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Private Channel (private + channel)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Private channel: a single unusual compound assures specific pollinator attraction in Ficus semicordata

FUNCTIONAL ECOLOGY, Issue 5 2009
Chun Chen
Summary 1.,Floral scents have been suggested to play a key role in the obligate pollination mutualism between figs and fig wasps. However, few studies have determined whether pollinator-attractive compounds could alone assure species-specificity (,private channel'), or whether specificity is mediated by more complex ,floral filters', of which scent is only one component. 2.,We examined changes in the floral volatile compounds of Ficus semicordata, a dioecious fig species, during and after pollination using headspace collection and compound identification by Gas Chromatography/Mass Spectrometry (GC/MS). One benzenoid compound, 4-methylanisole, was strongly predominant (94,98%) among the volatile compounds emitted by both male and female receptive figs of F. semicordata, whereas it was totally absent in the volatiles emitted by figs 4 days after pollination, as well as in receptive-stage volatiles emitted by two other sympatric fig species, Ficus racemosa and Ficus hispida. 3.,Bioassays using the specific pollinator of F. semicordata, Ceratosolen gravelyi, in a Y-tube olfactometer showed that 4-methylanisole was attractive to C. gravelyi in a wide range of concentrations (from 1·22 × 10,2 ng/100 ,L to 1·22 × 106ng/100,L). Moreover, chemical blends lacking 4-methylanisole were unattractive to C. gravelyi. These non-active odour sources included volatile compounds emitted by receptive figs of the two other sympatric fig species and volatiles of F. semicordata post-pollination figs. 4.,All these results suggest that 4-methylanisole is the main signal compound in the floral scent of F. semicordata that attracts its obligate pollinator to the host figs at the precise stage required for pollination and oviposition. Furthermore, the high proportion of 4-methylanisole in the odours of receptive figs of both sexes was consistent with the hypothesis of chemical mimicry in dioecious figs. 5.,A simple signal comprised of one compound that is unusual among Ficus and that is an infrequent, usually minor, component of other floral odours, may thus function as a private channel in this specialized obligate mutualism. [source]

Chemical ecology of obligate pollination mutualisms: testing the ,private channel' hypothesis in the Breynia,Epicephala association

NEW PHYTOLOGIST, Issue 4 2010
Glenn P. Svensson
Summary ,Obligate mutualisms involving actively pollinating seed predators are among the most remarkable insect,plant relationships known, yet almost nothing is known about the chemistry of pollinator attraction in these systems. The extreme species specificity observed in these mutualisms may be maintained by specific chemical compounds through ,private channels'. Here, we tested this hypothesis using the monoecious Breynia vitis-idaea and its host-specific Epicephala pollinator as a model. ,Headspace samples were collected from both male and female flowers of the host. Gas chromatography with electroantennographic detection (GC-EAD), coupled gas chromatography,mass spectrometry, and olfactometer bioassays were used to identify the floral compounds acting as the pollinator attractant. ,Male and female flowers of B. vitis-idaea produced similar sets of general floral compounds, but in different ratios, and male flowers emitted significantly more scent than female flowers. A mixture of 2-phenylethyl alcohol and 2-phenylacetonitrile, the two most abundant compounds in male flowers, was as attractive to female moths as the male flower sample, although the individual compounds were slightly less attractive when tested separately. ,Data on the floral scent signals mediating obligate mutualisms involving active pollination are still very limited. We show that system-specific chemistry is not necessary for efficient host location by exclusive pollinators in these tightly coevolved mutualisms. [source]