ResumoA falta ou excesso de água no solo são prejudiciais ao desenvolvimento das plantas. Assim, o objetivo deste trabalho foi avaliar o crescimento de plantas de girassol em diferentes capacidades de retenção de água (CRA). O experimento foi realizado em casa de vegetação, com a variedade de girassol Embrapa 122/V-2000, sob o delineamento experimental em blocos casualizados com quatro tratamentos (60% CRA, 80% CRA, 100% CRA e condição de alagamento) e quatro repetições. As plantas foram avaliadas semanalmente entre os estádios V6 (caracterizado pela presença de seis folhas com no mínimo 4,0 cm) ao R4 (inicio da florescência). Avaliou-se a altura das plantas, diâmetro de caule, teor de clorofila, matéria seca das folhas, do caule, da parte aérea e das raízes, número de folhas, área foliar, e a relação entre a matéria seca da raiz e da parte aérea. Os resultados mostraram que as plantas de girassol apresentaram maior altura e diâmetro de colmo quando submetidas à maior disponibilidade de água. Nos tratamentos com estresse hídrico o aumento do teor de clorofila foi limitado, e nos tratamentos com maior disponibilidade hídrica o teor inicialmente aumentou, mas, nas últimas avaliações decresceu. Apesar da relação raiz/parte aérea ter apresentado maiores valores para o tratamento 60% da CRA, a área foliar, número de folhas, matéria seca do caule, da raiz, e da folha apresentou menores valores a 60% da CRA. Portanto, o melhor desenvolvimento dessas plantas foi observado quando submetidas a 80 e 100% da CRA. Palavras-chave: Ácido abscísico, estresse hídrico, etileno, Helianthus annuus, hipoxia AbstractUsually the lack or excess of water in the soil is harmful to plant development. Therefore, our objective was to evaluate the growth of sunflower plants under different water holding capacities (WHC). Trials were conducted in a greenhouse with plants of the sunflower cultivar Embrapa 122/V-2000. The experimental design was a randomized complete block with four treatments: 60%, 80% and 100% of WHC and a flooding level with four replications. Plants were evaluated weekly between stages V6 (with six leaves and 4.0 cm tall) to R4 (flowering). We evaluated the plant height, stem diameter, leaf chlorophyll content, leaves, stems, shoot and root dry matter, number of leaves, leaf area, and the relationship between root and shoot dry matter. The results showed that the sunflower plants had greater

A recent shift in managing insect resistance to genetically engineered (GE) maize consists of mixing non-GE seed with GE seed known as “refuge in a bag”, which increases the likelihood of predators encountering both prey fed Bt and prey fed non-Bt maize. We therefore conducted laboratory choice-test feeding studies to determine if a predator, Harmonia axyridis, shows any preference between prey fed Bt and non-Bt maize leaves. The prey species was Spodoptera frugiperda, which were fed Bt maize (MON-810), expressing the single Cry1Ab protein, or non-Bt maize. The predators were third instar larvae and female adults of H. axyridis. Individual predators were offered Bt and non-Bt fed prey larvae that had fed for 24, 48 or 72 h. Ten and 15 larvae of each prey type were offered to third instar and adult predators, respectively. Observations of arenas were conducted at 1, 2, 3, 6, 15 and 24 h after the start of the experiment to determine the number and type of prey eaten by each individual predator. Prey larvae that fed on non-Bt leaves were significantly larger than larvae fed Bt leaves. Both predator stages had eaten nearly all the prey by the end of the experiment. However, in all combinations of predator stage and prey age, the number of each prey type consumed did not differ significantly. ELISA measurements confirmed the presence of Cry1Ab in leaf tissue (23–33 µg/g dry weight) and S. frugiperda (2.1–2.2 µg/g), while mean concentrations in H. axyridis were very low (0.01–0.2 µg/g). These results confirm the predatory status of H. axyridis on S. frugiperda and that both H. axyridis adults and larvae show no preference between prey types. The lack of preference between Bt-fed and non-Bt-fed prey should act in favor of insect resistance management strategies using mixtures of GE and non-GE maize seed.

Harmonia axyridis is a predator of aphids and other soft-bodied insects. This coccinellid, native to Asia, has invaded North America, Europe, South America and Africa. We report the first detection of H. axyridis in the Brazilian state of Mato Grosso do Sul, and review its current known geographic distribution in Brazil. Based on experiences from other parts of the world already invaded by H. axyridis, recommendations are provided to maximize the potential benefits offered by this species, while minimizing the potential adverse impacts that it can cause.

O objetivo deste trabalho foi verificar o tipo de interação entre formigas e os cupins os quais habitam o mesmo ninho. Os experimentos foram de duas maneiras: A- para testar a relação de predação, os tratamentos usados foram: três formigas e um cupim, três formigas e três cupins, e três formigas e doze cupins; B- para testar a relação de proteção os tratamentos foram: três formigas e três cupins de um mesmo ninho e três formigas de um ninho diferente. Para verificar predação foram testadas diferentes origens de formigas e cupins. Os testes foram em arenas e placas de Petri. Os comportamentos observados foram: não responde; contato e abandono; agarra o cupim e luta. As espécies estudadas foram Camponotus sp. e Cornitermes silvestrii Emerson. No experimento A, nas arenas foi observado o comportamento de contato e abandono das formigas sobre um cupim significativamente diferente para formigas que não co-habitava com o cupim, já para um grupo de cupins o comportamento foi não responde. Na placa de Petri as formigas responderam ao contato com os cupins com comportamento de contato e abandono, morder e luta com o cupim, mas não houve diferença estatística entre os comportamentos. No experimento B observou-se luta entre as formigas de ninhos diferentes. Os experimentos mostraram que as formigas que co-habitam cupinzeiros não tiveram nenhuma resposta agressiva ou de predação com relação aos cupins dos quais co-habitam, mas também não tiveram comportamento de proteção com os mesmos, sugerindo que esta interação entre formigas e cupins é de inquilinismo. Behavior of Ants (Hymenoptera: Formicidae) Co-inhabit of Termites (Isoptera: Termitidae) in grassland. Abstract. The aim of this study was to verify the kind of interactions between ants and termites that habit the same nest. Two kinds of experiments were done: A- to test the relation of predation, we used three ants and one termite, three ants and three termites and three ants and twelve termites; B- to test the relation of protection, we used three ants and three termites of the same nest and three ants of another nest. To verify predation, tests from distinct origins of ants and termites were done. The tests were composed by a hunting arena and glass Petri dishes. The observed behaviors were: no response; avoidance; ant grab the termite; and fight. The species studied were ants Camponotus sp. with termites Cornitermes silvestrii Emerson. In test A, the avoidance and abandoning behavior of the ants in the hunting arena regarding termite was significantly different for ants of different termite nests, and in another group of termites there was no response observed. In the glass Petri dish the ants responded at the contact with the termites: avoidance, to bite the termite and fight, but it wasn’t statistically different. And test B were observed fight between ants from different nests. The experiments showed that ants co-inhabit with termite didn’t have any aggressive response or predation regarding termites that they co-inhabit, but also didn’t have behavior protection to them, suggesting that interaction between ants and termites is inquilinism.

Insect-resistant genetically modified (GM) plants have been cultivated in several countries on a large scale. These plants express the Cry toxins from the bacterium Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) (Bt), which confers target-pest resistance to plants. Studies on the effects of GM plants on nontarget organisms are important to assess the technology’s impact on biodiversity. The objective of this study was to determine whether there are differences in the species richness and composition of ants and ground beetles in Bt maize (four different toxins: Cry1Ab, Cry1F, and Cry1A.105/Cry2Ab2) and conventional isoline (non-Bt) fields, in the first (summer) and second (winter) cropping seasons in 13 localities of Mato Grosso do Sul State, Brazil, over a 2-yr period (2009–2011). The assessment of Coleoptera and Formicidae species was performed using pitfall traps placed in fields throughout the period of vegetative growth and maturation of plants. Data were analyzed using faunistic indices of species richness, ordination by nonmetric multidimensional scaling, and multivariate analysis of variance. No statistically significant difference was found in the species richness of ant and ground beetle communities when comparing sites of Bt with those of non-Bt maize. Overall, Bt technology did not affect the composition of ant and ground beetles; however, municipality and cropping season exerted influence on the beetle composition. Some species were only observed in the first crop, whereas others were only observed in the second crop. This research suggests that Bt maize does not affect ant and ground beetle populations differently from its isoline.