PHYSIOLOGICAL AGE IN LUTZOMYIA-YOUNGI (DIPTERA, PSYCHODIDAE) POPULATIONS FROM AN ENDEMIC AREA FOR CUTANEOUS LEISHMANIASIS, VENEZUELA

Batches of sylvatic females of Lutzomyia youngi (Phlebotominae) captur ed in a Shannon trap on twelve occasions over one year in a locality w here subcutaneous leishmaniasis is endemic, near the city of Trujillo, Venezuela, were used to study: 1) the percentages of parous females a ccording to previously established criteria and 2) the average number of eggs laid spontaneously by isolated females during 7 days after fee ding on hamsters. The data on the batches of females captured on night s previous to the rainy period (prepluvial) were compared with those o n females captured after the rains (postpluvial). Significant differen ces were detected by variation analysis for two variables and differen t number of N, as also were consistent groupings by Duncan's Test for pre-and postpluvial lots of females. The females captured on nights pr ior to the rainy periods (January-March and August-September) presente d higherrates 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 occurre d 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.