Evolution of the Suctorial Proboscis in Pollen Wasps (Masarinae, Vespidae)
Arthropod Structure & Development 31 (2002) 103–120 www.elsevier.com/locate/asd Evolution of the suctorial proboscis in pollen wasps (Masarinae, Vespidae) Harald W. Krenna,*, Volker Maussb, John Planta aInstitut fu¨r Zoologie, Universita¨t Wien, Althanstraße 14, A-1090, Vienna, Austria bStaatliches Museum fu¨r Naturkunde, Abt. Entomologie, Rosenstein 1, D-70191 Stuttgart, Germany Received 7 May 2002; accepted 17 July 2002 Abstract The morphology and functional anatomy of the mouthparts of pollen wasps (Masarinae, Hymenoptera) are examined by dissection, light microscopy and scanning electron microscopy, supplemented by field observations of flower visiting behavior. This paper focuses on the evolution of the long suctorial proboscis in pollen wasps, which is formed by the glossa, in context with nectar feeding from narrow and deep corolla of flowers. Morphological innovations are described for flower visiting insects, in particular for Masarinae, that are crucial for the production of a long proboscis such as the formation of a closed, air-tight food tube, specializations in the apical intake region, modification of the basal articulation of the glossa, and novel means of retraction, extension and storage of the elongated parts. A cladistic analysis provides a framework to reconstruct the general pathways of proboscis evolution in pollen wasps. The elongation of the proboscis in context with nectar and pollen feeding is discussed for aculeate Hymenoptera. q 2002 Elsevier Science Ltd. All rights reserved. Keywords: Mouthparts; Flower visiting; Functional anatomy; Morphological innovation; Evolution; Cladistics; Hymenoptera 1. Introduction Some have very long proboscides; however, in contrast to bees, the proboscis is formed only by the glossa and, in Evolution of elongate suctorial mouthparts have some species, it is looped back into the prementum when in occurred separately in several lineages of Hymenoptera in repose (Bradley, 1922; Schremmer, 1961; Richards, 1962; association with uptake of floral nectar.
[Show full text]