Abstract
Sandflies are holometabolous insects that are of great epidemiological importance in the neotropical region as vectors of leishmaniases. Caves are ecotopes that significantly differ from external environments and, among the insects that live or visit their internal area and adjacent environment, sandflies are commonly found. Based on this context, the objective of this work was to examine the period of activity of sandflies in the cave environment in the aphotic zone. Thus, four sandfly captures were conducted, one in each season of the year, in a cave where studies on the bioecological aspects of sandfly fauna have been conducted since 2008. In this same study, we have also noticed the presence of flagellates in some captured females. Catches were carried out for 24 hours using a Shannon trap, light bait, and cave walls were actively searched. We collected a total of 638 sandflies, representing 11 species. The most abundant species and with more intense period of activity were, in descending order: Lu. cavernicola (62%), Ev. spelunca (16%) and Ev. sallesi (14%). A total of 69 females were dissected to check for natural infection, and in five specimens we found living flagellated forms: two Ev. spelunca, two Ev. sallesi and one Sc. sordellii. This study shows that the activity of some species caught in the aphotic zone of the cave, especially Lu. cavernicola, differs from what has already been reported in previous sandfly captures, which are almost always conducted at night and during twilight. The existence of sandflies that were naturally infected with flagellates and the lack of awareness regarding the behaviour of sandflies in cave environments are strong indicators of the need for further study on this group of insects in this ecotope, as a safety measure to protect the visitors of such environment.
Highlights
Leishmaniasis is a complex infectious disease caused by protozoan parasites of the morphologically homologous genus Leishmania Ross, 1903 (Kinetoplastida: Trypanosomatidae), all with varying degrees of specificity to invertebrate host [1]
The following parameters were taken into account: a photoperiod with a light/dark cycle (LD) 12:12, observed in the external environment, and peak activity of sandflies in all seasons during scotophase (18:00–5:00)
Caves are considered stable environments when compared to epigean habitats and are characterized by a permanent lack of light far from entrances [3,15]. Fauna adapted to these conditions can be classified according to their level of adaptation: troglobites, troglophiles and trogloxenes [16]
Summary
Leishmaniasis is a complex infectious disease caused by protozoan parasites of the morphologically homologous genus Leishmania Ross, 1903 (Kinetoplastida: Trypanosomatidae), all with varying degrees of specificity to invertebrate host [1]. The main form of parasite transmission to humans and other mammalian hosts is through the bite of female flies of the family Psychodidae, subfamily Phlebotominae, popularly known as sandflies. The occurrence of this parasite in a given area depends primarily on the putative presence of the vector and a host/reservoir [2]. The caves are considered stable and peculiar environments that are important for the balance of ecosystems, since inside, the microclimate shows little variation of these factors. Caves are relatively more isolated than others ecosystems, with specific physical and constant environment, their fauna and flora present peculiar aspects. With more than 600 species that have already been classified, the cave fauna of Brazil is the richest in South America [4]
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