Physiological age in Lutzomyia youngi (Diptera: Psychodidae) populations from an endemic area for cutaneous leishmaniasis, Venezuela

Abstract

Batches of sylvatic females of Lutzomyia youngi (Phlebotominae) captured in a Shannon trap on twelve occasions over one year in a locality where subcutaneous leishmaniasis is endemic, near the city of Trujillo, Venezuela, were used to study: 1) the percentages of parous females according to previously established criteria and 2) the average number of eggs laid spontaneously by isolated females during 7 days after feeding on hamsters. The data on the batches of females captured on nights previous to the rainy period (prepluvial) were compared with those on females captured after the rains (postpluvial) . Significant differences were detected by variation analysis for two variables and different number of N, as also were consistent groupings by Duncan's Test for pre-and postpluvial lots of females. The females captured on nights prior to the rainy periods (January-March and August-September) presented higher rates of nulliparity (86-72%) and contained or laid a greater number of eggs (71-67) than those captured after the rains (March-June and November-December) which presented lower rates of nulliparity (60-24%) and a smaller number of eggs (50-30). The rainfall peaks occurred in April and September-October, respectively. It is considered that these differences can be used by epidemiological studies as a means of estimating the physiological age of female populations of L. youngy.

Characteristics of the bological cycle of Lutzomyia evandroi Costa Lima & Antunes, 1936 (Diptera: Psychodidae) under experimental conditions

“…On this basis, maximum oviposition occurs in a period when there is humidity necessary for immature stage development in animal shelters, under rocks, inside caves, or in other natural shelters. Scorza and Oviedo (1994), in Venezuela, observed that maximum oviposition (60 or more eggs) occurred during the prepluvial period. Studies of longer duration are needed in order to establish a safe correlation between the different phases of the life cycle and climatic variations.…”

Efecto de toldillos tratados industrial o manualmente con insecticidas de larga duración, en el control vectorial de la leishmaniasis cutánea en la Región Subandina de Colombia

“…Esto pudo deberse a que las dilataciones foliculares se reabsorbieron rápidamente o a que estas no se formaron. A pesar de que algunos autores han podido distinguir dentro de las hembras paridas de flebótomos, a las hembras con más de un ciclo gonotrófico, esto es con más de una dilatación folicular (Ferro et al, 1995), también se ha reconocido la dificultad para hacer esta distinción (Ready & Lainson, 1984;Scorza & Oviedo, 1994). La aclaración sobre la validez de usar la formación de dilataciones foliculares para identificar hembras multíparas en L. longiflocosa se podrá hacer solo cuando se realice el seguimiento en laboratorio de los cambios en la estructura de las ovariolas en las de hembras de esta especie a lo largo de varios ciclos gonotróficos.…”