number of sensilla and the absence of a sensillum type which differ according to sex, is difficult to interpret.
Keywords: Chodopsycha; Deceptive pollination; Logima; Psycha; Psychoda
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