RESUMEN
Siparuna guianensis (Laurales: Siparunaceae) has a terpene-rich essential oil with great potential for larvicides. The poor water miscibility of their compounds makes nano-emulsions of great interest for novel bioactive systems, including for control of Aedes aegypti (Diptera: Culicidae). This species is adapted to urban environments with important role in the epidemiology of some arboviruses such as dengue, chikungunya fever, zika, and urban yellow fever. The aim of the present study was to evaluate the feasibility of nano-emulsification to affect Ae. aegypti larvae. An optimal system was achieved by using a nonionic single surfactant, highlighted by its satisfactory size distribution profile. Moreover, improved larvicidal activity in comparison to bulk essential oil can be observed for the nano-emulsions. The estimated LC50 and LC90 values after 24 h of treatment of larvae with the essential oil were, respectively, 86.5232 and 134.814 µg/ml, while the estimated LC50 and LC90 value after treatment with the nano-emulsion were 24.7572 and 75.2452 µg/ml, respectively. The utilization of a simple technique to produce a fine nano-emulsion opens perspective for further integrative practices of mosquito control and giving value to this Amazon plant species may encourage its sustainable use and contribute to conservation policies.
Asunto(s)
Aedes , Insecticidas/análisis , Laurales/química , Aceites Volátiles/química , Animales , Formas de Dosificación , Dosificación Letal Mediana , Nanoestructuras , Aceites Volátiles/administración & dosificaciónRESUMEN
This study provides the first data on the population structure of swimming crab Callinectes ornatus Ordway, 1863 bycatch from coastal shrimp fishing in northern Rio de Janeiro State, Brazil (21º 30'-21º 50' S and 41º 05'-41º 07' W). Crabs were collected monthly from April 2006 to March 2007. A total of 5,611 specimens were analyzed, of which 3,951 were males and 1,660 ovigerous and non-ovigerous females. The overall sex ratio (2:1) differ significantly from the expected 1:1 proportion, being the mature males significantly predominant as bycatch in this fishery. The specimens' carapace width and weight varied from 27 to 126 mm (mean: 77.3 ± 12.3 mm) and 1.2 to 128.2 g (mean: 31.0 ± 14.4 g) for males, and 30 to 101 mm (mean: 63.4 ± 9.3 mm) and 1.7 to 66.0 g (mean: 16.4 ± 7.4 g) for ovigerous and non-ovigerous females. Seasonal comparisons did not reveal differences between the number of specimens captured in dry and rainy periods considering both sexes and maturity stages. The size at first maturity was 79 mm for males and 65 mm for females, and the carapace width-weight relationship indicated an alometric pattern for both sexes. The bycatch swimming crabs are locally used as bait, but the capture tendency for a specific sex/age-group can affect this population structure over time.
Este estudo fornece os primeiros dados sobre a estrutura populacional do siri Callinectes ornatus Ordway, 1863 capturado incidentalmente através da pesca camaroneira realizada no litoral norte do estado do Rio de Janeiro, Brasil (21º 30'-21º50' S e 41º 05'-41º 07' O). Os siris foram coletados mensalmente entre abril de 2006 a março de 2007. Um total de 5.611 espécimes foram analisados, dos quais 3.951 eram do sexo masculino e 1.660 fêmeas ovígeras e não ovígeras. A razão sexual (2:1) diferiu significativamente da proporção 1:1 esperada, sendo os machos maduros significativamente predominantes como captura incidental nesta pescaria. A largura da carapaça e o peso dos espécimes variaram de 27 a 126 mm (média: 77,3 ± 12,3 mm) e 1,2 a 128,2 g (média: 31,0 ± 14,4 g ) para machos, e 30 a 101 mm (média: 63,4 ± 9,3 mm ) e 1,7 a 66,0 g (média: 16,4 ± 7,4 g) para fêmeas ovígeras e não ovígeras. As comparações sazonais não revelaram diferenças entre o número de espécimes capturados nos períodos seco e chuvoso, considerando ambos os sexos e estágios de maturidade. O tamanho de primeira maturação foi de 79 mm para machos e 65 mm para as fêmeas, e a relação largura da carapaça-peso indicou padrão alométrico para ambos os sexos. Os siris capturados incidentalmente são utilizados localmente como isca, mas a tendência de captura sobre um grupo sexual/etário específico pode afetar a estrutura dessa população ao longo do tempo.
