Predation risk effects on larval development and adult life of Aedes aegypti mosquito.

Biological control is one of the methods available for control of Aedes aegypti populations. We used experimental microcosms to evaluate the effects of actual predation and predation risk by dragonfly larvae (Odonata) on larval development, adult longevity, and adult size of Ae. aegypti. We used six treatments: control, removal, variable density cues (Cues VD), fixed density cues (Cues FD), variable density predator (Predator VD), and fixed density predator (Predator FD) (n = 5 each). Predator treatments received one dragonfly larva. Cue treatments were composed of crushed Ae. aegypti larvae released into the microcosm. For the FD treatments, we maintained a larval density of 200 individuals. The average mortality of Ae. aegypti larvae in the Predator VD treatment was used as the standard mortality for the other treatments. Mosquitoes from the Predator VD and Cues VD treatments developed faster, and adults were larger and had greater longevity compared to all other treatments, likely due to the higher food availability from larval density reduction. High larval density negatively affected larval developmental time, adult size, and longevity. Males were less sensitive to density-dependent effects. Results from this study suggest that the presence of predators may lead to the emergence of adult mosquitoes with greater fitness, causing an overall positive effect on Ae. aegypti population growth rates.

Insecticidal and repellent activity of native and exotic lemongrass on Maize weevil.

Corn crop, due to its easy adaptation to the most diverse agroecosystems, spreads throughout the different regions of the world, making it one of the most important agricultural crops. In this crop, pest insects stand out for causing losses both in the field and in warehouses. The application of essential oils can be an important technique to be investigated in the management of insects due to its known insecticidal activity and low risk to the environment. The objective of the work was to value the insecticide and repellent effect of essential oils of exotic lemongrass (Cymbopogon citratus) and native lemongrass (Elionurus sp.) for the management of maize weevil (Sitophilus zeamais (Mots., 1855, Coleoptera: Curculionidae)). The chemical analysis of the oils made by CG-MS showed that the chemical composition of the native and exotic lemongrass is similar, however, the exotic species presented a greater number of compounds. The essential oils of native and exotic lemon grass have efficiency on maize weevil mortality, and it is verified that the increase in the applied dose reflects in a reduction in the insect's exposure time for death to occur. The essential oil of both species showed repellent capacity at all times evaluated. Thus, it can be said that both species have the capacity and potential to be used in the management of corn weevil, and can be an alternative for smallhorders farmers and organic production.

Antioxidant activity, antibacterial and inhibitory effect of intestinal disaccharidases of extracts obtained from Eugenia uniflora L. Seeds.

The use of medicinal plants for disease prevention, treatment and cure is an ancient practice used by humanity, and many plants species are used in bioprospecting research. In this context, its stands out Eugenia uniflora L., populary known as pitangueira and belongs to the Myrtaceae family, with a wide geographic distribution and native of Brazil. In view of the therapeutic qualities of the plant and the lack of the studies on its seeds, the present study had as objective to evaluate the phytochemical profile of the extracts of Eugenia uniflora L. seeds, from different solvents, as well as their antibacterial activity, antioxidant and its inhibitory effect of intestinal disaccharidases. Results showed a high content of phenolic compounds and total flavonoids, thus characterizing antioxidant activity, also highlighting the best bacteriostatic action for the Gram positive strain of Staphylococcus aureus in the ethanolic fraction. Regarding the disaccharidases, a strong inhibitory action was observed for all concentrations, evidencing a antihyperglycemic potential. The present research allowed to concluded that Eugenia uniflora L. seeds have promising biological activities for the industrial sector, but a more detailed investigation is needed regarding their bioactive compounds.

Antioxidant activity, antibacterial and inhibitory effect of intestinal disaccharidases of extracts obtained from Eugenia uniflora L. seeds / Atividade antioxidante, antibacteriana e efeito inibidor de dissacaridases intestinais de extratos obtidos das sementes de Eugenia uniflora L

The use of medicinal plants for disease prevention, treatment and cure is an ancient practice used by humanity, and many plants species are used in bioprospecting research. In this context, its stands out Eugenia uniflora L., populary known as pitangueira and belongs to the Myrtaceae family, with a wide geographic distribution and native of Brazil. In view of the therapeutic qualities of the plant and the lack of the studies on its seeds, the present study had as objective to evaluate the phytochemical profile of the extracts of Eugenia uniflora L. seeds, from different solvents, as well as their antibacterial activity, antioxidant and its inhibitory effect of intestinal disaccharidases. Results showed a high content of phenolic compounds and total flavonoids, thus characterizing antioxidant activity, also highlighting the best bacteriostatic action for the Gram positive strain of Staphylococcus aureus in the ethanolic fraction. Regarding the disaccharidases, a strong inhibitory action was observed for all concentrations, evidencing a antihyperglycemic potential. The present research allowed to concluded that Eugenia uniflora L. seeds have promising biological activities for the industrial sector, but a more detailed investigation is needed regarding their bioactive compounds.

A utilização de plantas com fins medicinais para prevenção, tratamento e cura de doenças é uma prática antiga utilizada pela humanidade, sendo que muitas espécies vegetais são usadas para a pesquisa da bioprospecção. Neste contexto, destaca-se a Eugenia uniflora L., conhecida popularmente como pitangueira e pertencente à família Myrtaceae, com ampla distribuição geográfica e nativa do Brasil. Diante das qualidades terapêuticas da planta e a falta de estudos sobre suas sementes, o presente trabalho teve como objetivo avaliar o perfil fitoquímico dos extratos das sementes de Eugenia uniflora L. a partir de diferentes solventes, bem como sua atividade antibacteriana, antioxidante e seu efeito inibidor de dissacaridases intestinais. Os resultados mostraram um alto teor de compostos fenólicos e flavonóides totais, caracterizando a atividade antioxidante, destacando também a melhor ação bacteriostática para a cepa Gram positiva de Staphylococcus aureus na fração etanólica. Em relação às dissacaridases, uma forte ação inibitória foi observada para todas as concentrações, evidenciando um potencial anti-hiperglicêmico. A presente pesquisa permitiu concluir que as sementes de Eugenia uniflora L. apresentam atividades biológicas promissoras para o setor industrial, mas é necessária uma investigação mais detalhada de seus compostos bioativos.

Oviposition preferences of the mosquito Aedes aegypti Linnaeus, 1762 (Culicidae): an urban environment bioassay.

The establishment of an invasive species depends on reproductive success and dispersion capability in the new environment. One of the striking examples of invasion in urban environments is the mosquito Aedes aegypti Linnaeus, 1762 (Culicidae). The success of this species is primarily attributed to its ability to colonize urban environments, and some of the important adaptive strategies associated with this ability is the preference for humans as a blood source and intense occupation of residential (indoor) environments. This study evaluated the effects of location (indoor vs. outdoor) and water nutrient level (% organic matter) on the oviposition preference of A. aegypti in an urban environment. We used oviposition choice experiments to evaluate mosquito oviposition in containers holding 1:1 vs 1:0 ratios of water: organic matter placed indoors and outdoors. Eggs were sampled once per week for nine weeks. Our results revealed a strong oviposition preference for outdoor containers, with a significant preference for containers with higher concentrations of organic matter during the fifth to ninth weeks. However, mosquitoes occupying indoor environments did not prefer to lay eggs in containers with lower levels of organic matter. A better understanding of the preferences of A. aegypti regarding the nutrient level and location of oviposition containers can increase our understanding of the behavioral factors allowing mosquitoes to utilize anthropogenic environments.

Antioxidant activity, antibacterial and inhibitory effect of intestinal disaccharidases of extracts obtained from Eugenia uniflora L. Seeds

Abstract The use of medicinal plants for disease prevention, treatment and cure is an ancient practice used by humanity, and many plants species are used in bioprospecting research. In this context, its stands out Eugenia uniflora L., populary known as pitangueira and belongs to the Myrtaceae family, with a wide geographic distribution and native of Brazil. In view of the therapeutic qualities of the plant and the lack of the studies on its seeds, the present study had as objective to evaluate the phytochemical profile of the extracts of Eugenia uniflora L. seeds, from different solvents, as well as their antibacterial activity, antioxidant and its inhibitory effect of intestinal disaccharidases. Results showed a high content of phenolic compounds and total flavonoids, thus characterizing antioxidant activity, also highlighting the best bacteriostatic action for the Gram positive strain of Staphylococcus aureus in the ethanolic fraction. Regarding the disaccharidases, a strong inhibitory action was observed for all concentrations, evidencing a antihyperglycemic potential. The present research allowed to concluded that Eugenia uniflora L. seeds have promising biological activities for the industrial sector, but a more detailed investigation is needed regarding their bioactive compounds.

Resumo A utilização de plantas com fins medicinais para prevenção, tratamento e cura de doenças é uma prática antiga utilizada pela humanidade, sendo que muitas espécies vegetais são usadas para a pesquisa da bioprospecção. Neste contexto, destaca-se a Eugenia uniflora L., conhecida popularmente como pitangueira e pertencente à família Myrtaceae, com ampla distribuição geográfica e nativa do Brasil. Diante das qualidades terapêuticas da planta e a falta de estudos sobre suas sementes, o presente trabalho teve como objetivo avaliar o perfil fitoquímico dos extratos das sementes de Eugenia uniflora L. a partir de diferentes solventes, bem como sua atividade antibacteriana, antioxidante e seu efeito inibidor de dissacaridases intestinais. Os resultados mostraram um alto teor de compostos fenólicos e flavonóides totais, caracterizando a atividade antioxidante, destacando também a melhor ação bacteriostática para a cepa Gram positiva de Staphylococcus aureus na fração etanólica. Em relação às dissacaridases, uma forte ação inibitória foi observada para todas as concentrações, evidenciando um potencial anti-hiperglicêmico. A presente pesquisa permitiu concluir que as sementes de Eugenia uniflora L. apresentam atividades biológicas promissoras para o setor industrial, mas é necessária uma investigação mais detalhada de seus compostos bioativos.