Fine Structure and Distribution Pattern of Antennal Sensilla of Lutzomyia longipalpis (Diptera: Psychodidae) Sand Flies

Abstract

The specific aims of this work were to examine the antennal sensilla of Lutzomyia longipalpis (Lutz & Neiva 1912) (Diptera: Psychodidae) adults and to characterize their typology and topography, with special attention to olfactory sensilla. The surfaces of the antennal segments of Lu. longipalpis males and females were studied by scanning electron microscopy (SEM). Lu. longipalpis used in the current study were obtained from a colony originating from Lapinha Cave, Minas Gerais state, Brazil. Microtrichiae and 11 subtypes of sensilla were observed and characterized according to the following categories: five subtypes of trichoid sensilla (short, medium, long blunt-tipped, long pointed-tipped, and apical), two coeloconic sensilla (grooved and praying hands), and campaniform, chaetic, basiconic, and squamiform sensilla. SEM analyses showed few differences between males and females in the typology, topography, and quantity of antennal sensilla described. The current study is the first to identify several categories of antennal sensilla of the genus Lutzomyia and their distribution patterns. The identification of these sensillar types may be important in planning future electrophysiological studies to develop alternative measures of control and monitoring of Lu. longipalpis.

Typology and distribution of antennal sensory organs of adults Haematobia irritans of the Midwest Region of Brazil

“…This subtle differences probably is due to the need to process different types of stimuli received during the life cycle, involved in mating and oviposition e.g. Differences between the antennal sensilla of males and females have been also noted in others Muscomorpha, as in "Fruit-fly" D. melanogaster (Shanbhag et al 1999), "American botfly" D. hominis , "New World Screwworm fly" C. hominivorax (Fernandes et al 2004), as well as in Nematocera, as in "Sand fly" Lutzomyia longipalpis (Lutz and Neiva, 1912) (Diptera: Psychodidae: Plebotominae) (Fernandes et al 2008). We believe that the observation of few differences between the distribution of sensillary types of males and females is due to the fact that both sexes of the "horn fly" have the same feeding habits, the same hosts, feeding mainly on bovine blood.…”

“…The specimens were then placed in saline in an ultrasound apparatus for 1h. After this, the samples were fixed overnight with 2.5% glutaraldehyde in 0.1M caccodylate buffer, pH 7.2, at room temperature and posfixed in 1% osmium tetroxide (Fernandes et al 2004(Fernandes et al , 2005(Fernandes et al , 2008. Afterwards, it was washed in buffer, and dehydrated in an increasing series of concentrations of ethanol, alternating the concentrations of alcohol at 6h intervals, using 100% ethanol three times.…”

“…There samples were mounted at different inclinations in order to allow the visualization of the entire external surface of the antennae, including its ventral part, which usually remain hidden over the ventral sulcus of the face of the fly, when in its natural position. The samples were then sputtered with platinum in K550X Sputter Coater (Quorum Emitech, Ashford, UK) to be analyze the samples in the JSM 5600 JEOL scanning electron microscope (Jeol Ltd., Tokyo, Japan), at an accelerating voltage of 5.0-25Kv (Fernandes et al 2004(Fernandes et al , 2008. In the ultrastructural analysis, the morpho-function types of H. irritans sensilla were classified according their cuticle morphology and observed by SEM (Mitchell et al 1999, Hallberg & Hansson 1999.…”

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

“…Scanning electron microscopy (SEM) enabled the characterization of morphological criteria of sensilla such as distribution, presence, and number. 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).…”

A new species of Trichomyia (Diptera: Psychodidae: Trichomyiinae) and report of antennal sensilla in adult

“…The presence of different types of antennal sensilla is well-documented in insects, but less information is particularly found in psychodid flies (Faucheux & Gibernau, 2011). Ilango (2000) and Fernandes et al (2008) described the sensilla for species of Phlebotominae of medical importance, and Faucheux & Gibernau (2011) described the sensilla of five species of Psychodinae, Psychodini of economic interest.…”