Does organic management of agroecosystems contribute to the maintenance of the richness of ants? This study assessed the richness of ant species in organically farmed crop agroecosystems of different ages located in the southern state of Paraná, Brazil. During the sampling, the pitfalls that were active during May/August 2009 and from October 2009 to February 2010 were used. A total of 11,874 ants belonging to five subfamilies was sampled, comprising 18 genera and 48 species. The subfamily Myrmicinae (S = 27) had the highest richness, followed by the genera Pheidole (S = 10), Solenopsis (S = 7), Formicinae (S = 3), Camponotus (S = 5), and Brachymyrmex (S = 5). The average difference between the observed richness (Sobs) and the estimated richness (Chao2) was 10.9%. Ant assemblages belonging to agroecosystems under organic management for long times presented the greatest richness, indicating that this system contributes to the maintenance of ant diversity. Key words: Atlantic forest. Biodiversity. Conservation. Pheidole. Richness. ResumoO sistema de manejo orgânico de agroecossistemas contribui para a manutenção da diversidade de formigas? Este trabalho avaliou a riqueza de formigas presentes em lavouras inseridas em agroecossistemas de manejo orgânico, com tempos de integralização diferentes, localizados no sul do Estado do Paraná, Brasil. Na amostragem, foram utilizadas pitfalls que permaneceram ativas nos períodos de maio a agosto de 2009 e outubro de 2009 a fevereiro de 2010. Foram amostradas 11.874 formigas pertencentes a cinco subfamílias, 18 gêneros e 48 espécies. Destacou-se em riqueza a subfamília Myrmicinae (S = 27) e os gêneros Pheidole (S = 10) e Solenopsis (S = 7). Também Formicinae (S = 3) e os gêneros Camponotus (S = 5) e Brachymyrmex (S = 5). A diferença média entre a riqueza observada (Sobs) e a estimada (Chao 2) foi de 10,9%. Assembleias pertencentes aos agroecossistemas com maior tempo de manejo orgânico foram as mais ricas, indicando que este sistema contribui para a manutenção da diversidade de formigas. Palavras-chave: Mata Atlântica. Biodiversidade. Conservação. Pheidole. Riqueza.
Recent papers about invasive plants in Brazil have highlighted the scarcity of criteria for determining invasiveness status. Here, we reviewed papers published in academic journals before March 2012, together with undergraduate monographs, theses and dissertations and abstracts from meetings in ecology, botany and related fields, in order to list plants reported as invasive and verify the criteria used. A total of 124 works were listed, of which 45.9% reported quantitative samples and 35% dealt with Atlantic Forest, 18.5% with Cerrado and 17.8% with Caatinga, the most affected vegetation domains. Invasive behavior was supported by field data for only 54 alien species. Actual figures could be larger; however, the need for further research cannot be used as a justification for inaction in terms of public policy, and the precautionary principle should be employed in implementing temporary solutions in order to avoid irreversible damage.
A polinização é um serviço ecossistêmico de extrema importância no ambiente natural, garantindo muitos benefícios à biodiversidade e à manutenção dos ecossistemas. O presente trabalho teve como objetivo investigar a diversidade da apifauna e delinear as redes de interações entre espécies de plantas e abelhas em áreas de várzea, na Floresta Nacional de Três Barras (SC, Brasil). Foram selecionadas três áreas de várzeas para a amostragem de abelhas nas flores, cada uma com seis parcelas de 1 ha. As coletas ocorreram durante a primavera e o verão de 2016 e 2017. Coletaram-se 1.656 abelhas, distribuídas em 99 espécies. Apidae foi a família mais abundante e Halictidae a família mais rica em espécies. As espécies mais abundantes foram Apis mellifera scutellata, Melipona (Eomelipona) marginata, Plebeia emerina, Trigona spinipes, Rhophitulus flavitarsis, Tetraglossula sp., Scaptotrigona bipunctata, Bombus (Thoracobombus) pauloensis. As interações entre as espécies de abelhas e plantas apresentaram um padrão generalista; a rede mostrou-se significativamente aninhada e modular. A comunidade de abelhas nos campos de várzea evidenciou alta riqueza de espécies em comparação a outros levantamentos na Região Sul do Brasil, especialmente se considerarmos que a área de estudo é um ambiente mais restrito. As espécies mais abundantes foram as eussociais, as quais são diversificadas nas florestas neotropicais, com destaque para Apis mellifera scutellata, uma espécie exótica, bastante populosa e generalista.
Corn weevil (Sitophilus zeamais) may cause great losses in the crop and in stored corn grains. This insect is controlled with the use of chemical insecticides, which may cause serious damage to human health. One alternative of control is the use of inert dusts. The objective of this study was to evaluate the efficiency of inert dusts in the control of S. zeamais under laboratory conditions. The experiment was conducted in 2014, in a completely randomized design, and the treatments consisted of basalt dust with three different granulometries (A, B and C) and diatomaceous earth, each of which at the doses of 2 and 4 kg t-1 and a control (no application). Each treatment had four replicates, and the sample unit consisted of 20 g of corn grains infected with 10 adults of S. zeamais kept in temperature-controlled chamber at 25 °C, 70% RH and photophase of 12 h. The dust efficiency was calculated using the equation of Abbott. The mortality rate was higher with the use of diatomaceous earth, reaching 100% after 5 days of exposure and the percentage of control for basalt dusts, 29 days after treatment, was above 80%.
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