| 1. |
- Becher, Paul, et al.
(författare)
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The Scent of the Fly
- 2018
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Ingår i: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 0098-0331 .- 1573-1561. ; 44:5, s. 431-435
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Tidskriftsartikel (refereegranskat)abstract
- (Z)-4-undecenal (Z4-11Al) is the volatile pheromone produced by females of the vinegar fly Drosophila melanogaster. Female flies emit Z4-11Al for species-specific communication and mate-finding. A sensory panel finds that synthetic Z4-11Al has a characteristic flavour, which can be perceived even at the small amounts produced by a single female fly. Since only females produce Z4-11Al, and not males, we can reliably distinguish between single D. melanogaster males and females, according to their scent. Females release Z4-11Al at 2.4 ng/h and we readily sense 1 ng synthetic Z4-11Al in a glass of wine (0.03 nmol/L), while a tenfold concentration is perceived as a loud off-flavour. This corroborates the observation that a glass of wine is spoilt by a single D. melanogaster fly falling into it, which we here show is caused by Z4-11Al. The biological role of Z4-11Al or structurally related aldehydes in humans and the basis for this semiochemical convergence remains yet unclear.
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| 2. |
- Borrero, Felipe, et al.
(författare)
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The female sex pheromone (Z)-4-undecenal mediates flight attraction and courtship in Drosophila melanogaster
- 2022
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Ingår i: Journal of insect physiology. - : Elsevier BV. - 0022-1910 .- 1879-1611. ; 137
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Tidskriftsartikel (refereegranskat)abstract
- Specific mate communication and recognition underlies reproduction and hence speciation. Our study provides new insights in Drosophila melanogaster premating olfactory communication. Mate communication evolves during adaptation to ecological niches and makes use of social signals and habitat cues. Female-produced, species-specific volatile pheromone (Z)-4-undecenal (Z4-11Al) and male pheromone (Z)-11-octadecenyl acetate (cVA) interact with food odour in a sex-specific manner. Furthermore, Z4-11Al, which mediates upwind flight attraction in both sexes, also elicits courtship in experienced males. Two isoforms of the olfactory receptor Or69a are co-expressed in the same olfactory sensory neurons. Z4-11Al is perceived via Or69aB, while the food odorant (R)-linalool is a main ligand for the other variant, Or69aA. However, only Z4-11Al mediates courtship in experienced males, not (R)-linalool. Behavioural discrimination is reflected by calcium imaging of the antennal lobe, showing distinct glomerular activation patterns by these two compounds. Male sex pheromone cVA is known to affect male and female courtship at close range, but does not elicit upwind flight attraction as a single compound, in contrast to Z4-11Al. A blend of the food odour vinegar and cVA attracted females, while a blend of vinegar and female pheromone Z4-11Al attracted males, instead. Sex-specific upwind flight attraction to blends of food volatiles and male and female pheromone, respectively, adds a new element to Drosophila olfactory premating communication and is an unambiguous paradigm for identifying the behaviourally active components, towards a more complete concept of food-pheromone odour objects.
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| 3. |
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| 4. |
- Frey, T., et al.
(författare)
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The human odorant receptor OR10A6 is tuned to the pheromone of the commensal fruit fly Drosophila melanogaster
- 2022
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Ingår i: iScience. - : Elsevier BV. - 2589-0042. ; 25:11
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Tidskriftsartikel (refereegranskat)abstract
- All living things speak chemistry. The challenge is to reveal the vocabulary, the odorants that enable communication across phylogenies and to translate them to physiological, behavioral, and ecological function. Olfactory receptors (ORs) interface animals with airborne odorants. Expression in heterologous cells makes it possible to interrogate single ORs and to identify cognate ligands. The cosmopolitan, anthropophilic strain of the vinegar fly Drosophila melanogaster depends on human resources and housing for survival. Curiously, humans sense the pheromone (Z)-4-undecenal (Z4-11Al) released by single fly females. A screening of all human ORs shows that the most highly expressed OR10A6 is tuned to Z4-11Al. Females of an ancestral African fly strain release a blend of Z4-11Al and Z4-9Al that produces a different aroma, which is how we distinguish these fly strains by nose. That flies and humans sense Z4-11Al via dedicated ORs shows how convergent evolution shapes communication channels between vertebrate and invertebrate animals.
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| 5. |
- Lebreton, Sebastien, et al.
(författare)
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A Drosophila female pheromone elicits species-specific long-range attraction via an olfactory channel with dual specificity for sex and food
- 2017
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Mate finding and recognition in animals evolves during niche adaptation and involves social signals and habitat cues. Drosophila melanogaster and related species are known to be attracted to fermenting fruit for feeding and egg-laying, which poses the question of whether species-specific fly odours contribute to long-range premating communication. Results: We have discovered an olfactory channel in D. melanogaster with a dual affinity to sex and food odorants. Female flies release a pheromone, (Z)-4-undecenal (Z4-11Al), that elicits flight attraction in both sexes. Its biosynthetic precursor is the cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene (7,11-HD), which is known to afford reproductive isolation between the sibling species D. melanogaster and D. simulans during courtship. Twin olfactory receptors, Or69aB and Or69aA, are tuned to Z4-11Al and food odorants, respectively. They are co-expressed in the same olfactory sensory neurons, and feed into a neural circuit mediating species-specific, long-range communication; however, the close relative D. simulans, which shares food resources with D. melanogaster, does not respond to Z4-11Al. Conclusion: The Or69aA and Or69aB isoforms have adopted dual olfactory traits. The underlying gene yields a collaboration between natural and sexual selection, which has the potential to drive speciation.
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| 6. |
- Lindmark, Matilda
(författare)
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Increased resilience in managed boreal forests : Controlling damage by spruce bark beetle and moose in Sweden
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Most of the forests growing in Europe today have been planted, or heavily affected, by humans. This is because the forest industry provides crucial raw materials for diverse products, including timber, pulp and paper, cellulose-based substances and renewable energy sources. However, forest management has turned heterogenic natural forests into homogenous forest stands that are highly susceptible to various kinds of damage. This thesis focuses on moose (Alces alces L.) browsing and attacks by spruce bark beetle (Ips typographus L.), both of which cause large economic losses. Empirically, it is based on field experiments conducted in managed forests in Sweden. Moose browsing on vulnerable top shoots of young pines during wintertime is a substantial problem in northern Europe. My colleagues and I (hereafter we) found that extracts of spruce trees (which moose prefer less than pine) can act as efficient natural browsing repellents.Spruce bark beetles attack spruce (Picea abies) trees throughout Europe. Thus, we also evaluated the field behavior of the beetles exposed to non-host- and fungal volatiles in efforts to identify more efficient ways to protect susceptible spruce stands. In addition, we evaluated the predator:prey ratio between the beetles and Thanasimus predators in representative forest stands, to assist efforts to enhance the biological control of spruce bark beetles in managed forests. Finally, we investigated changes in bacterial communities in wood after attacks by spruce bark beetles to improve knowledge of their ecology.Changes in forest management regime are needed to increase structural and tree species diversity, and thus raise forests’ resilience and ability to cope with ongoing climate change. Results presented in this thesis indicate that changing forest management to increase the variation in tree species variation will enhance the resilience of managed forests, thereby reducing damaging by both moose and spruce bark beetle.
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| 7. |
- Lindmark, Matilda, et al.
(författare)
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Protecting forest edges using trap logs – Limited effects of associated push-pull strategies targeting Ips typographus
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 505
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Tidskriftsartikel (refereegranskat)abstract
- Bark beetles can cause epidemic outbreaks and kill millions of cubic meters of economical and ecologically important forests around the world. It is well known what attracts and what repels different species of bark beetle, and these chemical cues can be used to protect trees and catch the beetles without using pesticides. Applying this knowledge, we investigated the use of push–pull strategies with trap logs along susceptible edges of a Swedish boreal spruce forest. The repellents (push) used were non-host volatiles (NHV) attached to tree trunks at the forest edge, and the attractants (pull) was a commercial aggregation pheromone attached to trap logs. The aim was to test whether the Ips typographus catch could be significantly increased by combining a push–pull system with traditional trap logs, thereby providing additional protection. The experiment was performed over two years and included the main flight period of I. typographus. The study sites were clear-cuts that had been harvested the preceding winter, and sun-exposed forest edges of mature spruce were targeted for protection. A full factorial setup was used comprising two treatments (repellent and attractant) and a control. Seven replicates of the trap logs were used, three during the first year and four during the second. The number of established I. typographus maternal galleries per square meter of log surface was used as the response variable. The trap logs captured large numbers of I. typographus, at an average density of 353 and 169 maternal galleries per m2 during year 1 and year 2, respectively, over all treatments. Based on the catch data, with a sufficient number of trap logs, the risk of tree mortality at forest edges may be reduced and we recommend its general use. However, we did not see any significant effect of either the repellent or the attractant on the density of maternal galleries. Hence, we cannot recommend the addition of chemical cues to improve the efficiency of trap logs. Although trap logs are efficient in capturing bark beetles and hence may protect forest edges, it does not imply that they can provide protection on a larger scale. In line with other studies, we hence recommend that forest management to target nature-based solutions that strengthen the resilience of forest stands, by using mixed forest stands and resistant plant species, and nurture habitats for natural predators of I. typographus.
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| 8. |
- Lindmark, Matilda, et al.
(författare)
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Semiochemicals produced by fungal bark beetle symbiont Endoconidiophora rufipennis and the discovery of an anti-attractant for Ips typographus
- 2023
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 18:4
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Tidskriftsartikel (refereegranskat)abstract
- Bark beetles vector symbiotic fungal species into their host trees during mass attacks. The symbiotic relationship with blue stain fungi of the Ascomycetes, including genera of Endoconidiophora (syn. = Ceratocystis), promotes successful establishment whereby the microbes help to overcome the host trees' defence and degrade toxic resins. This is the first study to evaluate both the volatile emissions from an insect-associated blue stain fungus over time and the insect response in a field trapping experiment. Volatile emissions from isolates of Endoconidiophora rufipennis (ER) were collected by solid-phase microextraction (SPME) and analysed by gas chromatography-mass spectroscopy (GC-MS) over a period of 30 days. This virulent North American fungus is closely related to E. polonica, a symbiotic fungus known from Eurasian spruce bark beetle Ips typographus.Nine volatiles were emitted by ER in substantial amounts: isoamyl acetate, sulcatone, 2-phenethyl acetate, geranyl acetone, geranyl acetate, citronellyl acetate, (R)- and (S)-sulcatol, and (R)-sulcatol acetate. A late peaking compound was geranyl acetone. In the field trapping experiment, three of the fungal volatiles (geranyl acetone, 2-phenethyl acetate and sulcatone) were tested in combination with a synthetic aggregation pheromone for I. typographus. Traps with geranyl acetone attracted lower numbers of I. typographus compared to traps with 2-phenethyl acetate, sulcatone or the pheromone alone as a control. The results showed that geranyl acetone acts as an anti-attractant and may act naturally on I. typographus as a cue from an associated fungus to signal an overexploited host.
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| 9. |
- Rahmani, Rizan, et al.
(författare)
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Identification and Field Assay of Two Aggregation Pheromone Components Emitted by Males of the Bark Beetle Polygraphus punctifrons (Coleoptera: Curculionidae)
- 2019
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Ingår i: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 0098-0331 .- 1573-1561. ; 45:4, s. 356-365
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Tidskriftsartikel (refereegranskat)abstract
- The bark beetle Polygraphus punctifrons (Coleoptera: Curculionidae) is a species that feeds on Norway spruce (Picea abies) and is found in the Northern parts of Europe and Russia. The release of volatile organic compounds (VOCs) produced by males and females of P. punctifrons when the beetles bore into spruce stem sections in a laboratory environment was studied using solid phase microextraction (SPME). The sampled VOCs emitted by boring beetles were analysed by gas chromatography and mass spectrometry (GCMS). (+)-2-[(1R,2S)-1-Methyl-2-(prop-1-en-2-yl)cyclobutyl]ethanol [(+)-(1R,2S)-grandisol] and (−)-(R)-1-isopropyl-4-methyl-3-cyclohexen-1-ol [(−)-(R)-terpinen-4-ol] were identified to be male specific volatiles. The identity of the compounds was confirmed by comparison with synthetic samples. Field trials with synthetic compounds in Sweden showed that racemic grandisol per se was strongly attractive for both males and females, while (−)-(R)-terpinen-4-ol was not. Further, when adding (−)-(R)-terpinen-4-ol to rac-grandisol, a synergistic effect was observed as the trap catch of P. punctifrons was fourfold. (−)-(R)-Terpinen-4-ol by its own did not attract P. punctifrons but Polygraphus poligraphus, and the latter was also attracted to traps baited with a 10:90 mixture of the two compounds. Thus, we have identified (+)-(1R,2S)-grandisol as a main component and (−)-(R)-terpinen-4-ol as a minor component of the aggregation pheromone of P. punctifrons. This opens future possibilities to monitor and, if necessary, manage populations of P. punctifrons.
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| 10. |
- Schiestl, Florian P., et al.
(författare)
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Generalized olfactory detection of floral volatiles in the highly specialized Greya-Lithophragma nursery pollination system
- 2021
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Ingår i: Arthropod-Plant Interactions. - : Springer Science and Business Media LLC. - 1872-8855 .- 1872-8847. ; 15:2, s. 209-221
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Tidskriftsartikel (refereegranskat)abstract
- Volatiles are of key importance for host-plant recognition in insects. In the pollination system of Lithophragma flowers and Greya moths, moths are highly specialized on Lithophragma, in which they oviposit and thereby pollinate the flowers. Floral volatiles in Lithophragma are highly variable between species and populations, and moths prefer to oviposit into Lithophragma flowers from populations of the local host species. Here we used gas chromatography coupled with electroantennographic detection (GC-EAD) to test whether Greya moths detect specific key volatiles or respond broadly to many volatiles of Lithophragma flowers. We also addressed whether olfactory detection in Greya moths varies across populations, consistent with a co-evolutionary scenario. We analyzed flower volatile samples from three different species and five populations of Lithophragma occurring across a 1400 km range in the Western USA, and their sympatric female Greya politella moths. We showed that Greya politella detect a broad range of Lithophragma volatiles, with a total of 23 compounds being EAD active. We chemically identified 15 of these, including the chiral 6, 10, 14-trimethylpentadecan-2-one (hexahydrofarnesyl acetone), which was not previously detected in Lithophragma. All investigated Lithophragma species produced the (6R, 10R)-enantiomer of this compound. We showed that Greya moths detected not only volatiles of their local Lithophragma plants, but also those from allopatric populations/species that they not encounter in local populations. In conclusion, the generalized detection of volatiles and a lack of co-divergence between volatiles and olfactory detection may be of selective advantage for moths in tracking hosts with rapidly evolving, chemically diverse floral volatiles.
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