Arthropod-Plant Interactions

, Volume 2, Issue 2, pp 117–123 | Cite as

Variability in nectar production and standing crop, and their relation to pollinator visits in a Mediterranean shrub

Original Paper

Abstract

Nectar standing crops in flowers within an individual plant are often highly variable. This variability may be a by-product of the foraging activity of insect pollinators. Alternatively, plants may be selected to produce highly variable rewards to reduce consecutive visitation by risk-averse pollinators, thus diminishing within-plant pollen transfer. This study evaluated the roles of pollinator control vs. plant control over nectar variability in the bee-pollinated shrub Rosmarinus officinalis L. (Lamiaceae). We sampled nectar production, standing crop and pollinator visits in three shrubs of one population over 17 days during one blooming season. Nectar production rates were highly variable (CV = 1.48), and increased after rainy days. Nectar standing crops were even more variable (CV = 2.16), decreased with increasing temperatures, and increased with time since the last rain. Pollinator visit rates decreased with variability in nectar standing crops, increased with flower number per shrub, and were unaffected by variability in nectar production rates. Repeated sampling of marked flowers revealed no correlation between their nectar standing crops and production rates. These findings support the role of reward variance in reducing pollinator visits, but suggest that plants are not in complete control of this variability. Rather, plant-generated variability can be modified by intensive foraging activity of pollinators. Such pollinator control over nectar variability is likely to reduce the selective advantage of plant-generated reward variation.

Keywords

Geitonogamy Honeybee Rosmarinus officinalis Nectar variability Pollination 

Notes

Acknowledgements

The field work was supported by the Jewish National Fund. Data analysis and writing were supported by the research group on Evolution and Game Theory at the Institute of Advanced Studies, The Hebrew University. Tom de Jong commented on the manuscript. The experiments comply with the current laws of the State of Israel.

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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of Life SciencesAchva CollegeShikmimIsrael
  2. 2.Department of BiologyUniversity of Haifa – OranimTivonIsrael
  3. 3.Department of EntomologyAgricultural Research OrganizationBet DaganIsrael
  4. 4.Department of Evolution, Systematics & EcologyThe Hebrew UniversityJerusalemIsrael
  5. 5.Center for RationalityThe Hebrew UniversityJerusalemIsrael

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