No abstract

Conhecida vulgarmente como lagarta-militar ou lagarta-do-cartucho, a Spodoptera frugiperda é uma das pragas agrícolas mais importantes do Brasil, devido seu hábito polífago e sua amplas distribuição geográfica. O uso de agentes entomopatogênicos vem contribuindo com o manejo desta praga, pois diminui os impactos causados pelos agroquímicos e proporciona uma agricultura sustentável. O objetivo deste trabalho foi avaliar a patogenicidade da bactéria entomopatogênica Bacillus thuringiensis e do vírus entomopatogênico Nucleopolyhedrovirus (HearNPV) quando aplicados diretamente sobre a lagarta S. frugiperda. O experimento foi feito com lagartas de 2o e 3o instares. Cada experimento foi composto por 5 tratamentos: T1: Testemunha (sem aplicação de entomopatógenos), T2: Agree®, T3: Xentari®, T4: Diplomata®; T5: Armigen® e 5 repetições por tratamento, cada repetição contendo 6 lagartas de 2o e 3o instares. Cada repetição foi constituída de uma placa de Petri (9 cm de diâmetro) com 1 inseto, totalizando 30 lagartas de cada instar por tratamento. A mortalidade foi avaliada diariamente até quinze dias após aplicação. Os dados da mortalidade acumulada foram submetidos à análise de variância (teste F), as médias serão comparadas pelo teste Scott-Knott a 5% de probabilidade e a eficiência dos bioinseticidas pela fórmula de Abbott. O bioinseticida Xentari® proporcionou maior média de mortalidade no 2o instar de S. frugiperda diferindo dos demais tratamentos, no 3o instar não houve diferença significativa entre os tratamentos.

The conversion of forests into open areas has large effects on the diversity and structure of native communities. The intensity of these effects may vary between regions, depending on the existence of native species adapted to open habitats in the regional pool or the time since habitat change. We assess the differences in species richness and functional diversity of dung beetle communities (Coleoptera: Scarabaeinae) between native forests and novel pasturelands of the Atlantic Forest and the Cerrado, two biomes with contrasting histories of human occupation in Brazil. We conducted standardized surveys in seven forest fragments and adjacent pastures in each region and measured 14 traits in individuals collected in each type of habitat at each particular site. We calculated functional richness, functional evenness, functional divergence, and community‐weighted mean of traits for each area, and analyzed individual variation through nested variance decomposition and Trait Statistics. Communities were richer and more numerous at the Cerrado. We did not find any consistent relationship between functional diversity and forest conversion beyond the changes in species diversity. Although landscape changes were more recent at the Cerrado, the colonization of the new habitat by native species already adapted to open habitats lessens the functional loss in this biome. This indicates that habitat change's effects on trait diversity depend on the regional species pool rather than on time since land conversion. Forest conversion effects were primarily due to internal filtering. The effects of external filtering only appear at the intraspecific variance level, with contrasting differences between the Cerrado, where traits related to relocation behavior and size are selected, and the Atlantic Forest, where selection operates for traits related to relocation behavior and flight. These results evidence the importance of considering individual variance to address the responses of dung beetle communities to forest conversion.

This research, under laboratory condition, evaluated the efficiency of different strains of entomopatogenic fungus Beauveria bassiana to control leaf-cutting ant Atta sexdens rubropilosa. Soldiers and workers were inoculated with suspensions containing 1.0x107, 1.0x108, 1.0x109 and 1.0x1010 con mL-1 and maintained in B.O.D, at 25±1°C, 70% RH and 12 hours of photophase, without food. The mortality was evaluated daily, with 15 days after inoculation. Experimental design was entirely random. The sporulation data were submitted to the analysis of variance and the LT50 values (in days) were obtained through the Probit analysis. All strains of B. bassiana were pathogenic, being workers more susceptible than soldiers. The strains IBCB 21 and IBCB 07 caused high percentages of confirmed mortality showing potential for use in the control of A. sexdens rubropilosa. Strain IBCB 21 was more virulent for workers, whereas isolated IBCB 07 was more virulent for soldiers. Both isolates presented no significant difference among tested concentrations.

Plants are one of the most vulnerable groups to fragmentation and habitat loss, that may affect community richness, abundance, functional traits, and genetic diversity. Here, we address the effects of landscape features on adaptive quantitative traits and evolutionary potential, and on neutral genetic diversity in populations of the Neotropical savanna tree Caryocar brasiliense. We sampled adults and juveniles in 10 savanna remnants within five landscapes. To obtain neutral genetic variation, we genotyped all individuals from each site using nine microsatellite loci. For adaptive traits we measured seed size and mass and grown seeds in nursery in completely randomized experimental design. We obtained mean, additive genetic variance (Va) and coefficient of variation (CVa%), which measures evolvability, for 17 traits in seedlings. We found that landscapes with higher compositional heterogeneity (SHDI) had lower evolutionary potential (CVa%) in leaf length (LL) and lower aboveground dry mass (ADM) genetic differentiation (QST). We also found that landscapes with higher SHDI had higher genetic diversity (He) and allelic richness (AR) in adults, and lower genetic differentiation (FST). In juveniles, SHDI was also positively related to AR. These results are most likely due to longer dispersal distance of pollen in landscapes with lower density of flowering individuals. Agricultural landscapes with low quality mosaic may be more stressful for plant species, due to the lower habitat cover (%), higher cover of monocropping (%) and other land covers, and edge effects. However, in landscapes with higher SHDI with high quality mosaic, forest nearby savanna habitat and the other environments may facilitate the movement or provide additional habitat and resources for seed disperses and pollinators, increasing gene flow and genetic diversity. Finally, despite the very recent agriculture expansion in Central Brazil, we found no time lag in response to habitat loss, because both adults and juveniles were affected by landscape changes.

Atualmente existem no mercado inúmeras substâncias químicas empregadas no controle de insetos-praga. Entre eles, os inseticidas são um grupo numeroso e destacado. Este trabalho teve como objetivo avaliar a compatibilidade “in vitro” entre os inseticidas Permetrina (Pounce®) e Acefato (Orthene®) e os isolados UFMS 06 e UFMS 07 do fungo Metarhizium rileyi. Para tanto, o crescimento micelial, produção e germinação dos esporos foram avaliados. Ao solidificar o meio de cultura contendo os inseticidas, foram inoculados o fungo M. rileyi e incubados por 7 dias, em câmara climatizada a 25±1 ºC, umidade relativa 70±10% e fotoperíodo de 12 horas. Para germinação dos esporos o período de incubação foi de 20 horas, nas mesmas condições citados anteriormente O índice biológico foi utilizada para o estabelecimento da classificação toxicológica dos inseticidas sobre o fungo. Os resultados mostraram que os produtos testados foram compatíveis com o fungo, podendo ser, portanto, utilizados no manejo integrado de pragas agrícolas por não afetarem o desenvolvimento do agente de controle biológico M. rileyi.

Esta proposta de atividade é voltada para alunos do ensino superior como material didático para o ensino de Genética da Conservação, mostrando como alguns princípios da genética de populações e quantitativa podem ser utilizados para compreender a resposta à seleção natural por meio de estudos da variação adaptativa das espécies. Os dados são hipotéticos e podem ser utilizados como simulação de aula prática, ou como uma atividade complementar à aula expositiva.

This study aimed to evaluate the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae on leaf-cutting ants Atta sexdens rubropilosa, under laboratory conditions. It was inoculated suspensions containing different concentrations of conidia on specimens of soldiers and workers, kept under controlled conditions. The mortality was verified daily until 15 days after inoculation. The experimental delineation was entirely random. Sporulation data were submitted to variance analysis and the average of the treatments were compared to each other by the Scott-Knott test. Probit analysis was performed to obtain the values of LT50 (in days). All isolates were pathogenic to A. sexdens rubropilosa, being more virulent for workers than for soldiers. Isolates IBCB 348, IBCB 410 and IBCB 425 were the most efficient in the mortality of the ants. Isolates IBCB 425 and UFGD 03 caused high percentages of confirmed mortality. The results showed that the tested isolates have the potential for using them as control agents of A. sexdens rubropilosa.