Limited ability of Palestine Sunbirds Nectarinia osea to cope with pyridine alkaloids in nectar of Tree Tobacco Nicotiana glauca

Authors

  • H. TADMOR-MELAMED,

    1. Department of Biology, University of Haifa at Oranim, Faculty of Science and Science Education, Tivon 36006, Israel,
    2. Department of Animal Science, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel, and
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  • S. MARKMAN,

    1. Department of Biology, University of Haifa at Oranim, Faculty of Science and Science Education, Tivon 36006, Israel,
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    • *

      Present address: School of Biosciences, Main Building, Park Place, Cardiff University, Cardiff CF10 3TL, UK.

  • A. ARIELI,

    1. Department of Animal Science, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel, and
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  • M. DISTL,

    1. Institute für Pharmazie und Molekulare Biotechnologie (IPMB), Universität Heidelberg, Abt. Biologie, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
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  • M. WINK,

    1. Institute für Pharmazie und Molekulare Biotechnologie (IPMB), Universität Heidelberg, Abt. Biologie, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
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  • I. IZHAKI

    Corresponding author
    1. Department of Biology, University of Haifa at Oranim, Faculty of Science and Science Education, Tivon 36006, Israel,
      †Author to whom correspondence should be addressed. E-mail: izhaki@research.haifa.ac.il
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†Author to whom correspondence should be addressed. E-mail: izhaki@research.haifa.ac.il

Summary

  • 1Secondary compounds are common in floral nectar but their relative effects on nectar consumption and utilization in nectarivorous birds are unclear.
  • 2We studied the effect of two pyridine alkaloids, nicotine and anabasine, present in Tree Tobacco (Nicotiana glauca) nectar, on food consumption, gut transit time and sugar assimilation efficiency of the Palestine Sunbird (Nectarinia osea), a pollinator of N. glauca in east Mediterranean ecosystems.
  • 3Sunbirds demonstrated dose-dependent deterrence; they were not deterred by the lowest natural concentrations of these alkaloids in nectar (0·1 ppm nicotine and 0·6 ppm anabasine) but they were significantly deterred by the average concentrations detected in nectar (0·5 ppm nicotine and 5 ppm anabasine).
  • 4The two pyridine alkaloids reduced gut transit time (by 30–42%) and sugar assimilation efficiency (by 9–17%) compared with the control alkaloid-free diet.
  • 5Sunbirds are able to cope with low, but not average, concentrations of nicotine and anabasine in N. glauca nectar. If sunbirds are efficient pollinators of N. glauca they may induce selection on it to reduce pyridine alkaloid production in the nectar. Alternatively, high concentrations in some N. glauca plants may lead the birds to visit more plants with lower alkaloid concentrations. Hence, they will be more efficient pollinators, especially if other nectar-producing plants are scarce.

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