Succession and management of tropical dry forests in the Americas: Review and new perspectives

Understanding tropical forest succession is critical for the development of tropical forest conservation strategies worldwide, given that tropical secondary forests can be considered the forests of the future. Tropical dry forests (TDF) are among the most threatened tropical ecosystems, there are more secondary forests and forest restoration efforts that require a better understanding of successional processes. The main goal of this synthesis for this special issue on the ecology and management of tropical dry forests in the Americas is to present a summarized review of the current knowledge of the ecology and management implications associated to TDF succession. We explore specific issues associated to tropical dry forest succession with emphasis on the use of chronosequences, plant diversity and composition, plant phenology and remote sensing, pollination, and animal-plant interactions; all under the integrating umbrella of ecosystem succession. We also emphasize the need to conduct socio-ecological research to understand changes in land-use history and its effects on succession and forest regeneration of TDF. We close this paper with some thoughts and ideas associated with the strong need for an integrating dimension not considered until today: the role of cyberinfrastructure and eco-informatics as a tool to support sound conservation, management and understanding of TDF in the Americas. (C) 2009 Elsevier B.V. All rights reserved.

Effect of the insect growth regulator diflubenzuron on the predator Podisus nigrispinus (Heteroptera: Pentatomidae)

Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a common natural predator of defoliating caterpillars in agricultural and forest systems. Insecticides acting as growth regulators of insect pests can indirectly affect their predators through consumption of contaminated prey. We examined the reproductive performance of P. nigrispinus fed on caterpillars of Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae) reared on soybean leaves exposed to the chitin synthesis inhibitor, diflubenzuron. Caterpillars of A. gemmatalis were fed for 12 h with treated soybean leaves and offered to adults of the predator P. nigrispinus over five consecutive days. The fertility of P. nigrispinus was reduced when feeding on diflubenzuron treated caterpillars, especially at the beginning of the reproductive period, but recovered 3 weeks later. The effects of diflubenzuron ingestion on the life table parameters of P. nigrispinus included an increase in the period taken to double the population size, and reductions in the intrinsic rate of population increase, generation duration, and net reproductive rate. Diflubenzuron therefore had an indirect negative effect on the reproduction and the population dynamics of the non-target predator P. nigrispinus. Clearly, its use in integrated pest management requires further evaluation.

A stratigraphic chart of the Late Carboniferous/Permian succession of the eastern border of the Parana Basin, Brazil, South America

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

An exploratory insect survey of tropical soda apple in Brazil and Paraguay

An exploratory survey was conducted in Brazil and Paraguay to record insects feeding on Solanum viarum Dunal (Solanaceae). A list of insects collected is included. The survey indicated that a diverse group of phytophagous insects is associated with S. viarum, and some of them may have potential as biocontrol agents of S. viarum in Florida.

Wasmannia spp. (Hym., Formicidae) and insect damages to cocoa in Brazilian farms

Diagnostic insect damage to cocoa tree leaves and fruits were compared in situations with and without the presence of the little fire ants, Wasmannia auropunctata and the closely related and sympatric W. cf rochai. No significant differences in thrips, lepidopteran, or chrysomelid beetle damage to fruits, or to young and old leaves, were associated with these ants. However, significant increases of pseudococcids Planococcus citrii, associated with areas dominated by W. auropunctata, and to a lesser degree with W. cf rochai, were present. W. auropunctata has been reported to be a canopy mosaic dominant in cocoa farms, but the lack of reduced herbivore incidences and its lack of spatial permanence do not support favoring its populations for the management of phytophagous insect control.

First isolation of microorganisms from the gut diverticulum of Aedes aegypti (Diptera: Culicidae): New perspectives for an insect-bacteria association

We show for the first time that the ventral diverticulum of the mosquito gut (impermeable sugar storage organ) harbors microorganisms. The gut diverticulum from newly emerged and non-fed Aedes aegypti was dissected under aseptic conditions, homogenized and plated on BHI medium. Microbial isolates were identified by sequencing of 16S rDNA for bacteria and 28S rDNA for yeast. A direct DNA extraction from Ae. aegypti gut diverticulum was also performed. The bacterial isolates were: Bacillus sp., Bacillus subtilis and Serratia sp. The latter was the predominant bacteria found in our isolations. The yeast species identified was Pichia caribbica.

Impacts of enemy-mediated effects and the additivity of interactions in an insect trophic system

In this study, we used data from both experiments and mathematical simulations to analyze the consequences of the interacting effects of intraguild predation (IGP), cannibalism and parasitism occurring in isolation and simultaneously in trophic interactions involving two blowfly species under shared parasitism. We conducted experiments to determine the short-term response of two blowfly species to these interactions with respect to their persistence. A mathematical model was employed to extend the results obtained from these experiments to the long-term consequences of these interactions for the persistence of the blowfly species. Our experimental results revealed that IGP attenuated the strength of the effects of cannibalism and parasitism between blowfly host species, increasing the probability of persistence of both populations. The simulations obtained from the mathematical model indicated that IGP is a key interaction for the long-term dynamics of this system. The presence of different species interacting in a tri-trophic system relaxed the severity of the effects of a particular interaction between two species, changing species abundances and promoting persistence through time. This pattern was related to indirect interactions with a third species, the parasitoid species included in this study. © 2012 The Society of Population Ecology and Springer Japan.

Photodynamic and Antibiotic Therapy Impair the Pathogenesis of Enterococcus faecium in a Whole Animal Insect Model

Enterococcus faecium has emerged as one of the most important pathogens in healthcare-associated infections worldwide due to its intrinsic and acquired resistance to many antibiotics, including vancomycin. Antimicrobial photodynamic therapy (aPDT) is an alternative therapeutic platform that is currently under investigation for the control and treatment of infections. PDT is based on the use of photoactive dye molecules, widely known as photosensitizer (PS). PS, upon irradiation with visible light, produces reactive oxygen species that can destroy lipids and proteins causing cell death. We employed Galleria mellonella (the greater wax moth) caterpillar fatally infected with E. faecium to develop an invertebrate host model system that can be used to study the antimicrobial PDT (alone or combined with antibiotics). In the establishment of infection by E. faecium in G. mellonella, we found that the G. mellonella death rate was dependent on the number of bacterial cells injected into the insect hemocoel and all E. faecium strains tested were capable of infecting and killing G. mellonella. Antibiotic treatment with ampicillin, gentamicin or the combination of ampicillin and gentamicin prolonged caterpillar survival infected by E. faecium (P = 0.0003, P = 0.0001 and P = 0.0001, respectively). In the study of antimicrobial PDT, we verified that methylene blue (MB) injected into the insect followed by whole body illumination prolonged the caterpillar survival (P = 0.0192). Interestingly, combination therapy of larvae infected with vancomycin-resistant E. faecium, with antimicrobial PDT followed by vancomycin, significantly prolonged the survival of the caterpillars when compared to either antimicrobial PDT (P = 0.0095) or vancomycin treatment alone (P = 0.0025), suggesting that the aPDT made the vancomycin resistant E. faecium strain more susceptible to vancomycin action. In summary, G. mellonella provides an invertebrate model host to study the antimicrobial PDT and to explore combinatorial aPDT-based treatments.

Insect/Bt-cotton interactions: Are immunological variables and hemocyte ultrastructure in Podisus nigrispinus (Hemiptera: Pentatomidae) affected?

Recent studies have shown that ingestion by the army worm Spodoptera frugiperda of Cry1Ac toxin from Bt cotton promotes histochemical and ultrastructural changes in the digestive cells of the predatory pentatomid bug Podisus nigrispinus. Therefore, mindful of the changes in the midgut of the predator, which represents the first line of defence in this insect, our aim was to test the hypothesis that the consumption of Bt cotton-fed S. frugiperda by P. nigrispinus might lead to alterations in components of the immune system of P. nigrispinus. The Cry1Ac toxin level in the leaves of Bt cotton, nitric oxide, phenoloxidase activity, and total proteins were quantified by ELISA. Total and differential hemocyte counts were evaluated, and hemocyte ultrastructure analysis was undertaken. We found that ingestion of the prey fed daily with approximately 23 ± 0.70 ng g-1 Cry1Ac by wet weight of leaves, and expressed by the Bt cotton, induces small ultrastructural changes in the predator's granulocytes and plasmatocytes. However, these changes did not affect the total number and differential and humoral variables analyzed for the bug's hemocytes. © 2013 Copyright Taylor and Francis Group, LLC.

Responses of aquatic insect functional diversity to landscape changes in Atlantic forest

The Atlantic Forest domain, one of the 25 world's hotspots for biodiversity, has experienced dramatic changes in its landscape. While the loss of species diversity is well documented, functional diversity has not received the same amount of attention. In this study, we evaluated functional diversity of insects in streams utilizing three indices: functional diversity (FD), functional dispersion (FDis), and functional divergence (FDiv), seeking to understand the roles of three predictor sets in explaining functional patterns: (1) bioclimatic and landscape variables; (2) spatial variables; and (3) local environmental variables. We determined the amount of variation in different measures of functional diversity that was explained by each predictor set and their interplays using variation partitioning. Our study showed that variation in functional diversity is better explained by a set of variables linked to different scales dependent on spatial structures, indicating the importance of landscape and mainly environmental variables in the functional organization of aquatic insect communities, and that the relative importance of predictor sets depends on the indices considered. Variation in FD was better explained by the interplay among the three predictor sets and by local environmental variables, whereas variation in FDis was better explained by spatial variables and by the interplay between environmental and spatial variables. Variation in FDiv was not significantly explained by any predictors. Our study adds more evidence on the harmful effects caused by landscape changes on biodiversity in the Atlantic Forest, suggesting that these effects also influence the functional organization of stream insect communities. © 2013 The Author(s) Journal compilation © 2013 by The Association for Tropical Biology and Conservation.

A survey of DNA methylation across social insect species, life stages, and castes reveals abundant and caste-associated methylation in a primitively social wasp

DNA methylation plays an important role in the epigenetic control of developmental and behavioral plasticity, with connections to the generation of striking phenotypic differences between castes (larger, reproductive queens and smaller, non-reproductive workers) in honeybees and ants. Here, we provide the first comparative investigation of caste- and life stage-associated DNA methylation in several species of bees and vespid wasps displaying different levels of social organization. Our results reveal moderate levels of DNA methylation in most bees and wasps, with no clear relationship to the level of sociality. Strikingly, primitively social Polistes dominula paper wasps show unusually high overall DNA methylation and caste-related differences in site-specific methylation. These results suggest DNA methylation may play a role in the regulation of behavioral and physiological differences in primitively social species with more flexible caste differences. © 2013 Springer-Verlag Berlin Heidelberg.

Action of the insect growth regulator fluazuron, the active ingredient of the acaricide Acatak®, in Rhipicephalus sanguineus nymphs (Latreille, 1806) (Acari: Ixodidae)

The present study evaluated the efficacy of fluazuron (active ingredient of the acaricide Acatak®) and its effects on Rhipicephalus sanguineus nymphs fed on rabbits exposed to different doses of this insect growth regulator. Three different doses of fluazuron (20 mg/kg, 40 mg/kg, and 80 mg/kg) were applied on the back of hosts (via pour on), while distilled water was applied to the Control group. On the first day of treatment with fluazuron (24 h), hosts were artificially infested with R. sanguineus nymphs. Once fully engorged, nymphs were removed and placed in identified Petri dishes in Biochemical Oxygen Demand (BOD) incubator for 7 days. After this period, engorged nymphs were processed for ultramorphological analysis. The results revealed alterations in the ultramorphology of many chitinous structures (smaller hypostome and chelicerae, less sclerotized scutum, fewer sensilla, fewer pores, absence of grooves, marginal and cervical strips and festoons in the body, even the anal plaque was damaged) that play essential roles for the survivor of ticks and that can compromise the total or partial development of nymphs and emergence of adults after periodic molting. Our findings confirm the efficacy of fluazuron, a more specific and less aggressive chemical to the environment and human health, and that does not induce resistance, in nymphs of the tick R. sanguineus in artificially infested rabbits treated with this arthropod growth regulator (AGR), indicating that it could be used in the control of this stage of the biological cycle of the tick R. sanguineus. © 2013 Wiley Periodicals, Inc.

Análise dos processos de decomposição e sucessão ecológica em carcaças de suínos (Sus scrofa L.) mortos por disparo de arma de fogo e overdose de cocaína e protocolo de procedimento diante de corpo de delito

Pós-graduação em Biologia Geral e Aplicada - IBB