Abstract
The floral nectar ofCatalpa speciosa has a chemical mechanism that limits thievery. A bioassay employing sphingid larvae,Ceratomia catalpae, shows that catalpa iridoid glycosides are present in the floral nectar. When potential nectar thieves are fed nectar, a sucrose solution of identical concentration, or a sucrose solution plus 0.4% catalpol and 0.4% catalposide (catalpa iridoids), the thieves drink significantly more of the pure sucrose solution than either of the other two sugar sources. Those thieves that drink either the nectar or the sucrose solution plus catalpa iridoids develop behavioral abnormalities including regurgitation and loss of locomotion. The response of the potential nectar thieves to nectar or the sucrose solution plus catalpa iridoids cannot be distinguished by the amount consumed or by their behavior. The legitimate diurnal pollinators ofC. speciosa are not affected by the iridoid glycosides.
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References
Baker, H.G. 1978. Chemical aspects of the pollination of woody plants in the tropics, pp. 57–82,in P.B. Tomlinson, and M. Zimmerman (eds.). Tropical Trees as Living Systems. Cambridge University Press, New York.
Baker, H.G., andBaker, I. 1975. Studies of nectar-constituents and pollinator plant coevolution, pp. 100–140,in L.E. Gilbert and P.H. Raven (eds.). Coevolution of Plants and Animals. University of Texas Press, Austin.
Baker, H.G., Opler, P.A., andBaker, I. 1978. A comparison of the amino acid complements of floral and extrafloral nectars.Bot. Gaz. 139:322–332.
Bobbitt, J.M., Schmid, H., andAfrica, T.B. 1961. Catalpa glycosides. I. The characterization of catalposide.J. Org. Chem. 26:3090–3094.
Bobbitt, J.M., Spiggle, D.W., Mahboob, S., Schmid, H., andVon Philipsborn, W. 1966. Catalpa glycosides. III. The structure of catalposide.J. Org. Chem. 31:500–506.
Bobbitt, J.M., Kiely, D.E., Lam, A.Y., andSnyder, E.I. 1967. Catalpa glycosides. IV. The sterochemistry of catalposide.J. Org. Chem. 32:1459–1461.
Bowers, M.D. 1981. Unpalatability as a defense strategy of western checkerspot butterflies (Euphydryas Scudder, Nymphalidae).Evolution 35:367–375.
Cavill, G.W.K. 1969. Insect terpenoids and nepetalactone, pp. 203–238,in W.I. Taylor, and A.R. Battersby (eds.). Cyclopentanoid Terpene Derivatives. Marcel Dekker, Inc., New York.
Clinch, P.G., Palmer-Jones, T., andForster, I.W. 1972. Effect on honeybees of nectar from yellow Kowhai (Sophora microphylla Ait.).N.Z.J. Agric. Res. 15:194–201.
Deinzer, M.L., Thomson, P.A., Burgett, D.M., andIsaacson, D.L. 1977. Pyrrolizidine alkaloids: Their occurrence in honey from tansy ragwort (Senecio jacobaea L.).Science 195:497–499.
Elias, T.S., andGelband, H. 1975. Nectar: Its production and functions in trumpet creeper.Science 189:289–291.
Elias, T.S., Rozich, W.R., andNewcombe, L. 1975. The foliar and floral nectaries ofTurnera ulmifolia L.Am. J. Bot. 62:570–576.
Faegri, K., andVan Der Pijl, L. 1979. The Principles of Pollination Ecology, 3rd revised ed. Pergamon Press, New York.
Feinsinger, P., andSwarm, L.A. 1978. How common are ant-repellent nectars?Biotropica 10:238–239.
Guerrant, E.O., Jr., andFiedler, P.L. 1981. Flower defenses against nectar-pilferage by ants.Biotropica 13(Suppl.):25–33.
Harborne, J.B. 1977. Introduction to Ecological Biochemistry. Academic Press, New York.
Hegnauer, R. 1966. Aucubin-like glucosides: Distribution and significance as a systematic criterion.Pharm. Acta Helv. 11:577–587.
Hegnauer, R. 1973. Chemotaxonomie der Pflanzen, Vol. 6. Berkhauser Verlag, Basel.
Heineich, B. 1975. Energetics of pollination.Annu. Rev. Ecol. Syst. 6:139–170.
Heinrich, B., andRaven, P.H. 1972. Energetics and pollination ecology.Science 176:597–602.
Inouye, D.W. 1980. The terminology of floral larceny.Ecology 61:1251–1253.
Janzen, D.H. 1977. Why ants don's visit flowers.Biotropica 9:252.
Keeler, K.H. 1977. The extrafloral nectaries ofIpomoea carnea (Convolvulaceae).Am. J. Bot. 64:1182–1188.
Kerner Von Marilaun, A. 1978. Flowers and Their Unbidden Guests. Kega Paul, London.
Kooiman, P. 1970. The occurrence of iridoid glycosides in the Scrophulariaceae.Acta Bot. Neerl. 19:329–340.
Lunn, W.H., Edward, D.W., andEdward, J.T. 1962. Studies on the structure of catalposide.Can. J. Chem. 40:104–110.
Merck Index. 1976. 9th ed. Merck, Rahway, New Jersey.
Nayar, J.K., andFraenkel, C. 1963. The chemical basis of the host selection in the catalpa sphinx,Ceratomia catalpae (Lepidoptera, Sphingidae).Am. Entomol. Soc. Am. 56:119–122.
Pryce-Jones, J. 1944, Some problems associated with nectar, pollen and honey.Proc. Linn. Soc. London 1944:129–174.
Real, L.A. 1981. Uncertainty and pollinator-plant interactions: The foraging behavior of bees and wasps on artificial flowers.Ecology 62:20–26.
Rhoades, D.F., andBergdahl, F.C. 1981. Adaptive significance of toxic nectar.Am. Nat. 117:798–803.
Roth, L.M., andEisner, T. 1962. Chemical defenses of arthropods.Annu. Rev. Entomol. 7:107–136.
Stephenson, A.G. 1979. An evolutionary examination of the floral display ofCatalpa speciosa (Bignoniaceae).Evolution 33:1200–1209.
Stephenson, A.G. 1981. Toxic nectar deters nectar thieves ofCatalpa speciosa.Am. Midl. Nat. 105:381–383.
Stephenson, A.G. 1982. The role of the extrafloral nectaries ofCatalpa speciosa in limiting herbivory and increasing fruit production.Ecology.
Stephenson, A.G., andThomas, W.W. 1977. Diurnal and nocturnal pollination ofCatalpa speciosa (Bignoniaceae).Syst. Bot. 2:191–198.
Thomas, R. 1961. A possible biosynthetic relationship between the cyclopentanoid monoterpenes and the indole alkaloids.Tetrahedron Lett. 16:544–553.
Vansell, G.H. 1939. The sugar concentration of western nectars.J. Econ. Entomol. 35:321–323.
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Stephenson, A.G. Iridoid glycosides in the nectar ofCatalpa speciosa are unpalatable to nectar thieves. J Chem Ecol 8, 1025–1034 (1982). https://doi.org/10.1007/BF00987883
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DOI: https://doi.org/10.1007/BF00987883