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

GONZALEZ AUDINO P.; KASHIWAGI GUSTAVO; MANRIQUE GABRIEL

Valparaiso

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

Universidad Pontificia Valparaiso

Metasternal glands (MG) of Triatoma infestans are a pair ofexocrine 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 thatattract and aggregate males around them (Manrique & Lazzari, 1995).Subsequent works occluding female MGs orifices exhibited a significant decreaseof copulation frequency and males aggregation behavior (Crespo & Manrique,2007), confirming some kind role in sexual communication. Moreover, GC-MSanalyses of volatiles emitted by excised MGs revealed the presence of highlyvolatile aliphatic ketones, alcohols and a tentatively characterized componentaccording to previous findings as 1,3-dioxolane (Manrique et al., 2006; Unelius et al.,2010). These components present a potential as sexual attractants applicable tothe development of vector control techniques in Chagas Disease (e.g., matingdisruption). But until now, GM volatiles could not be detected in the headspaceof mating pairs by GC-MS in full scan mode, being detected only occasionally 3-pentanoneby selective ion monitoring (SIM) mode. Here, we returned to thisissue and sampled the headspace of a mating pair with a three-phase fiber, andanalyzed in full scan mode. Moreover, as it is still unknown which componenttriggers an electrophysiological response, we carried out GC-EAD and EAG studiesusing commercial synthetic compounds: 3-pentanone, 3-pentanol, 2-butanoneand 2-methyl-1-butanol (purity> 99%).Volatiles of the headspace ofvirgin mating pairs collected by DVB/CAR/PDMS fiber were detected in full scanmode by GC-MS and in preliminary experiments almost the same componentspreviously described in the secretion of excised MGs were found in theheadspace of a mating pair. However, as relative composition between firstcollections apparently differed from gland composition, more replicates of HSSPME analysis are needed. In GC-EAD different antennal segments ormultiple antenna were stimulated with MGs synthetic compounds, but no signalcould be detected. Instead, EAG results showed a dose-dependent response withall compounds assayed at high range concentrations.