, Volume 50, Issue 3, pp 316–319 | Cite as

Nectar parasitism of Asclepias syriaca by ants: Effect on nectar levels, pollinia insertion, pollinaria removal and pod production

  • Robert S. Fritz
  • Douglass H. Morse


Milkweed (Asclepias syriaca L.) umbels and stems attended by ants (Lasius neoniger Emery and Tapinoma sessile (Say)) initiated significantly fewer pods and showed a trend to produce fewer mature pods than did umbels and stems not attended by ants. Since similar numbers of pollinia were inserted in ant-attended flowers, we hypothesize that ant-excluded flowers obtain more pollinia from other clones than do ant-attended flowers of this normally non-selfing species. If pollinators from other clones first visited flowers not depleted of nectar by ants, they could provide this source of foreign pollinia. Our experiments suggest that nocturnal noctuid and geometrid moths can provide these pollinia.


Geometrid Moth Nectar Level Asclepias Syriaca Pollinaria Removal Tapinoma Sessile 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Bertin RI, Willson MF (1980) Effectiveness of diurnal and nocturnal pollination of two milkweeds. Can J Bot 58:1744–1746Google Scholar
  2. Brantjes NBM (1976) Riddles around the pollination of Melandrium album (Mill.) Garcke (Caryophyllaceae) during the oviposition by Hadena bicruris Hufn, (Noctuidae, Lepidoptera). I. Proceedings K. Nederlandse Akademie van Wetenschappen, Ser C 79:125–141Google Scholar
  3. Brantjes NBM (1978) Sensory responses to flowers in night-flying moths. Linn Soc Symp Ser 6:13–19Google Scholar
  4. Faegri K, van der Piil L (1979) The principles of pollination biology. Pergamon Press, TorontoGoogle Scholar
  5. Galil J, Zeroni M (1965) Nectar system of Asclepias curassavica. Bot Gaz 130:1–4Google Scholar
  6. Heinrich B, Raven PH (1972) Energetics and pollination ecology. Science 176:597–602Google Scholar
  7. Inouye DW (1981) The ecology of nectar robbing. In: TS Elias and BL Bentley (eds) The biology of nectaries. Columbia University Press, New York. (in press)Google Scholar
  8. Lynch SP (1977) The floral ecology of Asclepias solanoana Woods. Madroño 24:159–177Google Scholar
  9. Morse DH (1981) Modification of bumble bee foraging: the effect of milkweed pollinia. Ecology 62:89–97Google Scholar
  10. Morse DH: Patterns of pollinia accretion and loss on bumble bees. In preparationGoogle Scholar
  11. Proctor M, Yeo P (1973) The pollination of flowers. Taplinger Publ Co, New YorkGoogle Scholar
  12. Sparrow FK, Pearson NL (1948) Pollen compatability in Asclepias syriaca. J Agric Res 77:187–199Google Scholar
  13. Willson MF, Bertin RI (1979) Flower visitors, nectar production, and infloresence size of Asclepias syriaca. L. Can J Bot 57:1380–1388Google Scholar
  14. Willson MF, Price PW (1977) The evolution of infloresence size in Asclepias (Asclepiadaceae). Evolution 31:495–511Google Scholar
  15. Willson MF, Price PW (1980) Resource limitation of fruit and seed production in some Asclepias species. Can J Bot 58:2229–2233Google Scholar
  16. Willson MF, Rathke BJ (1974) Adaptive design of the floral display in Asclepias syriaca L. Am Midl Nat 92:47–57Google Scholar
  17. Wyatt R (1976) Pollination and fruit-set in Asclepias: a reappraisal. Am J Bot 63:845–851Google Scholar
  18. Wyatt R (1979) Experimental evidence concerning the role of the corpusculum in Asclepias pollination. Syst Bot 3:313–321Google Scholar
  19. Wyatt R (1980) The impact of nectar-robbing ants on the pollination system of Asclepias curassavica. Bull Torrey Bot Club 107:24–28Google Scholar

Copyright information

© Springer-Verlag 1981

Authors and Affiliations

  • Robert S. Fritz
    • 1
    • 2
  • Douglass H. Morse
    • 1
    • 2
  1. 1.Department of ZoologyUniversity of MarylandCollege ParkUSA
  2. 2.Division of Biology and MedicineBrown UniversityProvidenceUSA

Personalised recommendations