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Oecologia

, Volume 136, Issue 4, pp 565–570 | Cite as

Nectarless flowers: ecological correlates and evolutionary stability

  • Juilee D. Thakar
  • Krushnamegh Kunte
  • Anisha K. Chauhan
  • Aparna V. Watve
  • Milind G. Watve
Plant Animal Interactions

Abstract

In animal-pollinated flowers, the pollinators cannot detect the presence of nectar before entering flowers, and therefore flowers may cheat by not producing nectar. An earlier model suggested that a mixed strategy of producing nectarful and nectarless flowers would be evolutionarily stable. Here we compare nectarless flowers as a cheating strategy with three competing hypotheses namely "visit-more-flowers", "cross-pollination enhancement" and "better contact". We collected field data on 28 species of plants to test some of the differential predictions of the hypotheses. Nectarless flowers were detected in 24 out of 28 plant species. Correlations of percent nectarless flowers with floral and ecological variables support the cheater flower hypothesis. We further model the cost-benefits of cheating and show that an evolutionary stable ratio of nectarless to nectarful flowers can be reached. The equilibrium ratio is mainly decided by factors associated with pollinator density and pollinator learning.

Keywords

Animal pollination Nectarless flowers Cheating Pollinator learning 

Notes

Acknowledgements

We thank K.N. Ganeshaiah, R. Uma Shaanker and Aadish Dani for useful discussions, and Ashwini Ghate for help in field work. We also thank G.A.C. Bell for his critical comments on an earlier draft of this manuscript.

References

  1. Bell G (1986) The evolution of empty flowers. J Theor Biol 118:253–258Google Scholar
  2. Brink DW, deWet JMJ (1980) Interpopulation variation in nectar production in Aconitum columbianum (Ranunculaceae). Oecologia 47:160–163Google Scholar
  3. Dukas R, Real LA (1993) Learning constraints and floral choice behaviour in bumble bees. Anim Behav 46:637–644CrossRefGoogle Scholar
  4. Feinsinger P (1978) Ecological interactions between plants and hummingbirds in a successional tropical community. Ecol Monogr 48:269–287Google Scholar
  5. Ferdy JB, Gouyon PH, Moret J, Godelle B (1998) Pollinator behavior and deceptive pollination: learning process and floral evolution. Am Natl 152:696–705CrossRefGoogle Scholar
  6. Gigord LDB, Macnair MR, Striteski M, Smithson A (2002) The potential for floral mimicry in rewardless orchids: an experimental study. Proc R Soc Lond B 269:1389–1395CrossRefPubMedGoogle Scholar
  7. Golubov J, Eguiarte LE, Mandujano MC, Lopez-Portillo J, Montana C (1999) Why be a honeyless honey mesquite? Reproduction and mating system of nectarful and nectarless individuals. Am J Bot 86:955–963Google Scholar
  8. Gumbert A, Kunze J (2001) Colour similarity to rewarding model plants affects pollination in a food deceptive orchid, Orchis boryi. Biol J Linn Soc 72:419–433Google Scholar
  9. Heinrich B (1975) Bee flowers: a hypothesis on flower variety and blooming times. Evolution 29:325–334Google Scholar
  10. Johnson SD (1994) Evidence for Batesian mimicry in a butterfly pollinated orchid. Biol J Linn Soc 53:91–104CrossRefGoogle Scholar
  11. Johnson SD (2000) Batesian mimicry in the non-rewarding orchid Disa pulchra, and its consequences for pollinator behaviour. Biol J Linn Soc 71:119–132CrossRefGoogle Scholar
  12. Kevan PG, Baker HG (1985) Insects as flower visitors and pollinators. Ann Rev Entomol 28:407–453Google Scholar
  13. Levin DA (1978) The origin of isolating mechanisms in flowering plants. Evol Biol 11:185–317Google Scholar
  14. Pleasants JM, Chaplin SJ (1983) Nectar production rates of Asclepias quadrifolia: causes and consequences of individual variation. Oecologia 59:232–238Google Scholar
  15. Pyke GH (1991) What does it cost the plant to produce floral nectar? Nature 350:58–59Google Scholar
  16. Smithson A, Gigord LDB (2001) Are there fitness advantages in being a rewardless orchid? Reward supplementation experiments with Barlia robertiana. Proc R Soc Lond B 268:1435–1441Google Scholar
  17. Smithson A, MacNair MR (1997) Negative frequency dependent selection by pollinators on artificial flowers without rewards. Evolution 51:715–723Google Scholar
  18. Southwick EE (1987) Photosynthate allocation to floral nectar: a neglected energy investment. Ecology 65:1775–1779Google Scholar
  19. Waser NM (1986) Flower constancy: definition, cause and measurement. Am Nat 127:593–603CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • Juilee D. Thakar
    • 1
  • Krushnamegh Kunte
    • 1
  • Anisha K. Chauhan
    • 1
  • Aparna V. Watve
    • 1
  • Milind G. Watve
    • 1
  1. 1.Life Research FoundationPuneIndia

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