Questions Climate change is dramatically altering rainfall patterns and species distribution around the world. However, little is known about how rainfall reduction may affect plant–herbivore interactions that are crucial to the of input energy and nutrients into terrestrial ecosystems. Following Coley’s growth rate hypothesis, we assessed whether rainfall reduction in a seasonally dry tropical forest decreases community‐level herbivory owing to water shortage in drier areas. Location Catimbau National Park, Northeast Brazil. Methods We sampled 16 herb communities along a rainfall gradient (564–917 mm). Using digital photographs, we monitored for 3 weeks the frequency, magnitude and type (feeding guild) of insect damage on young, fully expanded, short‐lived leaves (lifespan <1 month). We related herbivory levels to local rainfall and examined potential confounding effects of herb abundance, richness and floristic composition on such relationships. Results We monitored 290 leaves from 202 plants belonging to 28 species. About one‐third of the leaves and six species escaped from herbivory. Leaf‐chewing insects were the most frequent herbivores, attacking 17 species, 44% ± 15% of the leaves and removing the same amount of foliar tissue as all the other insects combined removed (sap‐sucking, rasping, leaf‐mining and ‘unknown’). Contrary to expectations, foliar damage accumulated more in drier areas following the increase in the frequency of leaf‐chewing damage. In addition, frequency and magnitude of herbivory did not vary with herb abundance and richness and were weakly influenced by floristic composition. Conclusions Our findings suggest that rainfall underlies community‐level herbivory by mechanisms not related to plant availability, identity and diversity. Based on recent evidence that aridity favours leaf‐chewing proliferation in the study region, we hypothesize that rainfall reduction may weaken the top‐down control of herbivores, increasing folivory pressure on herbs. If prolonged droughts become more frequent in the coming decades, plant–herbivore interactions may be altered permanently.

BackgroundAdvancements in proteomics, including the technological improvement in instrumentation, have turned mass spectrometry into an indispensable tool in the study of venoms and toxins. In addition, the advance of nanoscale liquid chromatography coupled to nanoelectrospray mass spectrometry allows, due to its high sensitivity, the study of venoms from species previously left aside, such as ants. Ant venoms are a complex mixture of compounds used for defense, predation or communication purposes. The venom from Neoponera ants, a genus restricted to Neotropical regions, is known to have cytolytic, hemolytic, antimicrobial and insecticidal activities. Moreover, venoms from several Neoponera species have been compared and differences in their toxicity related to nesting habitat variation were reported. Therefore, the present study aimed to perform a deep peptidomic analysis of Neoponera villosa venom and a comparison of seasonal and nesting habitat variations using high-resolution mass spectrometry.MethodsSpecimens of N. villosa ants were captured in Panga Natural Reserve (Uberlândia, MG, Brazil) from arboreal and ground-dwelling nests during summer and winter time. The venom glands were dissected, pooled and disrupted by ultra-sonic waves. The venom collected from different habitats (arboreal and ground-dwelling) and different seasons (summer and winter) was injected into a nanoACQUITY ULPC hyphened to a Q-Exactive Orbitrap mass spectrometer. The raw data were analyzed using PEAKS 7.ResultsThe results showed a molecular diversity of more than 500 peptides among these venoms, mostly in the mass range of 800–4000 Da. Mutations and post-translational modifications were described and differences among the venoms were observed. Part of the peptides matched with ponericins, a well-known antimicrobial peptide family. In addition, smaller fragments related to ponericins were also identified, suggesting that this class of antimicrobial peptide might undergo enzymatic cleavages.ConclusionThere are substantial differences among the venom of N. villosa ants collected in different seasons and from different nest habitats. The venom composition is affected by climate changes that influence prey availability and predator presence. Clearly, nano-LC-MS boosted the knowledge about ant venom, a rich source of unexplored and promising bioactive compounds.Electronic supplementary materialThe online version of this article (10.1186/s40409-018-0141-3) contains supplementary material, which is available to authorized users.

Neotropical Entomology 33(3): 391-393 (2004) PALAVRAS-CHAVE: Especialização de microhabitats, herbivoria, limitação no forrageamento, Serra do CipóABSTRACT -Foraging rate can directly affect the impact that Atta laevigata (Smith) has on the environment. We attempted to assess the factors which most affect foraging rate of A. laevigata using data collected over a three month period in the Parque Nacional da Serra do Cipó in Minas Gerais, Brazil. A bimodal foraging pattern was observed on clear sunny days, based on collected dry weights of vegetative material being carried towards nest entrances. Sampled entrances on clear sunny days yielded a daily average dry weight twice as high (0.9713 ± 0.1358 g) as on rainy days (0.4485 ± 0.1120 g). Larger nests (0.9713 ± 0.1358 g) yielded higher dry weights than smaller nests (0.2752 ± 0.0463 g). Field observations showed Ants switched to nest entrances with more suitable microhabitat conditions in both rainy and sunny days. A combination of temperature, humidity, nest size, and microhabitat specialization were the most important factors influencing A. laevigata foraging pattern.

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