FWF-Projekt: 18425-B03

POLLEN FEEDING IN BUTTERFLIES:
EVOLUTION OF A NEW MECHANISM OF NUTRIENT EXTRACTION

The unique pollen feeding behaviour of the closely related butterflies from the genera Heliconius and Laparus (Nymphalidae) represents a key innovation for their advanced life-history. These neotropical butterflies feed on floral nectar and pollen; the latter provides a vital source of nitrogen for adult cyanogenesis, extended reproductive life and nuptial gifts. The mouthparts and the flower probing behaviour show adaptations to pollen gathering and to the extra-oral extraction of amino acids from adherent pollen grains. The extraction process involves the use of a fluid of uncertain origin and an unknown mechanism for dissolving substances from pollen. Understanding the mechanism of pollen feeding should provide insights into the novel feeding behaviour which opened a new adaptive field to butterflies and allow conclusions to be made on the evolution of the key innovations which are pivotal for the sophisticated behaviour of these insects.

The present research concerns

(1) the internal organs, i.e. salivary glands of Heliconius butterflies in comparison to related species

(2) the mechanisms of pollen processing

(3) the impact of pollen processing on the condition of pollen and the implications for pollination

(4) comparative analysis of pollen processing behavior

The research combines morphological methods (LM and EM-techniques), chemical analysis and experimental work in the laboratory of the University of Vienna and Brackenridge Field Laboratory at the University of Texas, Austin, USA as well as field studies in the Tropical Research Station La Gamba (Costa Rica). Laboratory populations of Heliconius are reared in the laboratory of the University of Vienna

This research is funded by the Austrian Science Fund (FWF Project 18425 – B03)

Diversity of Heliconius butterflies

   
Heliconius melpomene visits flowers of Lantana camara to feed on nectar and pollen (University Vienna)   Heliconius hecale, nectar feeding in a green house of the University Vienna   Heliconius sara, on a Lantana flower in a green house of the University Vienna
   
Heliconius hecale, visits a Psychotria elata flower (Tropical Research Station La Gamba, Costa Rica)   Heliconius pachinus with a pollen load on the proboscis (Tropical Research Station La Gamba, Costa Rica)   Dried Heliconius ethilla with a pollen load

Watch Heliconius butterflies feeding

   
Heliconius erato visits one of the favorit flowers, Psiguria tabascensis (Cucurbitaceae) for nectar (in the laboratory of Lawrence Gilbert, University of Texas at Austin)   Heliconius hecale takes up pollen from an opened flower of Psiguria tabascensis (in the laboratory of Lawrence Gilbert, University of Texas at Austin)   Heliconius hecale processes the pollen load in fluid to extract amino acids

 

Summarizing poster contribution ICBB 2010, Edmonton, Canada

Mechanism of pollen processing behavior in Heliconius butterflies (pdf)

Publications

Krenn HW. 2010. Feeding Mechanisms of Adult Lepidoptera: Structure, Function, and Evolution of the Mouthparts. Annu. Rev. Entomol. 2010. 55: 307–27. pdf

Krenn HW, Eberhard MJB, Eberhard SH, Hikl AL, Huber W, Gilbert LE. 2009. Mechanical damage to pollen aids nutrient acquisition in Heliconius butterflies (Nymphalidae). Arthropod-Plant Interactions DOI 10.1007/s11829-009-9074-7. pdf

Eberhard SH, Hikl AL, Boggs CL, Krenn HW. 2009. Saliva or Regurgitated Nectar? What Heliconius Butterflies (Lepidoptera: Nymphalidae) Use for Pollen Feeding. Annals of the Entomological Society of America 102(6): 1105-1108). pdf

Eberhard SH, Nemeschkal HL, Krenn HW. 2009. Biometrical evidence for adaptations of the salivary glands to pollen feeding in Heliconius butterflies (Lepidoptera: Nymphalidae). Biological Journal of the Linnean Society 97: pp 604–612. pdf

Krenn, HW (2008) Feeding behaviours of neotropical butterflies. In Weissenhofer A., Huber W., Mayer V., Pamperl, Weber A., Aubrecht G (Eds) Natural and Cultural History of the Golfo Dulce Region, Costa Rica, Stapfia 88 zugleich Kataloge der oberösterreichischen Landesmuseen Neue Serie 80, Biologiezentrum der Oberösterreichischen Landesmuseen, pp 295-304. pdf

Eberhard SH, Hrassnigg N, Crailsheim K, Krenn HW. 2007. Evidence of protease in the saliva of the butterfly Heliconius melpomene (L.) (Nymphalidae, Lepidoptera). Journal of Insect Physiology 53: 126-131. pdf

Penz CM, Krenn HW (2000) Behavioral adaptations to pollen-feeding in Heliconius butterflies (Nymphalidae, Heliconiinae): an experiment using Lantana flowers. Journal of Insect Behavior 13: 865-880. pdf

Krenn HW, Penz CM (1998) Mouthparts of Heliconius butterflies (Lepidoptera: Nymphalidae): a search for anatomical adaptations to pollen-feeding behaviour. International Journal of Insect Morphology & Embryology 27: 301-309.

Cooperations

Lawrence E. Gilbert (School of Biological Sciences, Section of Integrative Biology, University of Texas, Austin, TX 78712, USA)

Univ.Prof. Dr. K. Crailsheim and Univ.-Ass. Dr. N. Hrassnigg (Institute of Zoology, University Graz).

Carla M. Penz (Department of Biological Sciences, University of New Orleans, New Orleans, USA).

Hans L. Nemeschkal (Department of Theoretical Biology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria)

Institution of Cell Imaging and Ultrastructure Research (University of Vienna).

La Gamba Biological Station (Tropenstation La Gamba, Golfito/Puntarenas, Postal 178, Costa Rica).

Links

Tropenstation La Gamba: www.lagamba.at

Carla Penz: http://biology.uno.edu/penzbio.aspx

Lawence Gilbert, head of Brackenridge Field Lab: www.utexas.edu/research/bfl

Univ Prof K. Crailsheim (University Graz): www.kfunigraz.ac.at/zoowww/personal/crails/crail.htm

Heliconius Homepage: www.heliconius.org

Hans Nemeschkal: http://www.univie.ac.at/theoretical/

Institution of Cell Imaging and Ultrastructure Research : www.univie.ac.at/cius



top