Insect Science (2016) 23, 720–727, DOI 10.1111/1744-7917.12222 ORIGINAL ARTICLE Olfactory response of Anastrepha striata (Diptera: Tephritidae) to guava and sweet orange volatiles Edvin Diaz-Santiz 1 , Julio C. Rojas 1 , Leopoldo Cruz-L ´ opez 1 , Emilio Hern ´ andez 2 and Edi A. Malo 1 1 Grupo de Ecolog´ ıa de Artr´ opodos y Manejo de plagas, El Colegio de la Frontera Sur (ECOSUR), Carretera Antiguo Aeropuerto km 2.5, Tapachula, Chiapas, CP 30700 and 2 Programa Moscafrut SAGARPA-IICA, Subdirecci ´ on de Desarrollo de M´ etodos, Camino a los Cacahotales S/N, Metapa de Dom´ ınguez, Chiapas, CP 30860, M ´ exico Abstract The behavioral responses of virgin and mated female Anastrepha striata Schiner (Diptera: Tephritidae) to guava (Psidium guajava L.) or sweet orange (Citrus sinensis L.) were evaluated separately using multilure traps in two-choice tests in field cages. The results showed that flies were more attracted to guava and sweet orange volatiles than to control (unbaited trap). The physiological state (virgin or mated) of females did not affect their attraction to the fruit volatiles. Combined analysis of gas chromatography coupled with electroantennography (GC-EAD) of volatile extracts of both fruits showed that 1 and 6 compounds from orange and guava, respectively elicited repeatable antennal responses from mated females. The EAD active compounds in guava volatile extracts were identified by gas chromatography-mass spectrometry (GC-MS) as ethyl butyrate, (Z)-3-hexenol, hexanol, ethyl hexanoate, hexyl acetate, and ethyl octanoate. Linalool was identified as the only antennal active compound in sweet orange extracts. In field cage tests, there were no significant differences between the number of mated flies captured by the traps baited with guava extracts and the number caught by traps baited with the 6-component blend that was formulated according to the relative proportions in the guava extracts. Similar results occurred when synthetic linalool was evaluated against orange extracts. From a practical point of view, the compounds identified in this study could be used for monitoring A. striata populations. Key words Anastrepha striata; attraction; GC-EAD; GC-MS; guava and sweet orange volatiles; multilure traps Introduction The ability to locate and recognize host plants is essential for the survival of herbivorous insects and their progeny. During host location, insects use a number of sensory stimuli, including visual, olfactory, gustatory and tactile cues as well as humidity and light intensity (Bernays & Correspondence: Edi A. Malo, Grupo de Ecolog´ ıa de Artr´ opodos y Manejo de plagas, El Colegio de la Frontera Sur (ECOSUR), Carretera Antiguo Aeropuerto km 2.5, Tapachula, Chiapas CP 30700, M´ exico. Tel: Mex (52) 9626289800; Fax: Mex (52) 9626289806; email: emr@ecosur.mx Chapman, 1994; Pickett & Glinwood, 2008). Herbivorous insects can use volatile compounds to locate host plants for feeding and/or oviposition or mating sites (Bernays & Chapman, 1994; Renwick & Chew, 1994). Insects are able to identify and discriminate odor sources by processing several volatiles in the bouquet (Clifford & Riffell, 2013). Insects may detect a host plant via olfactory cues by using either species-specific compounds or specific ratios of ubiquitous compounds (Bruce et al., 2005). Several stud- ies have shown that polyphagous tephritids are attracted to fruit volatiles. For instance, the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is attracted to coffee volatiles (Warthen et al., 1997; Prokopy et al., 1998). The Mexican fruit fly, Anastrepha ludens (Loew), is attracted C  2015 Institute of Zoology, Chinese Academy of Sciences 720