Bee Flowers: A Hypothesis on Flower Variety and Blooming Times

Heinrich, Bernd

doi:10.1111/j.1558-5646.1975.tb00212.x

Cited by 187 publications

(182 citation statements)

References 43 publications

Supporting

Mentioning

164

Contrasting

Unclassified

Order By: Relevance

“…Character displacement is thought to occur as a result of selection against interspecific pollen transfer which may lead to hybridization, and against competition for pollinators. Competition for pollinators and avoidance of interspecific pollen transfer are proposed as selective forces in several other studies (Mosquin, 1971;Gentry, 1974Gentry, , 1976Heinrich, 1975;Reader, 1975;Stiles, 1975;Waser, 1978 a, b;and others) but evidence for such competition has only been provided by Waser (1978 a, b) between Delphinium nelsoni and Ipomopsis aggregata, and by Zimmerman (1980) between individuals of Polemoniumfoliosissimum. Some additional evidence comes from competition between native plants and crops (Free, 1970).…”

Section: Introductionmentioning

confidence: 99%

COMPETITION FOR POLLINATORS IN THE ECOLOGY OF CENTAUREA SCABIOSA L. AND CENTAUREA NIGRA L.

Lack

1982

New Phytologist

View full text Add to dashboard Cite

SUMMARYIf competition for pollinators is an important influence on populations of Centaurea scabiosa and C. nigra sensu lato one of the characters most likely to be affected is flowering time. Observations were made on the flowering period of several populations of the two species growing sympatrically and in isolation, and on plants from these and further populations transplanted into the Botanic Garden.Conclusions from the study are: (1) Where C. scabiosa and C. nigra grow sympatrically, C. nigra flowers slightly later than C scabiosa but there is a considerable period of overlap. The large range of flowering time seen in C. nigra may be partly attributable to differences between ssp. nigra and ssp. nemoralis and hybridization between them, but local ecological factors are important influences on some populations. Competition for pollinators between C scabiosa and C. nigra may maintain the difference in flowering time between the two species in some areas.

show abstract

Section: Introductionmentioning

confidence: 99%

COMPETITION FOR POLLINATORS IN THE ECOLOGY OF CENTAUREA SCABIOSA L. AND CENTAUREA NIGRA L.

Lack

1982

New Phytologist

View full text Add to dashboard Cite

show abstract

“…The hypothesis that variation in flower characteristics in non-food-rewarding flowers inhibits the formation of a search image by the pollinator (Heinrich 1975;Nilsson 1980;Ackerman 1986) and interferes with its associative learning process was tested by Moya and Ackerman (1993), who found high levels of flower fragrance variation in the nectarless, moth-pollinated orchid Epidendrum ciliare. Intraspecific variation in floral fragrances has also been documented for nectar-producing orchids, including Platanthera stricta (Patt et al 1989) and P. bifolia (Tollsten and Bergströ m 1989).…”

mentioning

confidence: 99%

Evolution of Reproductive Strategies in the Sexually Deceptive Orchid Ophrys Sphegodes: How Does Flower-Specific Variation of Odor Signals Influence Reproductive Success?

et al. 2000

View full text Add to dashboard Cite

Abstract. The orchid Ophrys sphegodes Miller is pollinated by sexually excited males of the solitary bee Andrena nigroaenea, which are lured to the flowers by visual cues and volatile semiochemicals. In O. sphegodes, visits by pollinators are rare. Because of this low frequency of pollination, one would expect the evolution of strategies that increase the chance that males will visit more than one flower on the same plant; this would increase the number of pollination events on a plant and therefore the number of seeds produced. Using gas chromatography-mass spectrometry (GC-MS) analyses, we identified more than 100 compounds in the odor bouquets of labellum extracts from O. sphegodes; 24 compounds were found to be biologically active in male olfactory receptors based on gas chromatography with electroantennographic detection (GC-EAD). Gas chromatography (GC) analyses of odors from individual flowers showed less intraspecific variation in the odor bouquets of the biologically active compounds as compared to nonactive compounds. This can be explained by a higher selective pressure on the pollinator-attracting communication signal. Furthermore, we found a characteristic variation in the GC-EAD active esters and aldehydes among flowers of different stem positions within an inflorescence and in the n-alkanes and n-alkenes among plants from different populations. In our behavioral field tests, we showed that male bees learn the odor bouquets of individual flowers during mating attempts and recognize them in later encounters. Bees thereby avoid trying to mate with flowers they have visited previously, but do not avoid other flowers either of a different or the same plant. By varying the relative proportions of saturated esters and aldehydes between flowers of different stem positions, we demonstrated that a plant may take advantage of the learning abilities of the pollinators and influence flower visitation behavior. Sixty-seven percent of the males that visited one flower in an inflorescence returned to visit a second flower of the same inflorescence. However, geitonogamy is prevented and the likelihood of cross-fertilization is enhanced by the time required for the pollinium deposited on the pollinator to complete its bending movement, which is necessary for pollination to occur. Cross-fertilization is furthermore enhanced by the high degree of odor variation between plants. This variation minimizes learned avoidance of the flowers and increases the likelihood that a given pollinator would visit several to many different plants within a population.

show abstract

“…Does the absence of reward play a role in the maintenance of these corolla-color polymorphisms? It has been suggested that both the rewardless characteristic of the plant and the naivete of pollinators may contribute to their maintenance (7,11,12). Rewardless orchids are usually pollinated by newly emerged naive insects, typically bumblebees in Europe (6).…”

mentioning

confidence: 99%

Negative frequency-dependent selection maintains a dramatic flower color polymorphism in the rewardless orchid Dactylorhiza sambucina (L.) Soò

Gigord

Macnair²,

Smithson³

2001

Proc. Natl. Acad. Sci. U.S.A.

333

279

View full text Add to dashboard Cite

The orchid Dactylorhiza sambucina shows a stable and dramatic flower-color polymorphism, with both yellow-and purple-flowered individuals present in natural populations throughout the range of the species in Europe. The evolutionary significance of flower-color polymorphisms found in many rewardless orchid species has been discussed at length, but the mechanisms responsible for their maintenance remain unclear. Laboratory experiments have suggested that behavioral responses by pollinators to lack of reward availability might result in a reproductive advantage for rare-color morphs. Consequently, we performed an experiment varying the relative frequency of the two color morphs of D. sambucina to test whether rare morph advantage acted in the natural habitat of the species. We show here clear evidence from this manipulative experiment that rare-color morphs have reproductive advantage through male and female components. This is the first demonstration, to our knowledge, that negative frequency-dependent selection through pollinator preference for rare morphs can cause the maintenance of a flower-color polymorphism.

show abstract

Bee Flowers: A Hypothesis on Flower Variety and Blooming Times

Cited by 187 publications

References 43 publications

COMPETITION FOR POLLINATORS IN THE ECOLOGY OF CENTAUREA SCABIOSA L. AND CENTAUREA NIGRA L.

COMPETITION FOR POLLINATORS IN THE ECOLOGY OF CENTAUREA SCABIOSA L. AND CENTAUREA NIGRA L.

Evolution of Reproductive Strategies in the Sexually Deceptive Orchid Ophrys Sphegodes: How Does Flower-Specific Variation of Odor Signals Influence Reproductive Success?

Negative frequency-dependent selection maintains a dramatic flower color polymorphism in the rewardless orchid Dactylorhiza sambucina (L.) Soò

Contact Info

Product

Resources

About