RESUMO
The yellow clam Mesodesma mactroides is a cool-water species that typifies sandy beaches of the Southwestern Atlantic Ocean (SAO), which embraces one of the strongest ocean warming hotspots. The region is influenced by the Rio de la Plata (RdlP), which represents a zoogeographic barrier that restricts its larval exchange. We investigated yellow clam larval connectivity patterns using an individual based model (IBM). The IBM combined outputs from a 3D hydrodynamic model with a clam submodel that considered salinity- and temperature-dependent mortality for the planktonic larvae. Connectivity across the RdlP estuary occurred only for larvae released in spring during a strong La Niña event. Mortality due to freshwater precluded larval transport across the RdlP, whereas larval mortality induced by warmer waters reduced connectivity, leading to self-recruitment in most areas. Warming acceleration in this hotspot could further restrict larval connectivity between populations in the SAO, with conservation implications for this threatened species.
Assuntos
Bivalves , Mudança Climática , Animais , Água Doce , Larva , Salinidade , América do SulRESUMO
Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.
Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.
Assuntos
Animais , Aedes , Momordica charantia , Inseticidas/farmacologia , Extratos Vegetais/farmacologia , Folhas de Planta , LarvaRESUMO
Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.
Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.
Assuntos
Aedes , Larvicidas/análise , Momordica charantia/efeitos dos fármacos , Momordica charantia/toxicidadeRESUMO
Abstract Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.
Resumo Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.
RESUMO
Mormodica charantia (Curcubitaceae) is a plant with great medicinal potential, also used as an alternative of mosquitoes control as demonstrated by previous studies. We evaluated the larvicidal activity of crude extracts of ethyl acetate, methanol and hexane from flowers and fruits of M. charantia against Aedes aegypti (Culicidae). Flowers and fruits were macerated in methanol, ethyl acetate and hexane. Bioassays were performed with application of the extracts at final concentrations of 1 - 200 µg/mL in the middle of the third instar larvae of A. aegypti (L3). The results showed high toxicity to ethyl acetate extracts from flowers and fruits at concentrations of 200 µg/mL and 100 µg/mL, with 97% and 87% of larvae mortality (L3), respectively. Hexane extract demonstrated low toxicity, while methanol extract exhibited 78% larval mortality. The data suggested that the ethyl acetate extracts of flowers and fruits of M. charantia can effectively contribute to larvicidal activity. In addition, purification of M. charantia extracts may lead to a promising larvicidal activity to control the A. aegypti population.(AU)
Mormodica charantia (Curcubitaceae) é uma planta com grande potencial medicinal, sendo também uma alternativa no controle de mosquitos conforme demonstrado por estudos prévios. Avaliou-se a atividade larvicida dos extratos brutos de acetato de etila, metanólico e hexânico das folhas, flores e frutos de M. charantia no Aedes aegypti (Culicidae). Folhas, flores e frutos foram macerados em metanol, acetato de etila e hexano. Os bioensaios foram realizados com aplicação dos extratos nas concentrações finais de 1-200 µg/mL no meio de criação das larvas de terceiro estádio de A. aegypti (L3). Os resultados obtidos apontaram alta toxicidade para os extratos de acetato de etila das flores e frutos nas concentrações de 200 µg/mL e 100 µg/mL com mortalidade em L3 de 96,7% e 87%, respectivamente. Baixa toxicidade para o extrato hexânico e o extrato metanólico apresentou mortalidade de 78% larval. Os dados sugerem que os extratos de acetato de etila das flores e frutos de M. charantia podem contribuir efetivamente para atividade larvicida no controle da população de A. aegypti.(AU)
Assuntos
Momordica charantia/efeitos dos fármacos , Momordica charantia/toxicidade , Larvicidas/análise , AedesRESUMO
Ochlerotatus albifasciatus (Macquart) (Diptera: Culicidae) larvae develop synchronously after rainfall events in ephemeral or temporary pools, where they occasionally attain very high abundance. The aims of the current study were to analyze the response of life history parameters such as daily larval mortality, time to pupation, and adult size of Oc. albifasciatus to increasing larval density under controlled conditions, and to analyze the relationships of daily larval mortality with density and environmental variables (drying rate, temperature, and season) in urban rain pools in Buenos Aires, Argentina. An exponential increase in mortality was observed at high larval densities under controlled conditions. Development times and adult size (wing length) differed between males and females, and were also affected by density. Development times extended for 0.36 d for each order of magnitude of increase in larval density, and wing length decreased 0.0021 mm per additional larva in 600 cm(2). Larval density in the field varied from <1 larva per square meter to nearly 1100 larvae per square meter. Daily larval mortality values in the field were variable (0.02-0.91), positively related to the drying rate, and exhibited seasonal differences. No significant relation with larval density or temperature was found in the field. It remains to be established whether the density-independent mortality observed in this study is a generalized pattern of Oc. albifasciatus populations in Buenos Aires Province or a pattern restricted only to urban habitats.
Assuntos
Ochlerotatus/crescimento & desenvolvimento , Animais , Argentina , Cidades , Ecossistema , Feminino , Larva/crescimento & desenvolvimento , Masculino , Densidade Demográfica , ÁguaRESUMO
Two studies were carried out in order to test the effects of neem tree extracts (Azadirachta indica A. Juss) on sheep bot fly larvae (Oestrus ovis L. Diptera: Oestridae). First, aqueous extracts from neem seeds (ASNE) at 0, 5 y 10% (w/v) concentrations were tested on larval mortality in vitro. In a second study, the effect of oral administration with neem seed meal (0, 100 y 200mg/kg) and neem leaves (1% of diet) on number of larvae found at necropsy and larval development was evaluated in experimentally O. ovis-infected sheep. Results in Experiment 1 showed a significant (P<0.05) effect of ASNE on time to L1 mortality in a dosis-dependent manner. In Experiment 2, oral administration of seeds or leaves did not affect the number of larvae found at necropsy of the sheep, but interfered with larval development and there was a tendency to reduce larval weight at the end of the infection period (55d).