ABSTRACT
ABSTRACT Several studies have shown that the survival and reproduction of lacewings varies depending on the type of prey they consumed, especially during the first instar. In this study, we evaluated the effect of a diet consisting of Ephestia kuehniella (EK) and/or Planococcus-citri (PC) eggs offered to first instar Chrysoperla externa on subsequent development and survival. Larvae supplied only with P. citri (PC) nymphs had extended immature development, low survival, adults with lower weight and longevity, low fecundity and egg viability, and lower net reproduction rate (R0). Larvae submitted to the treatment EK+PC responded positively to the diet, showing results similar to those obtained in the control-EK treatment. Therefore, this mealybug supports suitable development and reproduction of C. externa when it is provided to second instar larvae after they fed on E. kuehniella eggs as first instars. As far as we know, this is the first report that demonstrates the effect of natural prey and alternatives on different larval stages of lacewings. This information is valuable in developing protocols for use of C. externaas a pest control agent.
ABSTRACT
ABSTRACT This study aimed to determine the consumption of Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) nymphs and the predator:prey ratio required for high predatory efficacy and survival of Chrysoperla externa (Hagen, 1861) (Neuroptera: Chrysopidae) larvae under different densities of prey, reared in rose bushes. Consumption by first-, second-, and third-instar larvae of C. externa was assessed. The predatory efficiency and survival of the predator were calculated for larvae in the second instar under densities of 20, 40, 80, 120, and 160 nymphs of P. citri and predator:prey ratios of 1:5, 1:10, and 1:20. The assessments were performed after 24 and 48 hours of exposure between species. There was increasing consumption throughout the larval development of C. externa. The predator:prey ratios 1:5 and 1:10 were the most efficient for P. citri population reduction, but the 1:5 ratio led to lower survival of larvae than the 1:10 and 1:20 ratios. There was a positive correlation between C. externa larval density and cannibalism (ρ = 0.45) and a negative correlation between predator density and P. citri population density (ρ = -0.81). Third-instar larvae consume more P. citri nymphs than second-instar larvae. Second-instar larvae of this lacewing released at a 1:20 ratio caused total mortality of mealybug nymphs within 48 hours, regardless the density of P. citri, with high larvae survival of C. externa.
ABSTRACT
In this paper we screened the dichloromethane extract from the aerial parts of Salvia officinalis L., Lamiaceae, against a representative panel of microorganisms that cause caries, conducted a bioassay-guided fractionation to establish themselves the most active metabolite (manool) and determined the Salvia officinalis fraction with the manool highest concentration to be used to activate an ingredient in oral care products such as toothpastes and mouthwashes. Both manool and S. officinalis extract showed very promising minimal inhibitory concentration values (between 6.24 and 31.36 µg.ml-1) and time kill curves against the primary causative agents of dental caries (Streptococcus mutans) revealed that, at twice its minimal bactericidal concentration (12.48 µg.ml-1), manool required 6 h to completely kill the bacteria. Salvia officinalis extract at twice its minimal bactericidal concentration (31.36 µg.ml-1 ) needed 12 h. The results achieved with Salvia officinalis extract motivated us to develop and validate an analytical RP-HPLC method to detect and determine manool in this extract. The validation parameters were satisfactorily met and evaluated allows us to consider the developed method suitable for use in different labs. In conclusion, our results evidenced that the manool-rich S. officinalis extract can be considered an analytically validated alternative to develop novel and effective antimicrobial agents against the main bacteria responsible for dental caries.
ABSTRACT
O estudo do comportamento em sociedades foi relegado por quase 50 anos, apesar das reiteradas propostas de Skinner considerando sua importância. No ano de 1980, Sigrid Glenn criou o conceito de metacontingência que contribui como uma importante ferramenta para a descrição e análise do comportamento social. Neste artigo são apresentados alguns estudos envolvendo metacontingências e discute-se o papel do analista do comportamento no desenvolvimento de temas que abordam questões sociais, incluindo análise e modificação de práticas culturais.