Ultrastructure of the Antennae and Sensilla of Nyssomyia intermedia (Diptera: Psychodidae), Vector of American Cutaneous Leishmaniasis

Abstract

The antennal sensilla and the antenna of females Nyssomyia intermedia, one of the main vectors of American cutaneous leishmaniasis, were studied by scanning electron microscopy. The main goal was to characterize the quantity, typology, and topography of the sensilla with particular attention to the olfactory types. The insects were captured in the city of Corte de Pedra, State of Bahia, Brazil, by CDC-type light traps and raised in a laboratory as a new colony. Fourteen well-differentiated sensilla were identified, among six cuticular types: trichoidea, campaniformia, squamiformia, basiconica, chaetica, and coeloconica. Of these, six sensilla were classified as olfactory sensilla due to their specific morphological features. Smaller noninnervated pilosities of microtrichiae type were also evidenced by covering all antennal segments. The antennal segments differ in shapes and sizes, and the amount and distribution of types and subtypes of sensilla. This study may foment future taxonomic and phylogenetic analysis for a better evolutionary understanding of the sand flies. Besides, it may assist the targeting of future electrophysiological studies by Single Sensillum Recording, and aim to develop alternative measures of monitoring and control of this vector.

Ultrastructural comparison and distribution of sensilla on male and female antennae of the sand fly Phlebotomus papatasi (Diptera: Psychodidae): the vector of cutaneous leishmaniasis in Egypt

“…In the present study, the shape and number of the antennal segments of the males and females P. papatasi coincide with the previously described in the New World sand flies: males and females of Lutzomyia longipalpis (Fernandes et al, 2008); the females of Nyssomyia intermedia (Fernandes et al, 2020) and Old World sand flies: Ilango (2000) in female P. argentipes; and Bahia et al (2021) in females P. duboscqi. Few studies were available in literature on the antennae of male sand flies.…”

“…The sensillary classification were performed according to the descriptions of morphological types illustrated in specialized literature. To classify sensillary types, we adopted the nomenclature originally developed by researchers in insect sense organs (e.g., McIver, 1982;Zacharuk, 1985;Hallberg & Hansson, 1999) and updated for the sensory subtypes by Fernandes et al (2020). The general aspects of the antennal segments of P. papatasi as well as the typology and distribution of antennal sensilla have been documented by SEM and discussed with the previous studies carried out on P. papatasi (Jobling, 1987;Quate, 1964;Zayed et al, 2002a) and other sand fly species (Ilango, 2000;Zayed et al, 2002aZayed et al, , 2002bFernandes et al, 2008;Fernandes et al, 2020;Bahia et al, 2021).…”

“…The basiconic sensilla were observed as small little fingers in female P. duboscqi (Bahia et al, 2021) a closely related species to P. papatasi. The morphological functional classification of these sensilla was considered olfactory (Fernandes et al, 2020).…”

“…Antennae of phlebotomine sand flies are small in size and densely covered with pilosities and bristles which renders measuring the odor response difficult (Fernandes et al, 2008). Observations on the antennal sensilla using SEM were considered necessary before carrying out electrophysiological studies because they enable precise introduction of electrode to detect olfactory stimuli in insects (Fernandes et al, 2020). Olfaction in insects is important for survival, reproduction, and communication with conspecifics.…”

Morphological aspects of immature stages of Migonemyia migonei (Diptera: Psychodidae, Phlebotominae), an important vector of Leishmaniosis in South America, described by scanning electron microscopy

“…Trichoid sensilla of various subtypes are the most common type of sensilla found on larval and adult phlebotomine sand flies and other Diptera [ 7 , 39 , 40 ]. Mg .…”