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  • 1
    Electronic Resource
    Electronic Resource
    Orchid pollination by sexual swindle (1999)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 399 (1999), S. 421-421 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The flowers of Ophrys orchids mimic receptive females of usually only one pollinator species. Males of this species are attracted primarily by the odour of a flower and transfer the pollinia during so-called ‘pseudocopulations’ with the flowers. We have found that flowers of O. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/20829
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  • 2
    Electronic Resource
    Electronic Resource
    Caste- and colony-specific chemical signals on eggs of the bumble bee, Bombus terrestris L. (Hymenoptera: Apidae) (1999)
    Springer
    Chemoecology 9 (1999), S. 119-126 
    Details
    ISSN: 1423-0445
    Keywords: Key words. egg volatiles — caste- and colony-specific odour — chemical analysis — Dufour's gland pheromones — hydrocarbons — chemical communication — Hymenoptera — Apidae —Bombus terrestris L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary. In the bumble bee, Bombus terrestris L., we investigated whether a chemical signal corresponding to the egg-marking in honey bees occurs, and whether the pattern of volatiles encodes caste-, colony- or even individual-specific information. Volatile compounds were obtained by surface extraction of individual eggs with pentane. The resulting complex mixtures were analysed by gas chromatography and mass spectrometry. Major classes of identified compounds were n-alkanes, n-alkenes and n-alkadienes comprising approximately 95% of the extracted volatile material. In addition, small amounts of methyl-branched alkanes, ethyl esters, methyl esters, wax type esters and acetates were present. Eggs produced by queens and individual workers showed significantly different compositions of volatiles. Furthermore, the volatile patterns were found to be colony-specific. Egg-odours contained all compounds identified in the Dufour’s glands and some additional components. Therefore, females very likely mark eggs with excretions of Dufour’s gland, however, other glands may also be involved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s000490050042
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  • 3
    Electronic Resource
    Electronic Resource
    Variation of Floral Scent Emission and Postpollination Changes in Individual Flowers of Ophrys sphegodes Subsp. sphegodes (1997)
    Springer
    Journal of chemical ecology 23 (1997), S. 2881-2895 
    Details
    ISSN: 1573-1561
    Keywords: Ophrys sphegodes subsp sphegodes ; Andrena nigroaenea ; floral scent ; floral semiochemicals ; headspace sorption ; postpollination changes ; nocturnal scent emission
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We investigated the scent composition of individual flowers of Ophrys sphegodes, its alteration following pollination, and of picked flowers by day and at night. Odor samples were collected by headspace sorption and analyzed by gas chromatography and mass spectrometry. To evaluate the function of postpollination odor changes, we carried out behavioral tests on the pollinator Andrena nigroaenea with pollinated and unpollinated flowers. We identified 27 volatiles in the flower scents. Aldehydes and alkanes were most frequently found. Aldehydes were the most abundant class of compounds (40–50%). When flowers were picked, they emitted significantly lower total amounts of volatiles than unpicked flowers, and their odor bouquets were significantly different. Comparison of scents released by day and at night showed no decrease in scent emission during nighttime, but the odor bouquets were significantly different. Pollinated flowers produced significantly different odor bouquets, and the total amount of scent emitted two to four days after pollination was significantly lower compared with unpollinated flowers. In addition, behavioral tests with A. nigroaenea males showed that flowers were significantly less attractive three days after pollination. This reduced attractiveness is hypothesized to guide pollinators to the unpollinated flowers within an inflorescence, and thus increase the reproductive success of the plant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022527430163
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  • 4
    Electronic Resource
    Electronic Resource
    Post-mating odor in females of the solitary bee, Andrena nigroaenea (Apoidea, Andrenidae), inhibits male mating behavior (2000)
    Springer
    Behavioral ecology and sociobiology 48 (2000), S. 303-307 
    Details
    ISSN: 1432-0762
    Keywords: Key words Post-mating odor change ; Gas chromatography-electroantennographic detection ; Farnesol ; Farnesyl hexanoate ; Sexual selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  We investigated odor changes and their behavioral significance in the solitary, ground-nesting bee Andrena nigroaenea. We used gas chromatography with electroantennographic detection and performed behavioral tests with males in the field using natural odor samples and synthetic compounds. We found that only cuticle extracts of young females elicited copulation attempts in the males. We demonstrated that among the 17 compounds which triggered electroantennographic responses, all-trans-farnesyl hexanoate and all-trans-farnesol were significantly more abundant in unattractive cuticle extracts of A. nigroaenea females. Dufour’s gland extracts of these females also contained greater amounts of both compounds. In bioassays using synthetic farnesyl hexanoate and farnesol we found that these compounds inhibit copulation behavior in the males. Farnesyl hexanoate is probably synthesized in Dufour’s gland and used by females for lining brood cells. We interpret the semiochemical function of farnesyl hexanoate and its precursor farnesol to have evolved secondarily. As an outcome of sexual selection, it facilitates the discrimination by males of receptive females from nesting and thus already mated individuals. The dual function of these compounds represents an elegant parsimony in the chemical communication system of this insect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002650000241
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  • 5
    Electronic Resource
    Electronic Resource
    Kin-based male mating preferences in two species of halictine bee (1987)
    Springer
    Behavioral ecology and sociobiology 20 (1987), S. 313-318 
    Details
    ISSN: 1432-0762
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In both of the social bee species Lasioglossum (Dialictus) zephyrum and Lasioglossum (Evylaeus) malachurum (Hymenoptera: Halictidae), males are shown to be attracted to females in field experiments by a pheromone which covaries among female relatives. Females sampled from a nesting aggregation other than the one in which the tested males occur are slightly more attractive than females from the males' own aggregation, and always significantly more attractive than females whose pheromones have been extracted. Furthermore, in L. malachurum experience with a female alters the response of the males towards that female and towards her nestmates (most probably close relatives) in further encounters, but does not alter the males' responses towards females who were non-nestmates of the experienced one. These data indicate that some form of learning of female kin-identity takes place in adult males, and influences the mating system. How males may integrate kinship information into a mating strategy is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300676
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  • 6
    Electronic Resource
    Electronic Resource
    Mating expenditures reduced via female sex pheromone modulation in the primitively eusocial halictine bee, Lasioglossum (Evylaeus) malachurum (Hymenoptera: Halictidae) (1999)
    Springer
    Behavioral ecology and sociobiology 45 (1999), S. 95-106 
    Details
    ISSN: 1432-0762
    Keywords: Key wordsLasioglossum (Evylaeus) malachurum ; Sweat bee ; Sex pheromone modulation ; Mating behavior ; Chemical analyses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The present paper reports on behavioral experiments and gas chromatographic analysis of chemical communication in the mating biology of the primitively eusocial sweat bee Lasioglossum (Evylaeus) malachurum. In a dual-choice experiment, a female made odorless was significantly less attractive than an untreated one. Attraction in L. (Evylaeus) malachurum is therefore mediated by a female-produced sex pheromone. Further bioassays showed that unmated gynes are more attractive to males than mated ones. Males are able to differentiate between the two groups of females as little as 3 h after mating. Biotests with different samples obtained from attractive gynes showed surface extracts to be most attractive. Behavioral tests with synthetic copies of the compounds identified as cuticular constituents of virgin gynes were highly attractive to males; the volatile bouquets consisting of n-alkanes, n-alkenes and iso- pentenyl esters of unsaturated fatty acids were the most attractive samples. Isopentenyl esters of unsaturated fatty acids were the key compounds in inducing male inspections as well as stimulating pounces and copulatory attempts. Virgin and nesting gynes differed clearly in the relative and absolute amounts of the volatiles on the cuticle. The total amount of volatiles was significantly higher in virgin gynes and decreased in breeding queens. Hydrocarbons were the dominant group of compounds in both groups of females. The relative amounts of the wax-type ester, hexadecyl oleate, iso- pentenyl esters, and a hitherto unidentified steroid were higher in attractive virgin gynes, while the relative proportions of hydrocarbons and lactones dominated in nesting queens. The site of sex pheromone production in attractive young L. (Evylaeus) malachurum gynes remains unknown. Head glands or Dufour's gland secretions may be involved. Another possible source of the `active principle' found among the cuticular lipids could be glandular cells of the epidermis. The significance of modulation of female sex pheromone composition is discussed in terms of a reduction in mating expenditures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002650050543
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