Skip to main content
bioRxiv
  • Home
  • About
  • Submit
  • ALERTS / RSS
Advanced Search
New Results

The scent of the fly

Paul G. Becher, Sebastien Lebreton, Erika A. Wallin, Erik Hedenström, Felipe Borrero, Marie Bengtsson, Volker Jörger, View ORCID ProfilePeter Witzgall
doi: https://doi.org/10.1101/206375
Paul G. Becher
1Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053 Alnarp, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Sebastien Lebreton
1Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053 Alnarp, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Erika A. Wallin
2Department of Chemical Engineering, Mid Sweden University, Holmgatan 10, 85170 Sundsvall, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Erik Hedenström
2Department of Chemical Engineering, Mid Sweden University, Holmgatan 10, 85170 Sundsvall, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Felipe Borrero
3Biological Control Laboratory, Colombian Corporation of Agricultural Research, AA 240142 Las Palmas, Bogota, Colombia
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Marie Bengtsson
1Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053 Alnarp, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Volker Jörger
4Staatliches Weinbauinstitut, Merzhauserstr. 119, 79100 Freiburg, Germany
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Peter Witzgall
1Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102, 23053 Alnarp, Sweden
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Peter Witzgall
  • For correspondence: peter.witzgall@slu.se
  • Abstract
  • Full Text
  • Info/History
  • Metrics
  • Preview PDF
Loading

Abstract

(Z)-4-undecenal (Z4-11Al) is the volatile pheromone produced by females of the vinegar fly Drosophila melanogaster. Female flies emit Z4-11Al at few nanograms per hour, for species-specific communication and mate-finding. Tests with synthetic Z4-11Al show that it has a characteristic off-flavour, which we perceive even at the small amounts produced by one 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. A wine-tasting panel finds that we sense as little as 1 ng synthetic Z4-11Al in a glass of wine, and 10 ng Z4-11Al 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.

1. Introduction

All living things communicate with chemicals. Unlike sounds or sights, chemicals interconnect species across the kingdoms, and enable information exchange between animals, plants and microorganisms [1]. A fascinating, recurrent observation is that the same compound is bioactive in different species and context. The evolutionary convergence of semiochemicals may be due to their physico-chemical properties but is first of all expected to reflect biological significance, including the underlying biochemical pathways and precursors.

Linalool, for example, is found in foliage, flowers and fruit of many plants. Herbivory upregulates linalool production, which protects against further infestation [2]. Plant-produced linalool enhances mate-finding in some plant-feeding insects, while other species release linalool as a sex pheromone component [3–⇓⇓6]. The (R) and (S) enantiomers differentially attract pollinators and herbivores, for feeding and oviposition [7–⇓9], and enantiomeric changes during phenological development modulate our perception of flower aroma [10]. In mammals, linalool induces psychopharmalogical effects via glutamate receptors [11,12], perception via odorant receptors (Ors) produces a sweet, floral note and makes a prominent contribution to the bouquet of flowers, fruit and wine, where both grape and yeast are a source of linalool [13–⇓15].

Citrus fruit is a preferred oviposition substrate for the fruit fly Drosophila melanogaster [16], provided that yeast is present [17]. Both citrus peel and brewer’s yeast produce linalool [14,18], which the flies perceive via several Ors, including Or69a [19,20]. Interestingly, the Or69a olfactory channel encodes in addition the recently identified fly pheromone (Z)-4-undecenal (Z4-11Al) [20], which is also found in citrus peel [18].

While collecting volatiles from D. melanogaster flies, we discovered that we can reliably distinguish single male from female flies by their scent, which is strongly reminiscent of Z4-11Al. We therefore employed a sensory panel to verify whether we can indeed discern single flies, and whether the newly discovered pheromone Z4-11Al contributes to the scent of the female fly.

2. Materials and methods

(a) Chemicals

Isomeric and chemical purity of synthetic Z4-11Al were 98.6% and >99.9%, respectively, according to gas chromatography coupled to mass spectrometry (6890 GC and 5975 MS, Agilent Technologies, Santa Clara, CA, USA). Ethanol (redistilled, >99.9% purity; Merck, Darmstadt, Germany) was used as solvent.

(b) Sensory evaluation

Eight me members of the sensory panel for organoleptic tests for the wine-growing area of Baden (Germany) evaluated the odour of D. melanogaster and synthetic Z4-11Al. Each test comprised three glasses, control and two treatments, which were presented in random order. The panel was asked to score odour intensity, ranging from 1 (weak, silent) to 9 (strong, loud) and to comment on odour quality. The first test compared the odour from single male and female flies. Flies were kept during 5 min in empty wine tasting glasses (215 ml) and were released shortly before tests. The second test compared a glass impregnated with fly odour and Z4-11Al (10 ng in 10 μl ethanol), which was applied to an empty glass, the solvent was allowed to evaporate during 2 min. Next, 10 ng Z4-11Al or a female fly were added to a glass filled with either water or white wine (dry Pinot blanc, Freiburg 2013, Staatsweinkellerei Freiburg). The fly was removed after 5 min, prior to testing. Finally, 1 or 5 ng Z4-11Al was added to wine.

(c) Statistical analysis

Odor panel data was analyzed using one-tailed analysis of variance (ANOVA) followed by a Tukey test. Normality was tested using Shapiro-Wilk and homoscedasticity was tested using Levene’s test. All analysis were carried out using SPSS v. 20 (IBM Corp, 2011).

3. Results

D. melanogaster females (figure 1) produce a distinctive scent. The sensory panel found the odour of single female flies to be stronger and qualitatively clearly different from male flies (figure 2a).

Fig. 1
  • Download figure
  • Open in new tab
Fig. 1

Fruit fly D. melanogaster female with exposed ovipositor on blueberry (Picture by Cyrus Mahmoudi).

(colour & high resolution version available).

Fig. 2
  • Download figure
  • Open in new tab
Fig. 2

Sensory evaluation of fly odor and synthetic (Z)-4-undecenal (Z4-11Al). Odor intensity scale ranges from 1 (weak) to 9 (strong), symbols show evaluation by individual test panel members, mean intensity ratings followed by different letters are significantly different (p<0.001). Olfactory intensity of (a) the odour of a single D. melanogaster male and female fly adsorbed during 5 min in an empty wine glass (F=96.711), (b) 10 ng synthetic Z4-11Al and solvent (ethanol) (F=106.732), (c) 10 ng Z4-11Al and the odour of a single D. melanogaster female fly in an empty glass (F=34.720), (d) in a glass with water (F=16.689), (e) in a glass with wine (F=12.952), (f) 1 ng and 5 ng Z4-11Al in a glass with wine (F=110.694).

Chemical analysis has shown earlier that Z4-11Al and its precursor, the cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene, are produced by female flies, not by males [20,21]. Our panel tests established that synthetic Z4-11Al has a distinctive odour (figure 2b). Moreover, a female fly and 10 ng Z4-11Al were found to be similar, with respect to odour quality and intensity, when presented in an empty glass, in water or wine (figure 2c,d,e). Since 10 ng Z4-11Al was assessed as slightly louder than the odour of a fly, we compared Z4-11Al at 1 ng and 5 ng, showing that as little as 1 ng Z4-11Al was clearly perceptible (Fig. 2f). Even at small amounts, Z4-11Al was perceived as a somewhat unpleasant off-flavour.

The detection threshold for Z4-11Al is apparently similar in flies and men, since we clearly sense Z4-11Al released from a single fly (figure 2a). Chemical analysis found that D. melanogaster females released Z4-11Al at a rate of 2.4 ng/h and solvent extracts of fly cuticula contained 0.3 ng Z4-11Al/female [20].

4. Discussion

The sensory panel confirmed that we sensitively smell Z4-11Al, the female-produced pheromone of the fruit fly D. melanogaster [20] and that we can reliably distinguish single female from male flies. This supports the observation that one fly spoils a glass of wine, after falling into it - provided it is of the female sex. Other fly volatiles may contribute to our perception of fly odour. However, Z4-11Al is the most abundant compound released by females only, whereas other, structurally related compounds are found in both sexes [20].

An explanation for convergent perception of Z4-11Al is, however, not at hand. Little is known about the occurrence of Z4-11Al in nature and a possible biological role in humans remains unclear. Z4-11Al has also been found in citrus peel [18] and in the anal gland of the rabbit, where perception effects heart rate [22].

A characteristic citrus-like scent emanates from colonies of crested auklet, a seabird (Douglas et al. 2001). Two unsaturated aldehydes, including (Z)-4-decenal (Z4-10Al) are main constitutents of this bird odour [23]. In crested auklet, Z4-10Al likely plays a role as an ectoparasite repellent and a signal of mate quality [23,24]. (E)-2-nonenal is another odour-active unsaturated aldehyde, found in mushrooms and wine [25–⇓27].

The olfactory sense in animals plays a key role during habitat adaptation. Tuning of Ors to habitat cues is thought to create a bias for mate-finding signals that match or are structurally similar to habitat odorants [28]. This idea yields a tentative scenario for the convergence of semiochemicals. Insects and other animals have long been associated with yeasts that facilitate digestion of plant materials, provide nutrients and protection of food from antagonistic microorganisms.

Yeast and fruit volatiles could have mediated aggregations at feeding sites, while fly-produced compounds sharing structural motifs, may have been secondarily been adopted as mating signals via established sensory channels dedicated to habitat odorants. The phylogenetic divergence of Drosophila Ors is accessible to experimental investigation. A current challenge is to extend studies of Or phylogenetic divergence from insects to mammals, towards an understanding of the chemical vocabulary that interconnects us with other living things.

Data accessibility

Data is completely included in the figure.

Authors’ contributions

P.G.B. sensed the fly scent, P.G.B., S.L., M.B. and V.J. conceived the idea and contributed to the experiment, F.B. calculated statistics, E.W. and E.H. synthesized the test chemical, P.W. supervised the project and wrote the manuscript, all authors contributed to and approved the final version of the manuscript.

Competing interest

Authors declare no competing interests.

Funding

Supported by the Linnaeus initiative "Insect Chemical Ecology, Ethology and Evolution" (Formas, SLU).

Acknowledgements

We thank the members of the sensory panel (Freiburg, Germany) for evaluating the fly scent and Cyrus Mahmoudi (comgraphix.de, Germany) for sharing a fruit fly photograph.

References

  1. 1.↵
    Schultz JC, Appel HM. 2004 Cross-kingdom cross-talk: hormones shared by plants and their insect herbivores. Ecology 85, 70–77. (doi: 10.1890/02-0704).
    OpenUrlCrossRefWeb of Science
  2. 2.↵
    Mithöfer A, Boland W. 2012 Plant defense against herbivores:chemical aspects. Annu. Rev. Plant Biol. 63, 431–450. (doi: 10.1146/annurev-arplant-042110-103854)
    OpenUrlCrossRefPubMedWeb of Science
  3. 3.↵
    Hefetz A, Batra SWT, Blum MS. 1979 Linalool, neral and geranial in the mandibular glands of Colletes bees - an aggregation pheromone. Cell. Molec. Life Sc. 35, 319–320. (doi:10.1007/BF01964324)
    OpenUrlCrossRef
  4. 4.↵
    Aldrich JR, Lusby WR, Kochansky JP. 1986 Identification of a new predaceous stink bug pheromone and its attractiveness to the eastern yellowjacket. Cell Molec Life Sc. 42, 583–585. (doi:10.1007/BF01946714)
    OpenUrlCrossRef
  5. 5.↵
    Leal WS, Sawada M, Matsuyama S, Kuwahara Y, Hasegawa M. 1993 Unusual periodicity of sex pheromone production in the large black chafer Holotrichia parallela. J. Chem. Ecol. 19, 1381–1391. (doi:10.1007/BF00984883)
    OpenUrlCrossRefPubMedWeb of Science
  6. 6.↵
    Yang Z, Bengtsson M, Witzgall P. 2004 Host plant volatiles synergize response to sex pheromone in codling moth, Cydia pomonella. J. Chem. Ecol. 30, 619–629. (doi:10.1023/B:J0EC.0000018633.94002.af)
    OpenUrlCrossRef
  7. 7.↵
    Reisenman CE, Riffell JA, Bernays EA, Hildebrand JG. 2010 Antagonistic effects of floral scent in an insect-plant interaction. Proc. R. Soc. B. 277, 2371–2379. (doi:10.1098/rspb.2010.0163)
    OpenUrlCrossRefPubMedWeb of Science
  8. 8.↵
    Saveer AM, Kromann S, Birgerson G, Bengtsson M, Lindblom T, Balkenius A, Hansson BS, Witzgall P, Becher PG, Ignell R. 2012 Floral to green:mating switches moth olfactory coding and preference. Proc. R. Soc. B 279, 2314–2322. (doi:10.1098/rspb.2011.2710)
    OpenUrlCrossRefPubMed
  9. 9.↵
    Raguso RA. 2016 More lessons from linalool: insights gained from a ubiquitous floral volatile. Curr. Op. Plant Biol. 32, 31–36. (doi:10.1016/j.pbi.2016.05.007)
    OpenUrlCrossRef
  10. 10.↵
    Pragadheesh VS, Chanotiya CS, Rastogi S, Shasany AK (2017) Scent from Jasminum grandiflorum flowers: investigation of the change in linalool enantiomers at various developmental stages using chemical and molecular methods. Phytochemistry 140, 83–94. (doi:10.1016/j.phytochem.2017.04.018).
    OpenUrlCrossRef
  11. 11.↵
    Elisabetsky E, Marschner J, Souza DO. 1995 Effects of linalool on glutamatergic system in the rat cerebral cortex. Neurochem. Res. 20, 461–465. (doi:10.1007/BF00973103)
    OpenUrlCrossRefPubMed
  12. 12.↵
    Nakamura A, Fujiwara S, Matsumoto I, Abe K. 2009 Stress repression in restrained rats by (R)-(-)-linalool inhalation and gene expression profiling of their whole blood cells. J. Agric. Food Chem. 57, 5480–5485. (doi:10.1021/jf900420g)
    OpenUrlCrossRefPubMedWeb of Science
  13. 13.↵
    Lewinsohn E, Schalechet F, Wilkinson J, Matsui K, Tadmor Y, Nam KH, Amar O, Lastochkin E, Larkov O, Ravid U, Hiatt W, Gepstein S, Pichersky E. 2001 Enhanced levels of the aroma and flavor compound S-linalool by metabolic engineering of the terpenoid pathway in tomato fruits. Plant Physiol. 127, 1256–1265. (doi:10.1104/pp.010293)
    OpenUrlAbstract/FREE Full Text
  14. 14.↵
    Carrau FM, Medina K, Boido E, Farina L, Gaggero C, Dellacassa E, Versini G, Henschke PA. 2005 De novo synthesis of monoterpenes by Saccharomyces cerevisiae wine yeasts. FEMS Microbiol. Lett. 243, 107–15. (doi:10.1016/j.femsle.2004.11.050)
    OpenUrlCrossRefPubMed
  15. 15.↵
    Swiegers JH, Bartowsky EJ, Henschke PA, Pretorius IS. 2005 Yeast and bacterial modulation of wine aroma and flavour. Austral. J. Grape Wine Res. 11, 139–173. (doi:10.1111/j.1755-0238.2005.tb00285.x)
    OpenUrlCrossRefWeb of Science
  16. 16.↵
    Dweck HK, Ebrahim SA, Kromann S, Bown D, Hillbur Y, Sachse S, Hansson BH, Stensmyr MC. 2013 Olfactory preference for egg laying on citrus substrates in Drosophila. Curr. Biol. 23, 2472–80. (doi:10.1016/j.cub.2013.10.047)
    OpenUrlCrossRefPubMed
  17. 17.↵
    Becher PG, Flick G, Rozpedowska E, Schmidt A, Hagman A, Lebreton S, Larsson MC, Hansson BS, Piskur J, Witzgall P, Bengtsson M. 2012 Yeast, not fruit volatiles mediate attraction and development of the fruit fly Drosophila melanogaster. Funct. Ecol. 26, 822–828 (doi: 10.1111/j.1365-2435.2012.02006.x)
    OpenUrlCrossRefWeb of Science
  18. 18.↵
    Chisholm MG, Jell JA, Cass DM. 2003 Characterization of the major odorants found in the peel oil of Citrus reticulata Blanco cv. Clementine using gas chromatography-olfactometry. Flavour Fragrance J. 18, 275–281. (doi:10.1002/ffj.1172.)
    OpenUrlCrossRef
  19. 19.↵
    Münch D, Galizia CG. 2016 DoOR 2.0 - comprehensive mapping of Drosophila melanogaster odorant responses. Sci Rep. 6, 21841. (doi:10.1038/srep21841)
    OpenUrlCrossRefPubMed
  20. 20.↵
    Lebreton S, Borrero-Echeverry F, Gonzalez F, Solum M, Wallin E, Hedenstrom E, Hansson BS, Gustavsson A-L, Bengtsson M, Birgersson G, Walker WB, Dweck H, Becher PG, Witzgall P. 2017 A Drosophila female pheromone elicits species-specific long-range attraction via an olfactory channel with dual specificity for sex and food. BMC Biology 15, 88. (doi:10.1186/s12915-017-0427-x)
    OpenUrlCrossRef
  21. 21.↵
    Billeter JC, Atallah J, Krupp JJ, Millar JG, Levine JD. 2009 Specialized cells tag sexual and species identity in Drosophila melanogaster.Nature 461, 987–U250. (doi:10.1038/nature08495)
    OpenUrlCrossRefPubMedWeb of Science
  22. 22.↵
    Goodrich BS, Hesterman ER, Murray KE, Mykytowycz R, Stanley G, Sugowdz G. 1978 Identification of behaviorally significant volatile compounds in the anal gland of the rabbit, Oryctolagus cuniculus. J. Chem. Ecol. 4, 581–594. (doi:10.1007/BF00988922)
    OpenUrlCrossRef
  23. 23.↵
    Douglas H, Jones T, Conner W. 2001 Heteropteran chemical repellents identified in the citrus odor of a seabird (crested auklet: Aethia cristatella): evolutionary convergence in chemical ecology. Naturwissensch. 88, 330–332. (doi:10.1007/s001140100236)
    OpenUrlCrossRefPubMedWeb of Science
  24. 24.↵
    Caro SP, Balthazart J. 2010 Pheromones in birds: myth or reality? J. Comp. Physiol. A 196, 751–766. (doi:10.1007/s00359-010-0534-4)
    OpenUrlCrossRefPubMedWeb of Science
  25. 25.↵
    Wood WF, Brandes ML, Watson RL, Jones RL, Largent DL. 1994 trans-2-Nonenal, the cucumber odor of mushrooms. Mycologia 4, 561–563. (doi: 10.2307/3760750)
    OpenUrlCrossRef
  26. 26.↵
    Chatonnet P, Dubourdieu D. 1998 Identification of substances responsible for the ‘sawdust’ aroma in oak wood. J. Sc. Food Agric. 76, 179–188. (doi:10.1002/(SICI)1097-0010(199802)76:2<179::AID-JSFA924>3.3.CO;2-Y)
    OpenUrlCrossRef
  27. 27.↵
    Ferreira V, Culleré L, López R, Cacho J. 2004 Determination of important odor-active aldehydes of wine through gas chromatography-mass spectrometry of their O-(2, 3, 4, 5, 6-pentafluorobenzyl) oximes formed directly in the solid phase extraction cartridge used for selective isolation. J. Chromatogr. A 1028, 339–345. (doi:10.1016/j.chroma.2003.11.104)
    OpenUrlCrossRef
  28. 28.↵
    Endler JA. 1992 Signals, signal conditions, and the direction of evolution. Am. Naturalist 139, s125–S153. (doi:10.1086/285308)
    OpenUrlCrossRefWeb of Science
Back to top
PreviousNext
Posted October 20, 2017.
Download PDF
Email

Thank you for your interest in spreading the word about bioRxiv.

NOTE: Your email address is requested solely to identify you as the sender of this article.

Enter multiple addresses on separate lines or separate them with commas.
The scent of the fly
(Your Name) has forwarded a page to you from bioRxiv
(Your Name) thought you would like to see this page from the bioRxiv website.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
The scent of the fly
Paul G. Becher, Sebastien Lebreton, Erika A. Wallin, Erik Hedenström, Felipe Borrero, Marie Bengtsson, Volker Jörger, Peter Witzgall
bioRxiv 206375; doi: https://doi.org/10.1101/206375
Reddit logo Twitter logo Facebook logo LinkedIn logo Mendeley logo
Citation Tools
The scent of the fly
Paul G. Becher, Sebastien Lebreton, Erika A. Wallin, Erik Hedenström, Felipe Borrero, Marie Bengtsson, Volker Jörger, Peter Witzgall
bioRxiv 206375; doi: https://doi.org/10.1101/206375

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Subject Area

  • Animal Behavior and Cognition
Subject Areas
All Articles
  • Animal Behavior and Cognition (4229)
  • Biochemistry (9118)
  • Bioengineering (6753)
  • Bioinformatics (23949)
  • Biophysics (12103)
  • Cancer Biology (9498)
  • Cell Biology (13746)
  • Clinical Trials (138)
  • Developmental Biology (7618)
  • Ecology (11666)
  • Epidemiology (2066)
  • Evolutionary Biology (15479)
  • Genetics (10621)
  • Genomics (14298)
  • Immunology (9468)
  • Microbiology (22808)
  • Molecular Biology (9083)
  • Neuroscience (48900)
  • Paleontology (355)
  • Pathology (1479)
  • Pharmacology and Toxicology (2566)
  • Physiology (3828)
  • Plant Biology (8320)
  • Scientific Communication and Education (1467)
  • Synthetic Biology (2294)
  • Systems Biology (6172)
  • Zoology (1297)