Functional Characteristics of a Tiny but Specialized Olfactory System: Olfactory Receptor Neurons of Carrot Psyllids (Homoptera: Triozidae)

Abstract

With only approximately 50 olfactory receptor neurons (ORNs), the carrot psyllid Trioza apicalis (Homoptera: Psylloidea) may have the smallest olfactory system described in adult Neopteran insects. Using single sensillum recordings (SSR) and gas chromatograph-linked SSR, we characterized 4 olfactory sensilla forming a distinct morphological type, which together house approximately 25% of all ORNs. We recorded responses to extracts and single constituents from Daucus carota ssp. sativus, from the conifers Picea abies, Pinus sylvestris, and Juniperus communis, as well as from male and female T. apicalis. Receptor neurons were highly selective; only 9 compounds in total elicited repeatable responses, and each neuron responded to at most 3 individual compounds. Chemical profiles of carrot and conifers showed significant overlap, with 4 out of 9 electrophysiologically active compounds occurring in more than one type of extract, but a carrot-specific compound elicited the most repeated responses. We identified 4 tentative neuron classes and found a rather high degree of neuronal redundancy, with 1 neuron class present in 3 and another present in all 4 of the sensilla, respectively.

Functional evolution of Lepidoptera olfactory receptors revealed by deorphanization of a moth repertoire

“…In moths, such specific pathways have been very well described for sex pheromone perception, but it remains unclear whether they also exist for salient plant odorants. Electrophysiological studies performed on S. littoralis and a range of herbivorous insects demonstrate that they are all equipped with numerous sensory neurons narrowly tuned to common plant volatiles162123535455. Although some specialist species detect compounds specific to a narrow range of plant taxa, a majority of herbivorous insects discriminate host from non-host plants through specific combinations of more ubiquitous odorants.…”

Characterization of olfactory sensory neurons in the white clover seed weevil, Apion fulvipes (Coleoptera: Apionidae)

“…SSR using electrolytically sharpened tungsten microelectrodes were performed using standard equipment (from Syntech, Kirchzarten, Germany) and well-established experimental protocols (Andersson et al, 2009b;Kristoffersen et al, 2008;Stensmyr et al, 2003). A live insect was mounted in dental wax on a microscope slide and the antennae were fixed, in the wax, in a position that allowed for insertion of the recording electrode.…”

Multimodal Cues Drive Host-Plant Assessment in Asian Citrus Psyllid (Diaphorina citri)

“…A number of psyllid species (Moran and Brown 1973;Lapis and Borden 1993;Soroker et al 2004;Finley-Doney and Walter 2005;Kristoffersen et al 2008;Mayer et al 2008aMayer et al ,b, 2011 are responsive to olfactory cues emitted by their host-plants. Given the aromaticity of rutaceous plants, it is reasonable to expect that olfactory stimuli play an important role in D. citri host-plant Þnding behaviors, and indeed initial studies indicate this to be the case (Wenninger et al 2009, Patt andSé tamou 2010).…”