Interspecific insect relationships on Terminalia argentea (Myrtales: Combretaceae) trees in the Cerrado biome.

Terminalia argentea Mart. (Combretaceae), native to Brazil, is used in habitat restoration programs. Arthropods are bioindicators because their populations reflect changes in the environment. We evaluated the recovery of a degraded area by using ecological indices and analyzing arthropod interactions on T. argentea plants. The richness and diversity of sap-sucking Hemiptera and the abundance of tending ants and Sternorrhyncha predators increased with the number of T. argentea leaves. The correlation of the abundance of tending ants and Sternorrhyncha predators was positive with that of the sap-sucking Hemiptera, and the abundance of Sternorrhyncha predators was negative with that of tending ants and sap-sucking Hemiptera. The positive correlation between the abundance, richness, and diversity of insect groups and numbers of T. argentea leaves is an example of the bottom-up regulation mechanism, with the population dynamics of the lower trophic levels dictating those of higher trophic levels. The contribution of T. argentea, a host plant of many arthropods, to the recovery of ecological relationships between organisms in degraded ecosystems is important.

Diversity of entomopathogenic fungi from soils of eucalyptus and soybean crops and natural forest areas.

Soils present high fungal diversity, including entomopathogenic species. These fungi are used in pest control, providing easy production, multiplication, application, and dispersion in the field. The objective of the present study was to evaluate entomopathogenic fungal diversity in soils from eucalyptus and soybean crops and natural forest areas. These fungi were isolated using the "Bait Method" with Tenebrio molitor (Linnaeus, 1758) (Coleoptera: Tenebrionidae) larvae from 10 soil samples per area, collected at 10 cm deep in a zig-zag pattern. The isolated entomopathogenic fungi were cultivated in Petri dishes using PDA medium and their mycelia separated after seven days of incubation in a BOD-type chamber. Species of Aspergillus, Beauveria, Cordyceps, Fusarium, Metarhizium, Penicillium and Purpureocillium were identified. The "Bait Method" with T. molitor larvae is efficient to isolate entomopathogenic fungi with higher diversity from soils of the natural forest than the cultivated area.

Entomopathogenic Fungi, Isolated From Soils and Bemisia tabaci (Hemiptera: Aleyrodidae) Adults, to Manage the Eucalyptus Red Gum Lerp Psyllid Glycaspis brimblecombei (Hemiptera: Aphalaridae).

The parasitoid Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae), entomopathogenic fungi, and chemical insecticides are the main strategies to manage the eucalypts pest Glycaspis brimblecombei Moore. The objective of this study was to isolate and to identify entomopathogenic fungi, collected from Bemisia tabaci Gennadius adults in soybean and tomato crops, and from soil samples in eucalypts, soybean, and native forest areas to evaluate their potential to manage G. brimblecombei. Twelve Beauveria and Cordyceps isolates were selected and compared with the commercial products Boveril Beauveria bassiana Bals. (Hypocreales: Cordycipitaceae), Metarril Metarhizium anisopliae Metschn. (Hypocreales: Clavicipitaceae), and Octane Cordyceps fumosorosea Wize (Hypocreales: Cordycipitaceae) and their respective strains. The fungal isolates were diluted in 0.1% aqueous Tween 80 at a concentration of 1.0 × 108 conidia/ml and sprayed on the G. brimblecombei nymphs with or without lerps. Pest mortality was higher and the TL50 and TL90 lower with the isolates LCBPF 11 C. javanica Frieder. & Bally (Hypocreales: Cordycipitaceae), LCBPF 12 (C. fumosorosea), and LCBPF 67 (C. fumosorosea) from B. tabaci adults. Fungi of the genera Beauveria and Cordyceps developed and caused high mortality of G. brimblecombei nymphs with lerps. The B. bassiana, C. cateniannulata Liang (Hypocreales: Cordycipitaceae), C. fumosorosea, C. javanica, and M. anisopliae isolates showed potential to manage G. brimblecombei. The lerp of this insect enhances entomopathogenic fungus development as a source of inoculum accelerating G. brimblecombei nymph mortality. Entomopathogenic fungi isolated from insects and soils are effective against G. brimblecombei and the presence of the lerp of this insect increases the effectiveness of its control.

The survival, development, and reproduction of Gonipterus platensis (Coleoptera: Curculionidae) on the main Eucalyptus (Myrtaceae) genotypes planted in Brazil.

Background: Gonipterus platensis Marelli (Coleoptera: Curculionidae) is the main defoliating beetle of Eucalyptus L'Hér. (Myrtaceae) plants worldwide. The suitability of Eucalyptus to this pest varies among host plant genotypes. The objective of this study was to evaluate the development, reproduction, and survival of G. platensis on Eucalyptus species and hybrids to assess their suitability to this insect pest in Brazil. Methods: The survival, development, and reproduction parameters were evaluated with G. platensis feeding leaves of Eucalyptus camaldulensis Dehnh., Eucalyptus grandis W. Hill., Eucalyptus urophylla S.T. Blake and on the hybrids of E. grandis ×E. urophylla 'H13' and 'VR3748' in the laboratory. Results: The duration of the larval stage of G. platensis was shorter on E. urophylla. The pupal stage and the period from larva to adult were equally shorter on E. urophylla and E. camaldulensis. The viability of instars of this insect was low on both E. grandis and E. camaldulensis. The complete lifespan, oviposition period and reproduction parameters of G. platensis were greater on E. urophylla, lower on E. camaldulensis and E. grandis, and intermediate on both hybrids tested. Synthesis: Eucalyptus urophylla is the most suitable host for G. platensis survival, development, and reproduction, while E. grandis and E. camaldulensis are the least suitable.

Linking land-use and land-cover transitions to their ecological impact in the Amazon.

Human activities pose a major threat to tropical forest biodiversity and ecosystem services. Although the impacts of deforestation are well studied, multiple land-use and land-cover transitions (LULCTs) occur in tropical landscapes, and we do not know how LULCTs differ in their rates or impacts on key ecosystem components. Here, we quantified the impacts of 18 LULCTs on three ecosystem components (biodiversity, carbon, and soil), based on 18 variables collected from 310 sites in the Brazilian Amazon. Across all LULCTs, biodiversity was the most affected ecosystem component, followed by carbon stocks, but the magnitude of change differed widely among LULCTs and individual variables. Forest clearance for pasture was the most prevalent and high-impact transition, but we also identified other LULCTs with high impact but lower prevalence (e.g., forest to agriculture). Our study demonstrates the importance of considering multiple ecosystem components and LULCTs to understand the consequences of human activities in tropical landscapes.

Gene Expression Profile Analysis is Directly Affected by the Selected Reference Gene: The Case of Leaf-Cutting Atta Sexdens.

Although several ant species are important targets for the development of molecular control strategies, only a few studies focus on identifying and validating reference genes for quantitative reverse transcription polymerase chain reaction (RT-qPCR) data normalization. We provide here an extensive study to identify and validate suitable reference genes for gene expression analysis in the ant Atta sexdens, a threatening agricultural pest in South America. The optimal number of reference genes varies according to each sample and the result generated by RefFinder differed about which is the most suitable reference gene. Results suggest that the RPS16, NADH and SDHB genes were the best reference genes in the sample pool according to stability values. The SNF7 gene expression pattern was stable in all evaluated sample set. In contrast, when using less stable reference genes for normalization a large variability in SNF7 gene expression was recorded. There is no universal reference gene suitable for all conditions under analysis, since these genes can also participate in different cellular functions, thus requiring a systematic validation of possible reference genes for each specific condition. The choice of reference genes on SNF7 gene normalization confirmed that unstable reference genes might drastically change the expression profile analysis of target candidate genes.

Persistence of fipronil residues in Eucalyptus seedlings and its concentration in the insecticide solution after treatment in the nursery.

Eucalyptus seedlings are normally protected from underground termites (Isoptera: Termitidae) by immersing them in insecticide solutions. Fipronil (phenylpyrazole) is the most frequently used product to protect seedlings in the field for up to 6 months after application. This is performed just prior to planting. However, the persistence of this product in seedlings that are treated and subjected to irrigation several days prior to planting has not yet been evaluated. This study aims to quantify the fipronil concentration in the substratum and roots of the seedlings treated and subjected to irrigation for up to 56 days prior to planting and to quantify this insecticide concentration in the solutions, without continuous stirring, for 120 min. The quantitative determination of fipronil in the seedlings and in the insecticide solution was done by high-performance liquid chromatography (HPLC) with an ultraviolet (UV) detector. It was found that irrigation up to 56 days, performed in the nurseries, did not decrease the fipronil concentration in the seedlings. The absence of stirring reduced the fipronil concentration in the insecticide solution, necessitating a homogenization system to maintain the recommended concentration of this product, to effectively treat the eucalyptus seedlings. The seedling treatment with fipronil can be conducted strictly in the nursery, reducing cost and environmental risks.

The impact of coffee and pasture agriculture on predatory and omnivorous leaf-litter ants.

Ants are known to function as reliable biological indicators for habitat impact assessment. They play a wide range of ecological roles depending on their feeding and nesting habits. By clustering ants in guilds, it is possible both to assess how agriculture and forest fragmentation can disturb ant communities and to predict the ecological impacts due to losses of a specific guild. This study aimed at determining the impact of non-shaded coffee and pasture agriculture on predatory and omnivorous guilds of leaf-litter ants of Atlantic Forest fragments in Minas Gerais, Brazil. Both coffee and pasture agriculture influenced leaf-litter ant community, although coffee was more disruptive than pasture. Coffee agriculture not only disturbed the diversity of predatory ants, but also negatively affected the number of predatory and omnivorous ants when compared to forest fragments. In contrast, pasture agriculture only disrupted the abundance of predatory ants. Fragment edges skirting crops were negatively affected in terms of leaf-litter ant abundance, but not diversity. Cluster analysis showed that forest fragments were similar irrespective of the cultivation, but the borders were similar to the crop. The study assessed agriculture impact by surveying ant guilds, and revealed that the predatory guild is more susceptible than omnivorous ants.

[Rapid evaluation of ant diversity in land use systems in southern Bahia, Brazil]. / Avaliação rápida da diversidade de formigas em sistemas de uso do solo no sul da Bahia.

We aimed to compare the soil ant diversity in different land use systems from Atlantic Forest area, in Southern Bahia state, Brazil. The ants were sampled in 16 sites: two primary forest sites (un-logged forest); three young secondary forests (<8 years old); three intermediate secondary forests (8-20 years old); three old secondary forests (>20 years old); three Eucalyptus grandis plantations (3-7 years old), and two introduced pastures. Each site was sampled in three sampling points 15 m apart, and distant over 50 m from the site edge. In each sampling point we gathered the litter from a 1 m² and extracted the ants with Winkler extractors during 48h. We found 103 ant species from 29 genera and eight subfamilies. The five richest genera were Pheidole (19 species), Solenopsis (8), Apterostigma (10), Hypoponera (7) e Paratrechina (5). The highest ant richness density was found in the primary forest (7.4 species/sample; S = 37; n = 5); followed by the old secondary forest (5.33 species/sample; S = 48; n = 9); young secondary forest (5.25 species/sample; S = 42, n = 8); eucalyptus plantation (4.22 species/sample; S = 38, n = 9), intermediate secondary forest (3.5 species/sample; S = 35, n = 10, and introduced pasture (2.67 species/sample; S = 16, n = 6). The ecosystems with higher structural complexity showed the highest ant richness density by sample. Therefore, in the Atlantic Forest region, the eucalyptus plantation is a better alternative of land use to conserve the ant biodiversity than pastures, and quite similar to native secondary forests in ant community characteristics.

Avaliação rápida da diversidade de formigas em sistemas de uso do solo no sul da Bahia / Rapid evaluation of ant diversity in land use systems in southern Bahia, Brazil

We aimed to compare the soil ant diversity in different land use systems from Atlantic Forest area, in Southern Bahia state, Brazil. The ants were sampled in 16 sites: two primary forest sites (un-logged forest); three young secondary forests (<8 years old); three intermediate secondary forests (8-20 years old); three old secondary forests (>20 years old); three Eucalyptus grandis plantations (3-7 years old), and two introduced pastures. Each site was sampled in three sampling points 15 m apart, and distant over 50 m from the site edge. In each sampling point we gathered the litter from a 1 m² and extracted the ants with Winkler extractors during 48h. We found 103 ant species from 29 genera and eight subfamilies. The five richest genera were Pheidole (19 species), Solenopsis (8), Apterostigma (10), Hypoponera (7) e Paratrechina (5). The highest ant richness density was found in the primary forest (7.4 species/sample; S = 37; n = 5); followed by the old secondary forest (5.33 species/sample; S = 48; n = 9); young secondary forest (5.25 species/sample; S = 42, n = 8); eucalyptus plantation (4.22 species/sample; S = 38, n = 9), intermediate secondary forest (3.5 species/sample; S = 35, n = 10, and introduced pasture (2.67 species/sample; S = 16, n = 6). The ecosystems with higher structural complexity showed the highest ant richness density by sample. Therefore, in the Atlantic Forest region, the eucalyptus plantation is a better alternative of land use to conserve the ant biodiversity than pastures, and quite similar to native secondary forests in ant community characteristics.

Eficiência de produtos termonebulígenos no controle de Atta laevigata (Hymenoptera: Formicidae) em plantio de eucalipto / Efficiency of products for thermonebulization on the control of Atta laevigata (Hymenoptera: Formicidae) in eucalypus plantations

Avaliou-se a eficiência de produtos termonebulígenos, a base de clorpirifós ou de extratos vegetais, comparativamente ao uso de isca formicida, a base de sulfluramida, no controle de Atta laevigata (F. Smith, 1858) (Hymenoptera: Formicidae). Foi avaliada a percentagem de paralisação das atividades de corte de folhas e de movimentação de formigas de A. laevigata aos três, 12, 36, 63 e 86 dias após a aplicação dos tratamentos. Na última avaliação, os formigueiros foram abertos para a verificação da eficiência de controle. Todos os produtos testados apresentaram alta percentagem de paralisação das atividades de corte e de movimentação das formigas aos três e 12 dias após a aplicação, respectivamente. Os produtos a base de clorpirifós e um a base de extratos vegetais apresentaram alta eficiência no controle de A. laevigata, sendo mais efetivos que a isca formicida testada.

The efficiency of products formulated with chlorpyrifos or plants extracts in thermonebuzation was evaluated and compared to the use of the granulated bait formulated with sulfluramid in the control of Atta laevigata (F. Smith, 1858) (Hymenoptera: Formicidae). The cutting activity and the movement of ants on the colonies were evaluated at three, 12, 36, 63 and 86 days after the application of the treatments. The colonies of these ants were excavated in the last evaluation to obtain the efficiency of each product. All products stopped the cutting activity and movements of the individuals of A. laevigata three and 12 days after their application, respectively. Products formulated with chlorpyrifos and one with plant extracts were more efficient than granulated bait.

Ocorrência e recomendações para o manejo de Sirex noctilio Fabricius (Hymenoptera, Siricidae) em plantios de Pinus patula (Pinaceae) em Minas Gerais, Brasil / Occurrence and management recommendations of Sirex noctilio Fabricius (Hymenoptera, Siricidae) on Pinus patula (Pinaceae) plantations in the state of Minas Gerais, Brazil

A vespa-da-madeira Sirex noctilio Fabricius, 1793 (Hymenoptera, Siricidae) é a praga mais importante das florestas cultivadas com Pinus spp. no Brasil. Foi introduzida no Rio Grande do Sul em 1988 e sua dispersão ficou restrita aos estados do sul do país até 2004, quando foi detectada em São Paulo. Neste trabalho é relatada a ocorrência de S. noctilio em plantios de Pinus patula em Minas Gerais, em janeiro de 2005. São discutidas algumas medidas que podem ser adotadas para restringir a dispersão de S. noctilio na região Sudeste.

The woodwasp Sirex noctilio Fabricius, 1793 (Hymenoptera, Siricidae) is the most important pest on Pinus spp. in Brazil. It was introduced in the state of Rio Grande do Sul in 1988 and dispersed through the southern states. In 2004 it was detected in São Paulo state. In this work, it is reported the occurrence of S. noctilio in the state of Minas Gerais, in January 2005, on commercial areas of Pinus patula. It is discussed some measures that can be adopted to restrict its spread in the southeastern region.

Plano de amostragem de Acromyrmex spp. (Hymenoptera: Formicidae) em áreas de pré-plantio de Pinus spp / Acromyrmex spp. (Hymenoptera: Formicidae) sampling plan in Pinus spp. pre-planting areas

Realizou-se um estudo para elaborar um plano de amostragem de formigas cortadeiras em área de pré-plantio florestal, na empresa Bosques del Plata situada no Departamento de Santo Tomé, província de Corrientes, Argentina. O trabalho teve como objetivo estudar a distribuição espacial de formigueiros do gênero Acromyrmex em área de pré-plantio de Pinus spp., determinar o tamanho ótimo de parcelas e estimar a intensidade amostral desse gênero de formigas. Concluiu-se que a distribuição espacial dos ninhos de Acromyrmex spp. em Corrientes-Argentina, se ajusta ao modelo casual, com o tamanho ótimo de parcela para amostrar a densidade de formigueiros (ninhos.ha-1) de 700m² (10x70m) e a intensidade amostral ótima de 10,5 por cento da área total para um erro esperado de 24 por cento.

Impacto de iscas formicidas granuladas sobre a mirmecofauna não-alvo em eucaliptais segundo duas formas de aplicacação / Impact of formicid granulated baits on non-target ants in eucalyptus plantations according to two forms of application

Avaliou-se o efeito do uso localizado e do uso sistemático de iscas granuladas destinadas ao controle de formigas cortadeiras sobre a comunidade de formigas não-alvo da serapilheira em eucaliptais do município de Bom Despacho, Minas Gerais. As formigas foram coletadas utilizando-se armadilhas de Winkler, em três ocasiões: oito dias antes da distribuição das iscas, e oito e sessenta dias após, extraindo-se a mirmecofauna de 50 amostras de 1 m² de serapilheira. Coletou-se o total de 102 espécies, pertencentes a seis subfamílias. O caso particular de sete espécies de formigas mais freqüentes foi analisado com mais detalhes no intuito de avaliar mais precisamente as conseqüências dos tratamentos inseticidas. O estudo mostrou que o controle sistemático causou impacto negativo maior e mais prolongado na comunidade de formigas do que o controle localizado.

The effect of localized and systematic use of granulated bait for cutting ant control was assessed on a community of non-target ants in eucalyptus in the municipality of Bom Despacho, Minas Gerais State, Brazil. The ants were collected in Winkler traps on three occasions: eight days before bait distribution, eight and sixty days after distribution by removing the mirmecofauna from 50 1-m² samples of litter. A total of 102 species was collected belonging to six sub-families. The seven most frequent ant species were analyzed in more detail to assess more precisely the consequences of insecticide treatments. The study showed that systematic control caused negative and more prolonged impact on the ant community than localized control.

Diversidade de formigas (Hymenoptera: Formicidae) da serapilheira em eucaliptais (Myrtaceae) e área de cerrado de Minas Gerais / Ant (Hymenoptera: Formicidae) diversity in Eucalyptus (Myrtaceae) plantations and cerrado litter in Minas Gerais, Brazil

The inventory of the ant fauna in a cerrado area and in eucalypt plantations with five classes of understory ages, has been carried out in Bom Despacho (MG), in the aim to evaluate the effect of plantation age on the diversity of native cerrado ants. Fifteen areas of eucalypt have been sampled, being three per age class, as follows: areas with understory of 0 to 2, 2 to 4, 4 to 6, 6 to 8 and 8 to 10 years old, respectively). The same has been made in a native vegetation area used as control . The ants from the litter have been extracted using Winkler sacks. One hundred and forty three ant species have been collected, belonging to six subfamilies, being 67 in the native area (50 samples) and 133 in the eucalypt plantations (750 samples, corresponding to an average of 52 species per group of 50 samples, or sampled area). With the Chao 2 diversity estimator index, there is no significant differences between areas (Kruskal-Wallis, P>0.05). It has been demonstrated that most of the species found in native vegetation occur also in the eucalypt plantations, although these ones present a drastic diminution of the species density, suggesting that the ant regional richness do not depend on the complexity of the habitat, because the cerrado ant fauna is well conserved in the eucalypt plantations, contradicting most of the literature on this subject.

O levantamento da fauna de formigas foi realizado em uma área de vegetação nativa de cerrado e em eucaliptais com sub-bosque de cinco classes de idade, em Bom Despacho (MG), com o objetivo de avaliar o efeito da idade de eucaliptais sobre a diversidade de formigas nativas do cerrado. Foi utilizado um total de 15 talhões de eucalipto sendo três para cada classe de idade: talhões com sub-bosque de 0-2, 2-4, 4-6, 6-8 e 8-10 anos de idade, respectivamente, e ainda uma reserva nativa que serviu para comparações com os talhões. Para a coleta das formigas da serapilheira foi utilizado o método do extrator de Winkler. Foram coletadas 143 espécies de formigas, pertencentes a seis subfamílias, sendo 67 espécies na área de vegetação nativa (50 amostras) e 133 espécies nos eucaliptais (totalizando 750 amostras, o que corresponde à média de 52 espécies por grupo de 50 amostras, ou seja, por área amostrada). De acordo com o estimador de riqueza de Chao 2, não houve diferença significativa entre as áreas (Kruskal-Wallis, P>0,05). No entanto, a maioria das espécies encontradas no cerrado foi também encontrada nos eucaliptais, apesar de estes apresentarem uma drástica diminuição na densidade de espécies. Isso sugere que a riqueza em espécies de formigas na região estudada não depende somente da complexidade dos ambientes estudados, pois a fauna de formigas da vegetação nativa fica conservada nos eucaliptais, contradizendo a maioria dos trabalhos que tratam do assunto.

EFICIÊNCIA DE ISCAS GRANULADAS À BASE DE SULFLURAMIDA E DE CLORPIRIFÓS NO CONTROLE DE Atta sexdens sexdens(HYMENOPTERA: FORMICIDAE), NO TRÓPICO ÚMIDO

This research was developed in hibrid urograndis (Eucalyptus urophylla Eucalyptus grandis)plantation belonging to Jari Celulose S.A., in Pará State, Brazil, from August 1994 to January 1995. The objective was to test one granulated bait with sulfluramid and three others with chlorpirifos in three dosages compared to 10 grams of dodecachlor (0.45%) bait per square meter of ant nest against Atta sexdens sexdens(Hymenoptera: Formicidae). The bait with sulfluramid showed 77.78%; 100.00%; and 88.90% efficiency against A. sexdens sexdensat 6, 8, and 10 grams while the dodecachlor bait showed 100.00% control. The other baits and dosages showed efficiency below 45.00%.

Este trabalho foi realizado em plantios de eucalipto urograndis (Eucalyptus urophylla Eucalyptus grandis)da Jari Celulose S.A., no município de Almeirim, Pará, no período de agosto/94 a janeiro/95. Foi testada a eficiência de uma isca granulada com sulfluramida e de três outras com clorpirifós, em três dosagens cada por metro quadrado de formigueiro, no controle de Atta sexdens sexdens(Hymenoptera: Formicidae). Os resultados foram comparados com os de uma isca à base de dodecacloro (0,45%) a 10 gramas por metro quadrado de formigueiro. A isca granulada com sulfluramida a 6, 8 e 10 gramas por metro quadrado de formigueiro apresentou 77,78%, 100,00% e 88,90% de controle, respectivamente, assemelhando-se à isca a base de dodecacloro que apresentou 100,00% de formigueiros mortos. As outras iscas, em qualquer dosagem, apresentaram eficiência abaixo de 45,00%.