Evolutionary Ecology

, Volume 29, Issue 3, pp 405–417 | Cite as

Nectar palatability can selectively filter bird and insect visitors to coral tree flowers

  • Susan W. Nicolson
  • Sara Lerch-Henning
  • Megan Welsford
  • Steven D. JohnsonEmail author
Original Paper


Secondary compounds in nectar may play a decisive role in determining the spectrum of floral visitors on plants. Flowers of the African coral tree Erythrina caffra are visited mainly by generalist passerine nectarivores, such as weavers and bulbuls. As the nectar of this species tastes very bitter to humans, it was hypothesized that secondary compounds may repel sunbirds and honeybees which are common in the same habitats yet seldom consume the nectar. We conducted choice tests using fresh nectar and both sucrose and hexose (glucose/fructose) solutions of the same concentration as the nectar. White-bellied Sunbirds (Cinnyris talatala) were repelled by nectar of both E. caffra and a related species Erythrina lysistemon, but Dark-capped Bulbuls (Pycnonotus tricolor) did not discriminate between the Erythrina nectar and control sugar solution in terms of amounts consumed. Honeybees (Apis mellifera scutellata) probed exposed droplets of E. caffra nectar and a control sugar solution at the same rate, suggesting that there is no volatile deterrent, but they immediately withdrew their proboscis far more often from the droplets of Erythrina nectar than they did from the sugar solution, suggesting that they find Erythrina nectar distasteful. These results contribute to a growing awareness that non-sugar components of nectar can play important functional roles in plant pollination systems.


Bird pollination Bitter nectar Dilute nectar Erythrina Generalist nectarivores 



This research was funded by the South African National Research Foundation (NRF). We thank the Gauteng Directorate of Nature Conservation and Jan Celliers Park for permission to capture and house the birds. All bird care procedures and experimental protocols followed the institutional regulations of the University of Pretoria (EC022-09).


  1. Adler LS (2000) The ecological significance of toxic nectar. Oikos 91:409–420CrossRefGoogle Scholar
  2. Adler LS, Irwin RE (2012) Nectar alkaloids decrease pollination and female reproduction in a native plant. Oecologia 168:1033–1041CrossRefPubMedGoogle Scholar
  3. Adler LS, Seifert MG, Wink M, Morse GE (2012) Reliance on pollinators predicts defensive chemistry across tobacco species. Ecol Lett 15:1140–1148CrossRefPubMedGoogle Scholar
  4. Baker I, Baker HG (1982) Some chemical constituents of floral nectars of Erythrina in relation to pollinators and systematics. Allertonia 3:25–37Google Scholar
  5. Botes C, Johnson SD, Cowling RA (2008) Coexistence of succulent tree aloes: partitioning of bird pollinators by floral traits and flowering phenology. Oikos 117:875–882CrossRefGoogle Scholar
  6. Bronstein JL (2001) The exploitation of mutualisms. Ecol Lett 4:277–287CrossRefGoogle Scholar
  7. Brouat C, Garcia N, Andary C, McKey D (2001) Plant lock and ant key: pairwise coevolution of an exclusion filter in an ant-plant mutualism. Proc R Soc B 268:2131–2141CrossRefPubMedCentralPubMedGoogle Scholar
  8. Brown M, Downs CT, Johnson SD (2010a) Sugar preferences and digestive efficiency in an opportunistic avian nectarivore, the Dark-capped Bulbul Pycnonotus tricolor. J Ornithol 151:637–643CrossRefGoogle Scholar
  9. Brown M, Downs CT, Johnson SD (2010b) Sugar preferences of a generalist nonpasserine flower visitor, the African Speckled Mousebird (Colius striatus). Auk 127:781–786CrossRefGoogle Scholar
  10. Bruneau A (1997) Evolution and homology of bird pollination syndromes in Erythrina (Leguminosae). Am J Bot 84:54–71CrossRefGoogle Scholar
  11. Cotton PA (2001) The behavior and interactions of birds visiting Erythrina fusca flowers in the Colombian Amazon. Biotropica 33:662–669CrossRefGoogle Scholar
  12. Cruden RW, Toledo VM (1977) Oriole pollination of Erythrina breviflora (Leguminosae): evidence for a polytypic view of ornithophily. Plant Syst Evol 126:393–403CrossRefGoogle Scholar
  13. Etcheverry AV, Trucco Alemán CE (2005) Reproductive biology of Erythrina falcata (Fabaceae: Papilionoideae). Biotropica 37:54–63CrossRefGoogle Scholar
  14. Feinsinger P, Linhart YB, Swarm LA, Wolfe JA (1979) Aspects of the pollination biology of three Erythrina species on Trinidad and Tobago. Ann Mo Bot Gard 66:451–471CrossRefGoogle Scholar
  15. Fleming PA, Hartman Bakken B, Lotz CN, Nicolson SW (2004) Concentration and temperature effects on sugar intake and preferences in a sunbird and a hummingbird. Funct Ecol 18:223–232CrossRefGoogle Scholar
  16. Galetto L, Bernardello G, Isele IC, Vesprini J, Speroni G, Berduc A (2000) Reproductive biology of Erythrina crista-galli (Fabaceae). Ann Mo Bot Gard 87:127–145CrossRefGoogle Scholar
  17. Gardener MC, Gillman MP (2002) The taste of nectar—a neglected area of pollination ecology. Oikos 98:552–557CrossRefGoogle Scholar
  18. Gegear RJ, Manson J, Thomson J (2007) Ecological context influences pollinator deterrance by alkaloids in floral nectar. Ecol Lett 10:375–382CrossRefPubMedGoogle Scholar
  19. Hargreaves AL, Harder LD, Johnson SD (2009) Consumptive emasculation: the ecological and evolutionary implications of pollen theft. Biol Rev 84:259–276CrossRefPubMedGoogle Scholar
  20. Hockey PAR, Dean WRJ, Ryan PG (eds) (2005) Roberts—birds of Southern Africa, VII edn. The Trustees of the John Voelcker Bird Book Fund, Cape TownGoogle Scholar
  21. Jacot Guillarmod A, Jubb RA, Skead CJ (1979) Field studies of six Southern African species of Erythrina. Ann Mo Bot Gard 66:521–527CrossRefGoogle Scholar
  22. Johnson SD, Nicolson SW (2008) Evolutionary associations between nectar properties and specificity in bird pollination systems. Biol Lett 4:49–52CrossRefPubMedCentralPubMedGoogle Scholar
  23. Johnson SD, Hargreaves AL, Brown M (2006) Dark bitter-tasting nectar functions as a filter of flower visitors in a bird-pollinated plant. Ecology 87:2709–2716CrossRefPubMedGoogle Scholar
  24. Juma BF, Majinda RRT (2004) Erythrinaline alkaloids from the flowers and pods of Erythrina lysistemon and their DPPH radical scavenging properties. Phytochemistry 65:1397–1404CrossRefPubMedGoogle Scholar
  25. Kessler D, Baldwin IT (2007) Making sense of nectar scents: the effects of nectar secondary metabolites on floral visitors of Nicotiana attenuata. Plant Journal 49:840–854CrossRefPubMedGoogle Scholar
  26. Latham P (2001) Beekeeping and some honeybee plants in Umalila. Southern Tanzania. In, Bees for DevelopmentGoogle Scholar
  27. Lerch-Henning S, Nicolson SW (2013) Bird pollinators differ in their tolerance of a nectar alkaloid. J Avian Biol 44:408–416CrossRefGoogle Scholar
  28. Leseigneur CDC, Verburgt L, Nicolson SW (2007) Whitebellied sunbirds (Nectarinia talatala, Nectariniidae) do not prefer artificial nectar containing amino acids. J Comp Physiol B 177:679–685CrossRefPubMedGoogle Scholar
  29. Lis H, Joubert FJ, Sharon N (1985) Isolation and properties of n-acetyllactosamine-specific lectins from nine Erthyrina species. Phytochemistry 24:2803–2809CrossRefGoogle Scholar
  30. Napier KR, McWhorter TJ, Nicolson SW, Fleming PA (2013) Sugar preferences of avian nectarivores are correlated with intestinal sucrase activity. Physiol Biochem Zool 86:499–514CrossRefPubMedGoogle Scholar
  31. Neill DA (1987) Trapliners in the trees: hummingbird pollination of Erythrina sect. Erythrina (Leguminosae: Papilionoideae). Ann Mo Bot Gard 74:27–41CrossRefGoogle Scholar
  32. Nicolson SW (2007) Amino acid concentrations in the nectars of southern African bird-pollinated flowers, especially Aloe and Erythrina. J Chem Ecol 33:1707–1720CrossRefPubMedGoogle Scholar
  33. Odendaal TC, Brown M, Downs CT, Johnson SD (2010) Sugar preferences and digestive efficiency of the village weaver: a generalist avian pollinator of African plants. J Exp Biol 213:2531–2535CrossRefPubMedGoogle Scholar
  34. Peumans WJ, Smeets K, Van Nerum K, Van Leuven F, Van Damme EJM (1997) Lectin and alliinase are the predominant proteins in nectar from leek (Allium porrum L.) flowers. Planta 201:298–302CrossRefPubMedGoogle Scholar
  35. Raju AJS, Rao SP (2004) Passerine bird pollination and fruiting behaviour in a dry season blooming tree species, Erythrina suberosa Roxb. (Fabaceae) in the Eastern Ghats forests India. Ornithol Sci 3:139–144CrossRefGoogle Scholar
  36. Rodriguez-Girones MA, Santamaria L (2005) Resource partitioning among flower visitors and evolution of nectar concealment in multi-species communities. Proc R Soc B Biol Sci 272:187–192CrossRefGoogle Scholar
  37. Romeo JT, Bell EA (1974) Distribution of amino acids and certain alkaloids in Erythrina species. Lloydia 37:543–568PubMedGoogle Scholar
  38. Shuttleworth A, Johnson SD (2009) The importance of scent and nectar filters in a specialized wasp-pollination system. Funct Ecol 23:931–940CrossRefGoogle Scholar
  39. Stephenson AG (1982) Iridoid glycosides in the nectar of Catalpa speciosa are unpalatable to nectar thieves. J Chem Ecol 8:1025–1034CrossRefPubMedGoogle Scholar
  40. Symes CT, McKechnie AE, Nicolson SW, Woodborne SM (2011) The nutritional significance of a winter-flowering succulent for opportunistic avian nectarivores. Ibis 153:110–121CrossRefGoogle Scholar
  41. Tchuenguem Fohouo F-N, Tope SF, Mbianda AP, Messi J, Brückner D (2010) Foraging behaviour of Apis mellifera adansonii (Hymenoptera: Apidae) on Combretum nigricans, Erythrina sigmoidea, Lannea kerstingii and Vernonia amygdalina flowers at Dang (Ngaoundéré, Cameroon). Int J Trop Insect Sci 30:40–47CrossRefGoogle Scholar
  42. Willmer PG et al (2009) Floral volatiles controlling ant behaviour. Funct Ecol 23:888–900CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Susan W. Nicolson
    • 1
  • Sara Lerch-Henning
    • 1
  • Megan Welsford
    • 2
  • Steven D. Johnson
    • 2
    Email author
  1. 1.Department of Zoology and EntomologyUniversity of PretoriaHatfieldSouth Africa
  2. 2.School of Life SciencesUniversity of KwaZulu NatalScottsville, PietermaritzburgSouth Africa

Personalised recommendations