Electrophysiological studies of metasternal glands (MG) volátiles in Triatoma infestans (Hemiptera: Reduviidae). Reinvestigation of MG emission during mating

GABRIEL MANRIQUE; PAOLA GONZÁLEZ AUDINO; GUSTAVO A. KASHIWAGI

Valparaíso

Congreso; 5th Congress of the Latin American Association of Chemical Ecology; 2018

ALAEQ

Metasternal glands (MG) of Triatoma infestans are a pair of exocrine glands ventrally located at the anterior margin of metacoxal cavity. Early works in the study of sexual behavior in T. infestans, showed that mating couples release volatiles that attract and aggregate males around them (Manrique & Lazzari, 1995). Subsequent works occluding female MGs orifices exhibited a significant decrease of copulation frequency and males aggregation behavior (Crespo & Manrique, 2007), confirming some kind role in sexual communication. Moreover, GC-MS analyses of volatiles emitted by excised MGs revealed the presence of highly volatile aliphatic ketones, alcohols and a tentatively characterized component according to previous findings as 1,3-dioxolane (Manrique et al., 2006; Unelius et al., 2010). These components present a potential as sexual attractants applicable to the development of vector control techniques in Chagas Disease (e.g., mating disruption). But until now, GM volatiles could not be detected in the headspace of mating pairs by GC-MS in full scan mode, being detected only occasionally 3-pentanone by selective ion monitoring (SIM) mode. Here, we returned to this issue and sampled the headspace of a mating pair with a three-phase fiber, and analyzed in full scan mode. Moreover, as it is still unknown which component triggers an electrophysiological response, we carried out GC-EAD and EAG studies using commercial synthetic compounds: 3-pentanone, 3-pentanol, 2-butanone and 2-methyl-1-butanol (purity> 99%).Volatiles of the headspace of virgin mating pairs collected by DVB/CAR/PDMS fiber were detected in full scan mode by GC-MS and in preliminary experiments almost the same components previously described in the secretion of excised MGs were found in the headspace of a mating pair. However, as relative composition between first collections apparently differed from gland composition, more replicates of HS SPME analysis are needed. In GC-EAD different antennal segments or multiple antenna were stimulated with MGs synthetic compounds, but no signal could be detected. Instead, EAG results showed a dose-dependent response with all compounds assayed at high range concentrations.