Identification of Mosquitoes of Anopheles gambiae Species Complex A and B by Analysis of Cuticular Components

Abstract

Two important vectors of malaria in Africa, Anopheles gambiae and Anopheles arabiensis (Diptera: Culicidae), often occur sympatrically and cannot be distinguished morphologically. A chemical method was developed to identify individual laboratory-reared adult males or females of either species by extraction and analysis of cuticular components with gas chromatography. Statistically significant differences were seen between species when selected pairs of peaks were compared.

Gas chromatography/mass spectrometry analysis of the cuticular hydrocarbons from parasitic wasps of the genus Muscidifurax

“…Insects were dried and frozen prior to lipid extraction with hexane. Twenty insects of each sex and species (identified previously by morphological characters) were soaked in hexane for approximately 2 h. The hexane fraction was placed on a silica gel column; the first 3 mL was eluted off the column with additional hexane and collected [15]. Nonhydrocarbon lipids remained on the column and were discarded.…”

“…Additionally, CHCs have been used to differentiate species of beetles [14], mosquitoes [15], cockroaches [16], grasshoppers [17,18], termites [19,20], bees [21,22], fruit flies [23], tsetse flies [11][12][13]24], and others. The identification of CHCs by gas chromatography/mass spectrometry (GC/MS) allows the differentiation of four species of Muscidifurax by examining not only the gas chromatograms but also the mass spectra which clearly contain different compounds that demonstrate the sexual dimorphism in this species.…”

Non-destructive Determination of Age and Species of Anopheles gambiae s.l. Using Near-infrared Spectroscopy

“…gambiae s.s. and An. arabiensis cuticular components exist, 49 and gas chromatography has been used to identify these two species with an accuracy of 90%. 50 Thus, differences in the cuticular hydrocarbons, along with the differences in water content, likely contribute to our classification models.…”

Hydrocarbon-Based Discrimination of Three North American Blattella Cockroach Species (Orthoptera: Blattellidae) Using Gas Chromatography

“…Thus, we perceived the need to develop a rapid and reliable method of identifying all life stages of these two species, as well as B. vaga Hebard, the third Blattella species found in North America. Previously, gas chromatography (GC) of cuticular hydrocarbons was used to identify specimens of morphologically indistinguishable members of species complexes, such as Anopheles gambiae A and B mosquitoes (Carlson & Service 1980) and populations of Africanized and European honey bees (Carlson & Bolten 1984). Phylogenetic relationships have been studied recently using chemical characters in other insects including mole crickets (Castner & Nation 1984), the Drosophila virilis group (Bartelt et al 1986), and Tribolium spp.…”

“…Individual specimens were submerged in 1 ml of n-hexane in small vials for 10-20 min. Hydrocarbons were separated from the extracted lipids using chromatography on minicolumns containing 1 cm of silica gel (60-200 mesh, J. T. Baker, Philadelphia, Pa.) packed into disposable glass pipets (Carlson & Service 1980, Carlson & Bolten 1984. Separation of unsaturated hydrocarbons was done using silver nitrate impregnated thin-layer plates (Carlson & Bolten 1984).…”