Chemical Signaling Between Guava (Psidium guajava L., Myrtaceae) and the Guava Weevil (Conotrachelus psidii Marshall)

Abstract

<div class="WordSection1"><p class="Default"> Volatile organic compounds (VOCs) from guava (<em>Psidium guajava </em>L.) reproductive tissues (flower bud, open flower, petal fall, fruit setting, and fruit growth) were collected <em>in situ </em>during the day by headspace-solid phase microextraction (HS-SPME), and from flower bud and fruit setting by dynamic headspace (DHS). The samples were analyzed by GC-MS to separate and identify VOCs produced by guava, which potentially could attract the guava weevil <em>(Conotrachelus psidii </em>Marshall, Coleoptera: Curculionidae), one of the most important pests of guava plants in Colombia and Brazil. The terpenes <em>β</em>-caryophyllene, limonene, and copaene (tentatively identified) were present in all of the guava reproductive tissues, being the major constituents in flower bud and fruit setting, the two guava stages where <em>C. psidii </em>is commonly found. Additionally, the volatile compounds released by male and female insects were separately collected by HS-SPME, and comparatively analyzed by GC-MS. As result, some of volatile detected in the guava reproductive tissues were also released from insects. The behavioral response of the volatile blends and the above-mentioned compounds was studied in a Y-tube olfactometer bioassay, allowing confirming the presence of host kairomones in the guava reproductive tissues.</p></div>

(1R,2S,6R)-Papayanal: a new male-specific volatile compound released by the guava weevilConotrachelus psidii(Coleoptera: Curculionidae)

“…These compounds were present in all of the guava reproductive tissues, being quantitatively relevant in flower buds and fruit setting, the two guava stages where C. psidii is found. 11) Other terpenes, such as α-copaene, α-humulene and aromadendrene, were detected only by DHS and mainly on male insects (except for α-humulene).…”

“…Once transferred to the laboratory, individuals were segregated by sex according to the procedure reported by Silva-Filho et al, 13) and maintained separately in plastic boxes at 20 ± 2°C, at a relative humidity of 80 ± 10% with pieces of green guava fruits as food and 12-h light regime. 11) Insect volatile collection.…”

“…7,8) In addition, previous studies have shown that host plant volatiles are attractive to both sexes of C. psidii. 9,10) Recently Romero-Frías et al 11) identified the terpenes, β-caryophyllene, and limonene in both insects (C. psidii males and females) and plants (flower bud and fruit setting guava stages). Therefore, these results suggested a possible role of these volatiles as host kairomones for C. psidii in the guava reproductive tissues.…”

Profile of Terpenoid Compounds Mediating a Plant‐Herbivore Interaction: Screening by Static Headspace Solid‐Phase Microextraction‐Gas Chromatography/Q‐ToF Mass Spectrometry

“…As in our case, copaene, caryophyllene, and aromadendrene were observed in tissues of fruit setting of Colombian pink guava, whereas terpineol and the farnesene isomers were not observed by the authors. [14] In our study, the emission of caryophyllene by fruit setting was low (2 %) in comparison to that of other volatiles such as hexanal, nonanal, limonene, and cis-3-hexenyl acetate. [18] But in the case of Colombian guava, the emission of limonene was low (5 %) with respect to other compounds.…”

“…Authors reported β-caryophyllene, limonene, and copaene as the main volatile organic compounds involved in the signalization between Conotrachelus psidii Marshall and its host, the Colombian guava. [14] The mentioned compounds are produced during the phenological stages of flower bud and fruit setting. On the other side, papayanol and papayanal were identified as volatile compounds released by C. psidii that play the role of aggregation pheromone.…”