FWF project P 22248 B17

Extremely long mouthparts in flower-visiting insects:
form, function and evolution

Extremely long mouthparts that serve for the uptake of nectar in flower visiting insects provide ample opportunity to examine constraints on organ evolution. The majority of the flower visiting insects are regarded as short-tongued since their mouthparts are shorter than the head, while extremely long proboscides, i.e., exceeding body length, are rare. Advantages of long proboscides have been previously formulated and tested in nectar feeding from long spurred flowers. The project represents the first attempt to evaluate the costs of long mouthparts. The research will compare flower-visiting insects which have an average-sized tubular proboscis with related species having extremely long mouthparts.

The estimation of anatomical and functional costs of extremely long proboscid mouthparts should contribute significantly to our understanding of the evolution of form and function in context with insect feeding behaviour on flowers.

Hypotheses

(1) Anatomical costs are optimized in those regions of the proboscis which are disproportionately elongated to the extent that they contain fewer muscles and sensillae compared to corresponding regions in average-sized proboscides of closely related species.

(2) Anatomical costs of variously long proboscides within a single species will provide an estimate of the extra expenses which accompany advances of proboscis elongation.

(3) Biometry and biomechanics of the suction pumps correlate with the proboscis length.

(4) Flower handling time should greatly increase in butterflies and nemstrinid flies with extremely long proboscides.

The study deals with hawk moths, neotropical butterfly of the families Riodinidae and Hesperiidae, neotropical bees (Euglossini) and South Africa tangle-veined fly (Nemestrinidae).

The microanatomical studies use electronmicroscopy and micro-CT as well as biometric analyses of body size and proboscis length. Field studies take place in the Tropical Biological Station La Gamba (Costa Rica) and in South Africa.

Micro anatomical studies combine scanning electron microscopy, semithin sectioning and µCT imaging with Amira 3D reconstructions. In addition, biometric analyses of body size, proboscis length and flower handling times represent major research topics. Field studies take place in La Gamba (Costa Rica) and Hantam National Botanical Garden, Nieuwoudtville (Western Cape Province, South Africa).

Fotos

   
Eurybia lycisca on an inflorescence of Calathea crotalifera   Euglossa sp. on an inflorescence of Calathea crotalifera   Proseoca sp. on Babiana praemorsa

Video

Research team

Research topics of the phd-students

Julia Bauder is working on morphology, biometry and feeding of Hesperiidae and Riodinidae in the Tropical Research Station La Gamba (Costa Rica, Puntarenas). The butterflies were collected in the surroundings of the station and feeding experiments were performed in cages. Video analyses allow to conclude on feeding performance in species that possess either a short or a long proboscis.

Florian Karolyi is working on the ecomorphology, morphometrics and flower handling times of long-proboscid nemestrinid flies from the genus Prosoeca, in the Hantam National Botanical Garden and the Wild Flower Reserve in the surroundings of Nieuwoudtville on the Bokkeveld Plateau. Differences in the Flower handling of short- and long-proboscid individuals are investigated.

Research topics of the master students

Jellena Vanessa Düster - Micromorphology of the mouthparts of Euglossini

Cooperation partners

Jonathan Colville – South African National Biodiversity Institute (SANBI), Cape Town, South Africa

Stephan Handschuh – VetCore Facility, University of Veterinary Medicin, Vienna, Austria

Department of Theoretical Biology (University of Vienna)

Department of Cell Imaging and Ultrastructural Research (University of Vienna)

Congress activities

6th Conference on the Biology of Butterflies, Edmonton, Canada

Lieskonig NH, Krenn HW.  2010. Proboscis features of butterflies – an additional set of characters for the phylogeny of Nymphalidae (Lepidoptera). 6th International Conference on the Biology of Butterflies, University of Alberta Edmonton, program & abstracts p 49

Bauder J, Lieskonig, N. Krenn HW. 2010. The extremely long tongued Neotropical butterfly Eurybia lycisca (Riodinidae): Proboscis morphology and flower handling. 6th International Conference on the Biology of Butterflies, University of Alberta Edmonton, Canada, program & abstracts p 27

Euro Evo Devo Lisbon 2012, Portugal, July 10 -13

Florian Karolyi, Adaptations for nectar-feeding in the mouthparts and the suction pump of long-proboscid flies (Nemestrinidae: Prosoeca).

Harald W. Krenn, Evolution of mouthparts in Lepidoptera: adaptations to collect nectar and pollen.

ÖEG Kolloquium Wien 2012, March 17

Florian Karolyi: Die Saugpumpe langrüsseliger Fliegen (Diptera: Nemestrinidae) in Südafrika.

Julia Bauder: Die Mundwerkzeuge und Saugpumpe bei Riodinidae (Lepidoptera) mit unterschiedlich langen Rüsseln.

Krenn HW, Bauder J A-S, Karolyi F, Gruber MH. 2013. Extremely long mouthparts in flower-visiting insects: form, function and evolution. 106th Annual Meeting of the German Zoological Society, September 13-16th, 2013, Ludwig-Maxilians-Universität München

Publications

Bauder JAS, Lieskonig N, Krenn HW. 2011. The extremely long-tongued Neotropical butterfly Eurybia lycisca (Riodinidae): Proboscis morphology and flower handling. Arthropod Structure & Development 40: 122-127.

Bauder ASJ, Handschuh S, Metscher BD, Krenn HW. 2013. Functional morphology of the feeding apparatus and evolution of proboscis length in metalmark butterflies (Lepidoptera: Riodinidae). Biological Journal of the Linnean Society, 110(2): 291-304

Karolyi F, Szucsich NU, Colville JF, Krenn HW. 2012. Adaptations for nectar-feeding in the mouthparts of long-proboscid flies (Nemestrinidae: Prosoeca) Biological Journal of the Linnean Society, 107: 414-424.

Karolyi F, Colville JF, Handschuh S, Metscher BD and Krenn HW. 2013. Suction feeding using an extremely long proboscis in a tangle-winged fly (Nemestrinidae). Naturwissenschaften 100: 1083-1093, DOI 10.1007/s00114-013-1114-6.

Karolyi F, Colville JF, Handschuh S, Metscher BD and Krenn HW. In preparation. Functional morphology of the feeding apparatus of long-proboscid Tabanidae (Diptera: Philoliche)

Public outreach

University of Vienna - http://forschungsnewsletter.univie.ac.at/forschungsnewsletter-neu/jaennerfebruar-2014/

APA News 11.12.2013 - Fliegen mit langem Saugrüssel haben die Nase vorn

Der Standard – Mit langem Rüssel lässt es sich besser naschen, 12.03.2014

 


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