Antennal olfactory responses of adult meadow spittlebug, Philaenus spumarius, to volatile organic compounds (VOCs)

Abstract

The meadow spittlebug, Philaenus spumarius L. (Hemiptera, Aphrophoridae) is a commonly found vector of Xylella fastidiosa Wells et al. (1987) strain subspecies pauca associated with the “Olive Quick Decline Syndrome” in Italy. To contribute to the knowledge of the adult P. spumarius chemoreceptivity, electroantennographic (EAG) responses of both sexes to 50 volatile organic compounds (VOCs) including aliphatic aldehydes, alcohols, esters, and ketones, terpenoids, and aromatics were recorded. Measurable EAG responses were elicited by all compounds tested. In both sexes, octanal, 2-octanol, 2-decanone, (E)-2-hexenyl acetate, and vanillin elicited the strongest antennal amplitude within the chemical groups of aliphatic saturated aldehydes, aliphatic alcohols, aliphatic acetates and aromatics, respectively. Male and female EAG responses to sulcatol, (±)linalool, and sulcatone were higher than those to other terpenoinds. In both sexes, the weakest antennal stimulants were phenethyl alcohol and 2-pentanone. Sexual differences in the EAG amplitude were found only for four of test compounds suggesting a general similarity between males and females in antennal sensitivity. The olfactory system of both sexes proved to be sensitive to changes in stimulus concentration, carbon chain length, and compound structure. Compounds with short carbon chain length (C5—C6) elicited lower EAG amplitudes than compounds with higher carbon chain length (C9—C10) in all classes of aliphatic hydrocarbons with different functional groups. The elucidation of the sensitivity profile of P. spumarius to a variety of VOCs provides a basis for future identification of behaviorally-active compounds useful for developing semiochemical-based control strategies of this pest.

Electrophysiological and behavioural response of Philaenus spumarius to essential oils and aromatic plants

“…Moreover, differences in the male and female perception of some concentrations of the three EOs demonstrated the capability of the insects' olfactory system to perceive them selectively. All these observations further confirm the antennal responsiveness of adult P. spumarius to a wide range of VOCs 33 . Moreover, in this study, spittlebug adults collected from different herbaceous plants in two different areas gave similar EAG responses to different concentrations of the three EOs thus suggesting a common innate responsiveness to the stimuli tested.…”

“…The EAG responses of P. spumarius male and female antennae to increasing concentrations (0.01-100 µg/µL) of the three EOs were measured by the EAG technique similar to that used in previous studies 33,53 . In order to prevent the rapid evaporation of test compounds, EOs were dissolved in mineral oil (Sigma-Aldrich, Milan, Italy) and stored at −20 °C until needed.…”

“…Previous studies, demonstrated the presence of basiconic and coeloconic sensilla with a putative olfactory function on the male and female antennae of P. spumarius adults 32 and electroantennographic tests demonstrated the capability of adult meadow spittlebug to perceive a wide range of volatile organic compounds (VOCs) including aliphatic aldehydes, alcohols, esters, ketones, terpenoids, and aromatic compounds 33 . In order to enhance the availability of practical tools for the management of the spittlebug populations, in the present study the sensitivity of male and female antennae to EOs of Pelargonium graveolens (Geraniaceae), Cymbopogon nardus (Poaceae) and Lavandula officinalis (Labiatae) was investigated by electroantennography and the behavioural responses of adult insects to EOs and related plants was determined using Y-tube olfactometer bioassays.…”

Association between olfactory sensitivity and behavioral responses of Drosophila suzukii to naturally occurring volatile compounds

“…The dose‐response relationships we found indicate that female flies present an olfactory sensitivity to eugenol, menthol, and vanillin, but not to cis ‐jasmone. Vanillin has been found to elicit EAG responses also in the meadow spittlebug P. spumarius (Germinara et al, 2017). In addition, our results indicate that the OSNs respond in a dose‐dependent manner when stimulated with a binary mixture of the naturally occurring odorants.…”

“…These compounds are naturally occurring and showed biological activity in different studies aimed at developing control strategies of different pests. In fact, eugenol exhibited repellent action on larvae and adult ticks (Del Fabbro & Nazzi, 2013; Zeringota et al, 2013), and genotoxic effect on D. melanogaster (Munerato et al, 2005); vanillin increased the repellence times of DEET against mosquitoes (Kamsuk et al, 2007) and evoked the strongest antennal responses in adults of Philaenus spumarius (Germinara et al, 2017); menthol displayed moderate repellent action on D. suzukii populations in Canada (Renkema et al, 2016) and Republic of Korea (Park et al, 2016); finally, plants treated with cis ‐jasmone were more repellent to aphid Macrosiphum euphorbiae (Sobhy et al, 2017).…”