Intraspecific variability of Triatoma dimidiata based on the analysis of its cuticular hydrocarbon pattern.

M PATRICIA JUAREZ; GUSTAVO M. CALDERÓN FERNÁNDEZ; JUAN R. GIROTTI

Reno, Nevada, USA

Congreso; IV International Congress of Vector Ecology; 2005

Society for Vector Ecology

INTRASPECIFIC VARIABILITY OF TRIATOMA DIMIDIATA BASED ON THE ANALYSIS OF ITS CUTICULAR HYDROCARBON PATTERN. Calderón Fernández, Gustavo; Juárez M. Patricia; Girotti, Juan; Instituto de Investigaciones Bioquímicas de La Plata (CONICET-UNLP), Facultad de Ciencias Médicas, calles 60 y 120, La Plata, 1900, Argentina. e-mail: mjuarez@isis.unlp.edu.ar   The instraspecific variability of Triatoma dimidiata (Hemiptera: Reduviidae: Triatominae), a relevant Chagas Disease vector in northern Latin America, was studied by comparing the cuticular hydrocarbon profile of specimens collected from several localities of Belice, Colombia, Costa Rica, Guatemala, Honduras and Mexico. The hydrocarbon composition was analyzed by capillary gas chromatography (CGC), and component structures were identified by CGC coupled to mass spectrometry (MS). Principal componet analysis as well as other multivariate procedures were applied on hydrocarbon relative abundance values, in order to establish the relationship and differentiation degree between populations under study. Hydrocarbon profiles showed a mixture of lineal and methyl-branched chains between 21 to more than 40 carbon atoms prevailing the odd-numbered components of 25 to 33 carbons. Analyses results showed that populations grouped basically in accordance to their geographical vicinity although some exceptions could be found. Specimens from Jutiapa and Santa Rosa (southern Guatemala), Honduras, Guanacaste, Heredia, San Jose and Cartago (Costa Rica) grouped togheter and so did those from Hidalgo, Veracruz, northern Oaxaca and Chiapas (Mexico). Insects from Peten (northern Guatemala) grouped with those from Yucatan and Cozumel (Mexico). But the specimens collected from the southern region of Oaxaca  were cleary differentiated from those of the northern Oaxaca and the neighboring state of Chiapas. Colombian specimens were closely grouped with those from the eastern region of Mexico whereas insects from Lanquin caves (central Guatemala) and Belice showed a very different hydrocarbon pattern that greatly separated them from the other populations. We can conclude that T. dimidiata possesses a large overall variability. We can also conclude that human migrations played an important role in its dispersion.