Abstract: Herbivory is viewed as a major driver of plant evolution and the most important energy pathway from plants to higher trophic levels. Therefore, understanding patterns of herbivory on plants remains a key focus in evolution and ecology. The evolutionary impacts of leaf herbivory include altering plant fitness, local adaptation, the evolution of defenses, and the diversification of plants as well as natural enemies. Leaf herbivory also impacts ecological processes such as plant productivity, community composition, and ecosystem nutrient cycling. Understanding the impact of herbivory on these ecological and evolutionary processes requires species-specific, as opposed to community-level, measures of herbivory. In addition, species-specific data enables the use of modern comparative methods to account for phylogenetic non-independence. Although hundreds of studies have measured natural rates of leaf consumption, we are unaware of any accessible compilation of these data. We created such a data set to provide the raw data needed to test general hypotheses relating to plant?herbivore interactions and to test the influence of biotic and abiotic factors on herbivory rates across large spatial scales. A large repository will make this endeavor more efficient and robust. In total, we compiled 2641 population-level measures for either annual or daily rates of leaf herbivory across 1145 species of vascular plants collected from 189 studies. All damage measures represent natural occurrences of herbivory that span numerous angiosperm, gymnosperm, and fern species. To enable researchers to explore the causes of variation in herbivory and how these might interact, we added information about the study sites including: geolocation, climate classification, habitat descriptions (e.g., seashore, grassland, forest, agricultural fields), and plant trait information concerning growth form and duration (e.g., annual vs. perennial). We also included extensive details of the methodology used to measure leaf damage, including seasons and months of sampling, age of leaves, and the method used to estimate percentage area missing. We anticipate that these data will make it possible to test important hypotheses in the plant?herbivore literature, including the plant apparency hypothesis, the latitudinal-herbivory defense hypothesis, the resource availability hypothesis, and the macroevolutionary escalation of defense hypothesis.

Abstract: Hylesia moths impact human health in South America, inducing epidemic outbreaks of lepidopterism, a puriginous dermatitis caused by the urticating properties of females' abdominal setae. The classification of the Hylesia genus is complex, owing to its high diversity in Amazonia, high intraspecific morphological variance, and lack of interspecific diagnostic traits which may hide cryptic species. Outbreaks of Hylesia metabus have been considered responsible for the intense outbreaks of lepidopterism in Venezuela and French Guiana since the C20, however, little is known about genetic variability throughout the species range, which is instrumental for establishing control strategies on H. metabus. Seven microsatellites and mitochondrial gene markers were analyzed from Hylesia moths collected from two major lepidopterism outbreak South American regions. The mitochondrial gene sequences contained significant genetic variation, revealing a single, widespread, polymorphic species with distinct clusters, possibly corresponding to populations evolving in isolation. The microsatellite markers validated the mitochondrial results, and suggest the presence of three populations: one in Venezuela, and two in French Guiana. All moths sampled during outbreak events in French Guiana were assigned to a single coastal population. The causes and implications of this finding require further research.

Abstract: Increasing or decreasing wood density (WD) from pith to bark is commonly observed in tropical tree species. The different types of WD radial variations, long been considered to depict the diversity of growth and mechanical strategies among forest guilds (heliophilic vs. shade-tolerant), were never analyzed in the light of heartwood (HW) formation. Yet, the additional mass of chemical extractives associated to HW formation increases WD and might affect both WD radial gradient (i.e., the slope of the relation between WD and radial distance) and pattern (i.e., linear or nonlinear variation). We studied 16 legumes species from French Guiana representing a wide diversity of growth strategies and positions on the shade-tolerance continuum. Using WD measurements and available HW extractives content values, we computed WD corrected by the extractive content and analyzed the effect of HW on WD radial gradients and patterns. We also related WD variations to demographic variables, such as sapling growth and mortality rates. Regardless of the position along the shade-tolerance continuum, correcting WD gradients reveals only increasing gradients. We determined three types of corrected WD patterns: (1) the upward curvilinear pattern is a specific feature of heliophilic species, whereas (2) the linear and (3) the downward curvilinear patterns are observed in both mid- and late-successional species. In addition, we found that saplings growth and mortality rates are better correlated with the corrected WD at stem center than with the uncorrected value: taking into account the effect of HW extractives on WD radial variations provides unbiased interpretation of biomass accumulation and tree mechanical strategies. Rather than a specific feature of heliophilic species, the increasing WD gradient is a shared strategy regardless of the shade tolerance habit. Finally, our study stresses to consider the occurrence of HW when using WD.

Abstract: In this study, the corrosion of S355 carbon steel was monitored for 50 days in equatorial environment. The experiments were conducted under three complementary approaches in a natural environment: (i) bacterial diversity was assessed with Miseq sequencing, (ii) observations of the surface and identifications of deposit compounds were realised with scanning electron microscopy (SEM), Raman spectrometry and EDX analyses, (iii) electrochemical measurements were used to calculate corrosion rate and to identify the phenomena which control corrosion. The results showed that the bacterial population had changed over immersion time from a dominance of β-proteobacteria to α-proteobacteria. This evolution decreased charge transfer resistance at the metal/deposit from 41.6 to 20.8 Ω/cm2 in 50 days, caused an increase in the corrosion rate by a factor of 2, from 0.13 to 0.27 mm/year. Surface analyses showed a progressive appearance of MIC markers in the deposit such as iron sulphide and manganese oxides that were detected after 30 days of immersion in the natural environment. In conclusion, this study describes in detail, the first stage of MIC activity on carbon steel surface in an equatorial brackish water, under aerobic conditions. © 2016 Elsevier Ltd.

Abstract: In the Neotropics where it was introduced, the invasive ant Pheidole megacephala counterattacked raids by the army ants Eciton burchellii or E. hamatum. The Eciton workers that returned to their bivouac were attacked and spread-eagled and most of them killed by their outgoing colony mates. Little by little the zone where returning and outgoing Eciton workers encountered one another moved away from the Pheidole nest which was no longer attacked, so that most of the colony was spared. Using a water-based technique rounded out by bioassays, we show that Pheidole compounds were transferred onto the Eciton cuticle during the counterattacks, so that outgoing workers do not recognize returning colony mates, likely perceived as potential prey. Because P. megacephala is an introduced African species, this kind of protection, which cannot be the result of coevolutive processes, corresponds to a kind of by-product due to its aggressiveness during colony defence. © 2014 Académie des sciences.