RESUMO

The study of insect reproduction is important from both basic and applied perspectives, particularly in mealybugs (Hemiptera: Pseudococcidae), because of the diversity of reproduction modes and also because they are important agricultural pests. Sex pheromone control strategies are currently being developed for many species. Pseudococcus calceolariae (Maskell) and Pseudococcus longispinus (Targioni Tozzetti) are closely related species that often coexist in the same host plant. In this study, mating behavior, the possible occurrence of asexual reproduction, and hybridization between them were investigated. We confirmed that both species did not show asexual reproduction and required the presence of a male to reproduce. When couples of the same species were put together, males had a highly stereotyped mating behavior, and females showed an active role in mating success by accepting or rejecting males with abdominal movements. In hybridization trials, no progeny was obtained for any of the interspecific combinations. Moreover, in interspecific pairs, males mainly moved randomly in the arena without direct contact with females and females showed no willingness to mate, escape, or not move in the presence of the male. Therefore, courtship and copulation success in both species were directly related to the specificity of the mating pair and, there was no evidence of hybridization. This information is useful for the understanding of reproduction in this family and supports the development of management techniques based on sex pheromones to disrupt reproduction or to monitor these mealybug species populations.

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RESUMO

The leafroller Proeulia auraria (Clarke) (Lepidoptera: Tortricidae) is a native, polyphagous, and growing pest of several fruit crops in Chile; it also has quarantine importance to several markets, thus tools for management are needed. Using synthetic pheromone compounds, we conducted field trials to optimize the blend for monitoring, and to determine the activity period of rubber septa aged under field conditions. We concluded that septa loaded with 200 µg of E11-14:OAc + 60 µg E11-14:OH allowed for efficient trap captures for up to 10 weeks. Using this blend, we studied the phenology of adult males in vineyards, apple, and blueberry orchards, identifying two long flight cycles per season, lasting from September to May and suggesting 2-3 generations during the season. No or low adult activity was observed during January and between late May and late August. Furthermore, mating disruption (MD) field trials showed that application of 250 pheromone point sources using the dispenser wax matrix SPLAT (Specialized Pheromone and Lure Application Technology, 10.5% pheromone) with a total of 78 g/ha of the blend described above resulted in trap shutdown immediately after application, and mating disruption >99% in all orchards for at least 5 months. We concluded that MD is feasible for P. auraria, needing now the development of a commercial product and the strategy (and protocols) necessary to control this pest in conventional and organic orchards in Chile. As far as we know, this is the first report on MD development against a South American tortricid pest.

RESUMO

Pseudococcus calceolariae, the citrophilous mealybug, is a species of economic importance. Mating disruption (MD) is a potential control tool. During 2017-2020, trials were conducted to evaluate the potential of P. calceolariae MD in an apple and a tangerine orchard. Two pheromone doses, 6.32 g/ha (2017-2018) and 9.45 g/ha (2019-2020), were tested. The intermediate season (2018-2019) was evaluated without pheromone renewal to study the persistence of the pheromone effect. Male captures in pheromone traps, mealybug population/plant, percentage of infested fruit at harvest and mating disruption index (MDI) were recorded regularly. In both orchards, in the first season, male captures were significantly lower in MD plots compared to control plots, with an MDI > 94% in the first month after pheromone deployment. During the second season, significantly lower male captures in MD plots were still observed, with an average MDI of 80%. At the third season, male captures were again significant lower in MD than control plots shortly after pheromone applications. In both orchards, population by visual inspection and infested fruits were very low, without differences between MD and control plots. These results show the potential use of mating disruption for the control of P. calceolariae.

RESUMO

The dorsal (DH) and ventral (VH) subregions of the hippocampus are involved in contextual fear conditioning. However, it is still unknown whether these two brain areas also play a role in defensive behavior induced by electrical stimulation of the dorsal periaqueductal gray (dPAG). In the present study, rats were implanted with electrodes into the dPAG to determine freezing and escape response thresholds after sham or bilateral electrolytic lesions of the DH or VH. The duration of freezing behavior that outlasted electrical stimulation of the dPAG was also measured. The next day, these animals were subjected to contextual fear conditioning using footshock as an unconditioned stimulus. Electrolytic lesions of the DH and VH impaired contextual fear conditioning. Only VH lesions disrupted conditioned freezing immediately after footshock and increased the thresholds of aversive freezing and escape responses to dPAG electrical stimulation. Neither DH nor VH lesions disrupted post-dPAG stimulation freezing. These results indicate that the VH but not DH plays an important role in aversively defensive behavior induced by dPAG electrical stimulation. Interpretations of these findings should be made with caution because of the fact that a non-fiber-sparing lesion method was employed.

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RESUMO

En este artículo se presentan dos casos de pacientes con el síndrome de Charles-Bonnet, entidad que tiende a ser subdiagnosticada en el ámbito de la salud, dada su rareza y desconocimiento por parte del personal médico. A partir de estos casos se presentan las características clínicas del síndrome y se brindan pautas para tener en cuenta en la fisiopatología, evaluación clínica, factores de riesgo, diagnóstico diferencial y tratamiento.

In this paper two cases of patients with Charles Bonnet syndrome are presented. This entity tends to be subdiagnosed in the scope of the health, giving to its peculiarity and ignorance on the part of the medical personnel. From these cases the clinical characteristics of the syndrome shows and guidelines offer to consider the physiopathology, clinical evaluation, risk factors, differential diagnosis and treatment.

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