Abstract
Though it is known that flower scent not only attracts pollinators but also herbivores, little is known about the importance of flower scent on the distribution of leaf herbivores among individuals within a plant species. In this study we determined the distribution of galls induced by the sawfly Pontania proxima (Serville 1823) (Hymenoptera, Tenthredinidae, Nematinae) on flowering and non-flowering representatives of several clones belonging to Salix fragilis and S. × rubens (Salicaceae). Further, amounts and composition of scent of flowering and non-flowering twigs were compared (dynamic headspace-gas chromatography–mass spectrometry, DHS-GC–MS), and a scent sample collected from flowering twigs of S. fragilis was tested by coupled gas chromatography and electroantennographic detection (GC-EAD) on the antennae of P. proxima females. The results show that the presence of flower catkins on plants led to a higher degree of allocation with galls, but the number of galls differed not between flowering and non-flowering plants. The DHS-GC–MS analyses revealed that the total amount of flower scent emitted per flowering twig is about 90 times higher than the scent emitted by a non-flowering twig. Further, several compounds were emitted only by flowering but not by non-flowering twigs. In the GC-EAD analyses, antennae consistently responded not only to green leaf volatiles, but also to compounds emitted only by the flowers (e.g. 1,4-dimethoxybenzene). These flower scent compounds are suggested to affect the host plant choice by attracting more sawflies from the distance to flowering plants compared to non-flowering plants. The EAD-active compounds emitted from vegetative plant parts are assumed to act as long-distance signals especially when flowers are absent on host plants, e.g. during the oviposition period of the second generation of P. proxima.
References
Adams R (2007) Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry. Allured Publishing Corporation, Illinois
Amirav A, Dagan S (1997) A direct sample introduction device for mass spectrometry studies and gas chromatography mass spectrometry analyses. Eur J Mass Spectrom 3:105–111
Barker AM, Molotsane R, Müller C, Schaffner U, Städler E (2006) Chemosensory and behaviourial responses of the turnip sawfly Athalia rosae, to glucosinolates and isothiocyanates. Chemoecology 16:209–218
Benson RB (1950) An introduction to the natural history of British sawflies. Trans Soc Brit Entomol 10:45–142
Bruce TJA, Wadhams LJ, Woodcock CM (2005) Insect host location: a volatile situation. Trends Plant Sci 10:269–274
Dötterl S, Füssel U, Jürgens A, Aas G (2005a) 1,4-Dimethoxybenzene, a floral scent compound in willows that attracts an oligolectic bee. J Chem Ecol 31:2993–2998
Dötterl S, Wolfe LM, Jürgens A (2005b) Qualitative and quantitative analyses of flower scent in Silene latifolia. Phytochemistry 66:203–213
Dötterl S, Jürgens A, Wolfe LM, Biere A (2009) Disease status and population origin effects on floral scent: potential consequences for oviposition and fruit predation in a complex interaction between a plant, fungus, and noctuid moth. J Chem Ecol 35:307–319
Finch S, Collier RH (2000) Host-plant selection by insects—a theory based on ‘appropriate/inappropriate landings’ by pest insects of cruciferous plants. Entomol Exp Appl 96:91–102
Füssel U, Dötterl S, Jürgens A, Aas G (2007) Inter- and intraspecific variation in floral scent in the genus Salix and its implication for pollination. J Chem Ecol 33:749–765
Kehl A, Aas G, Rambold G (2008) Genotypical and multiple phenotypical traits discriminate Salix × rubens Schrank clearly from its parent species. Plant Syst Evol 275:169–179
Kolehmainen J, Roininen H, Julkunen-Tiitto R, Tahvanainen J (1994) Importance of phenolic glucosides in host selection of shoot galling sawfly Euura amerinae on Salix pentandra. J Chem Ecol 20:2455–2466
Kopelke J-P (1998) Oviposition strategies of gall-making species of the sawfly genera Pontania, Euura and Phyllocolpa (Hymenoptera: Tenthredinidae: Nematinae). Entomol Gen 22:251–275
Mookherjee BD, Trenkle RW, Wilson RA (1990) The chemistry of flowers, fruits and spices: live vs. dead a new dimension in fragrance research. Pure Appl Chem 62:1357–1364
Roininen H, Price PW, Julkunen-Tiitto R, Tahvanainen J, Ikonen A (1999) Oviposition stimulant for a gall-inducing sawfly, Euura lasiolepis, on willow is a phenolic glycoside. J Chem Ecol 24:943–953
Soetens P, Rowell-Rahier M, Pasteels JM (1991) Influence of phenolglucosides and trichome density on the distribution of insect herbivores on willows. Entomol Exp Appl 59:175–187
Theis N (2006) Fragrance of Canada Thistle (Cirsium arvense) attracts both floral herbivores and pollinators. J Chem Ecol 32:917–927
Acknowledgments
Parts of the study were supported by the German Research Foundation DFG (Graduiertenkolleg 678). Ulrike Glück (formerly Füssel) provided flower scent samples of Salix fragilis.
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Kehl, A., Dötterl, S., Aas, G. et al. Is flower scent influencing host plant selection of leaf-galling sawflies (Hymenoptera, Tenthredinidae) on willows?. Chemoecology 20, 215–221 (2010). https://doi.org/10.1007/s00049-010-0050-6
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DOI: https://doi.org/10.1007/s00049-010-0050-6