Establecimiento, mantenimiento y productividad de una colonia de laboratorio de Lutzomyia spinicrassa Morales, Osorno-Mesa, Osorno y Hoyos, 1969 (Diptera: Psychodidae) en Colombia

El flebótomo Lutzomyia spinicrassa es vector de Leishmania braziliensis y tiene amplia distribución en plantaciones de café en Colombia y Venezuela. Metodología: Se estableció una colonia en condiciones de laboratorio a partir de 600 hembras de L. spinicrassa capturadas en el campo y mantenidas a temperatura de 23º C y humedad relativa de 70%. El tiempo de desarrollo desde huevo hasta adulto osciló entre 58 y 78 días, en promedio 11 semanas. Se compararon parámetros poblacionales de la especie obtenidos a partir de cinco generaciones sucesivas mantenidas en grupos, con una generación criada individualmente. Resultados: Se obtuvieron los siguientes parámetros en cada condición experimental: tasa neta de reproducción (6,92 y 7 hembras por hembra por generación), tasa intrínseca de incremento poblacional (0,17 y 0,18 hembras por hembra por semana) y tasa finita de incremento poblacional (1,06 y 1,19 individuos por hembra por semana). Conclusión: Estos datos sugieren que la colonia de L. spinicrassa tuvo un incremento constante durante las seis generaciones analizadas.

Evaluation of the Toxic Effect from Eupatorium Microphyllum L.F. (Asteraceae) Extracts on Aedes Aegypti Larvae (Diptera: Culicidae) in Laboratory Conditions

In the present work the toxic activity of extracts of Eupatorium microphyllum L.F. was evaluated on 4th instar larvae of the mosquito Aedes aegypti (Linneaus), under laboratory conditions. Aqueous extracts were utilized in concentrations of 500 mg L-1, 1,500 mg L-1 and 2,500 mg L-1 and acetone in concentrations of 10 mg L-1, 20 mg L-1, 30 mg L-1, 40 mg L-1and 50 mg L-1. The bioassays were carried out for triplicate each one with 20 larvae, exposed for 24 hours to 150 mL of solution. In all the bioassays were employed control groups. In the evaluation of the acetone extracts, a negative control was employed to avoid that the mortality of the larvae to occur on account of the solvent. The Aqueous extracts showed low moderate action in the mortality of larvae, less than 20%. On the contrary, the action of the acetone extracts was observed to 10 and 20 mg L-1with 15% of mortality, while to 30 and 40 mg L-1 were registered 22 to 38% of mortality. However, to 50 mg L-1 the mortality was of 95.4% with highly significant statistical results. The concentrations of the acetone extracts showed to be the most efficient for the control of the mosquitoes selected. Both types of extracts showed toxic effect in larvae of A. aegypti, nevertheless, greater effect in the acetone extracts was observed relating to the aqueous extracts of E. microphyllum, which constitutes a viable alternative in the search of new larvicides from composed natural.

Las Jarretaderas, Nayarit, Mexico: a Social Interstice in Touristic Zona Metropolitana of Sun and Sand

The objective of the present article is to illustrate the social interstice (Las Jarretaderas) existing between the municipalities Bahía de Banderas, Nayarit and Puerto Vallarta, Jalisco. The researched community is an outstanding case-study providing an in-depth analysis of a number of social process mostly related to the chiapaneca migration. The text is divided into two sections. The first one deals with the urbanization process of the metropolitan area of Puerto Vallarta. The second and longer section defines the concept of social interstice and explains how the researched locality falls under under that previously-defined concept according to the processes analyzed.