Peripheral modulation of pheromone response by inhibitory host compound in a beetle.
Author
Summary, in English
We identified several compounds, by gas chromatographic–electroantennographic detection (GC–EAD), that were antennally active in the bark beetle Ips typographus and also abundant in beetle-attacked spruce trees. One of them, 1,8-cineole (Ci), strongly inhibited the attraction to pheromone in the field. Single-sensillum recordings (SSRs) previously showed olfactory receptor neurons (ORNs) on I. typographus antennae selectively responding to Ci. All Ci neurons were found within sensilla co-inhabited by a pheromone neuron responding to cis-verbenol (cV); however, in other sensilla, the cV neuron was paired with a neuron not responding to any test odorant. We hypothesized that the colocalization of ORNs had a functional and ecological relevance. We show by SSR that Ci inhibited spontaneous activity of the cV neuron only in sensilla in which the Ci neuron was also present.
Using mixtures of cV and Ci, we further show that responses to low doses (1–10ng) of cV were significantly reduced when the colocalized Ci neuron simultaneously responded to high doses (1–10ug) of Ci. This indicated that the response of the Ci neuron, rather than ligand–receptor interactions in the cV neuron, caused the inhibition. Moreover, cV neurons paired with Ci neurons were more sensitive to cV alone than the ones paired with the non-responding ORN. Our observations question the traditional view that ORNs within a sensillum function as independent units. The colocalization of ORNs might sharpen adaptive responses to blends of semiochemicals with different ecological significance in the olfactory landscape.
Using mixtures of cV and Ci, we further show that responses to low doses (1–10ng) of cV were significantly reduced when the colocalized Ci neuron simultaneously responded to high doses (1–10ug) of Ci. This indicated that the response of the Ci neuron, rather than ligand–receptor interactions in the cV neuron, caused the inhibition. Moreover, cV neurons paired with Ci neurons were more sensitive to cV alone than the ones paired with the non-responding ORN. Our observations question the traditional view that ORNs within a sensillum function as independent units. The colocalization of ORNs might sharpen adaptive responses to blends of semiochemicals with different ecological significance in the olfactory landscape.
Department/s
Publishing year
2010
Language
English
Pages
3332-3339
Publication/Series
Journal of Experimental Biology
Volume
213
Document type
Journal article
Publisher
The Company of Biologists Ltd
Topic
- Zoology
- Biological Sciences
Keywords
- Ips typographus
- Coleoptera
- Curculionidae
- Scolytinae
- single-sensillum recording
- olfactory receptor neuron
- colocalization
- co-compartmentalization
- host selection
- blend discrimination
Status
Published
Research group
- Pheromone Group
ISBN/ISSN/Other
- ISSN: 1477-9145