O Ritmo circadiano difere entre machos e fêmeas de flebotomíneos Nyssomyia whitmani (Diptera: Psychodidae) independentemente de variações climáticas

Abstract

This research had the main purpose of determining the Nyssomyia’s circadian rhythm when it comes to its antropophilic activities and its relation to abiotic factors on a forest fragment located near to Dourados, Mato Grosso do Sul, Brazil. The collecting of the data was developed with monthly captures of 25 uninterrupted hours made with the black, modified, Shannon trap, having the manual assistance of electric vacuums, with two individuals aspirating at the same time. We captured a total of 8.3633 sandflies belonging to the Nyssomyia whtmani specie, with 5.975 of them being male and 2.388 being female. The frequency of days in which the number of males was superior to the number of females doesn’t differ from what was expected then (p > 0,05). The sandflies were submitted to a covariance analysis with data about the temperature and air humidity obtained during the capture period. Our results point out that none of these factors influenced in the capturing of adults, for the male as much as for the females. The capturing of sandflies was larger during the period of scotophase, and the largest capture density occurred between 17 hours pm and 2 hours am, showing its peak between 23 hours pm and 01 hour am. During the photophase period the density of sandflies was low, totalizing only 5% of the insects, most of them having being captured between 10 hours am and 11 hours am. Nyssomyia whitmani is a complex of criptical species, being one of the main within the American cutaneous leishmaniosis transmission chain and it is widely distributed in Brazil as well as in many countries of the Southern Mato Grosso do Sul, which demonstrates the importance of investigating the populations of this species in order to obtain the knowledge on its behavior in different parts of the country.