Dillapiole in Piper holtonii as an Inhibitor of the Symbiotic Fungus Leucoagaricus gongylophorus of Leaf-Cutting Ants.

Plants of the Piperaceae family are studied for their diverse secondary metabolism with a vast array of compounds that act as chemical defense agents against herbivores. Of all the agricultural pests, the management of insects is a highly significant challenge in the Neotropics, and ants of the Attini tribe pose a major problem. Due to their symbiotic association with the fungus Leucoagaricus gongylophorus (Möller) Singer (Agaricaceae), the species of Atta and Acromyrmex have exhaustive foraging activity which has intensified as deforestation and monoculture farming have increased. The control of leaf-cutting ants is still carried out with synthetic products with negative consequences to the environment and human health. In search for natural and sustainable alternatives to synthetic pesticides, Piper holtonii C. DC. was selected among other plant species after field observations of the foraging activity of Atta cephalotes, which revealed that P. holtonii was never chosen by ants. In vitro evaluation of an ethanol extract of the leaves of P. holtonii resulted in promising inhibitory activity (IC50 102 ppm) against L. gongylophorus. Subsequently, bioassay-guided fractionation led to the isolation of the phenylpropanoid dillapiole, which was also detected in the essential oil. This compound demonstrated inhibition of the fungus with an IC50 of 38 ppm. Considering the symbiotic relationship between the Attini ants and L. gongylophorus, the negative effect on the survival of one of the organisms will affect the survival of the other, so dillapiole or standardized essential oil extracts of P. holtonii containing this active principle could be a unique and useful source as a control agent for leaf cutting-ants.

The effect of correspondence between descriptions of contingencies and contingencies on the conduct of election under the self-control paradigm / Efeito da correspondência entre descrições de contingências e contingências sobre o comportamento de escolha sob o paradigma de autocontrole / Efecto de la correspondencia entre descripciones de contingencias y contingencias sobre la conducta de elección bajo paradigma de autocontrol

Abstract In this paper, the effect of correspondence history between contingency and contingency descriptions on the behavior of choice under the self-control paradigm is analyzed in 85 participants between the ages of 10 and 11, through two intrasubject experiments, one carried out in a laboratory context and another in a simulated natural situation. The results indicate that it is possible to affect the behavior of choice between an immediate reinforcer of lesser magnitude and a delayed one of greater magnitude in favor of the second alternative, from an experimental history of correspondence between descriptions of contingencies and contingencies. In both experiments, most of participants chose the delayed reinforcer after undergoing correspondence tests between descriptions and contingencies, and the immediate reinforcer after facing the correspondence absent trials, even though the training situations were formally and functionally different in relation with the task established to evaluate the conduct of choice. The results are analyzed in light of the "Relational Frame Theory", specifically, in relation with the alteration of the functions of the language.

Resumo Neste trabalho, analisa-se o efeito da história de correspondência entre as descrições de contingências e contingências sobre o comportamento de escolha sob o paradigma de autocontrole com 85 participantes entre 10 e 11 anos de idade, por meio de duas experiências intrassujeito, uma realizada em contexto de laboratório, e outra, numa situação natural simulada. Os resultados indicam que é possível afetar o comportamento de escolha entre um reforçador imediato -de menor magnitude- e outro demorado -de maior proporção- em favor da segunda alternativa a partir de uma história experimental de correspondência entre as descrições de contingências e contingências. Em ambas as experiências, a maioria de participantes escolheu o reforçador demorado depois de experimentar os ensaios de correspondência entre descrições e contingências, e o reforçador imediato depois de enfrentar os ensaios de correspondência ausente, embora as situações de treinamento tenham sido formal e funcionalmente diferentes com relação à tarefa estabelecida para avaliar o comportamento de escolha. Os resultados foram analisados à luz da Teoria das Molduras Relacionais, especificamente quanto à alteração das funções da linguagem.

Resumen En este trabajo se analiza el efecto de la historia de correspondencia entre las descripciones de contingencias y las contingencias sobre la conducta de elección bajo paradigma de autocontrol en 85 participantes de entre 10 y 11 años de edad, por medio de dos experimentos intrasujeto, uno realizado en contexto de laboratorio y otro en una situación natural simulada. Los resultados indican que es posible afectar la conducta de elección entre un reforzador inmediato -de menor magnitud- y otro demorado -de mayor proporción- en favor de la segunda alternativa a partir de una historia experimental de correspondencia entre las descripciones de contingencias y las contingencias. En ambos experimentos, la mayoría de participantes eligió el reforzador demorado después de experimentar los ensayos de correspondencia entre descripciones y contingencias, y el reforzador inmediato después de enfrentar los ensayos de correspondencia ausente pese a que las situaciones de entrenamiento fueron formal y funcionalmente diferentes en relación con la tarea establecida para evaluar la conducta de elección. Los resultados se analizan a la luz de la Teoría de los Marcos Relaciónales, específicamente en relación con la alteración de las funciones del lenguaje.

Conducta de elección bajo paradigma de autocontrol y desempeño académico en una situación grupal / Choice behavior under self-control paradigm and academic performance in a group situation

El objetivo del presente estudio fue establecer la relación entre autocontrol y las variables: desempeño académico, grado escolar y sexo en 87 estudiantes de transición, segundo y cuarto grado de primaria. Para medir la variable autocontrol, se planteó una tarea de elección entre un reforzador inmediato de baja magnitud y un reforzador postergado de mayor proporción. Esta tarea se presentó de forma grupal simulando los eventos de elección que se presentan en la realidad. Los resultados indican que las variables desempeño académico y grado escolar se relacionaron de manera positiva con autocontrol, mostrando diferencias estadísticamente significativas. Adicionalmente se encontró que en términos de proporción las mujeres tienden a postergar el refuerzo en mayor medida en comparación con los hombres.

The aim of this article was to establish the relation between self-control and a group of variables: academic performance, grade and gender, in 87 students of transition, second and fourth grade. To measure self-control, it was selected an election task between a delayed reinforcer and an immediate reinforce. This task was presented in a group activity simulating real election events. The results indicate that the academic performance and grade variables were associated positively with self-control, indicating statistically significant differences. In addition it was observed that women tend to delay the reinforcement at higher rates than men do.