Research interests


  • pollination ecology and chemical ecology of European orchids
  • floral scent
  • sexual deception
  • isolation mechanisms
  • animal-plant interactions


Scientific projects

Epipactis helleborine (L.) Crantz (Orchidaceae), the Broad-leaved Helleborine occurs from North Africa to Asia and Europe. It attracts its pollinator by partial deceit. The flowers emit so-called “Green Leaf Volatiles” which normally are produced by plants infested by herbivorous insects, such as caterpillars. Thereby they attract prey-hunting predatory wasps for pollination.Up to now more than 30 subspecies of E. helleborine (L.) Crantz (Kew World Checklist of Selected Plant Families, 2015) have been described according to differing morphological traits such as size and colouration of the flowers, leaf shape and size, height of the shoot or flowering times. In most habitats, several subspecies as well as transition forms can be found in sympatry (Bergfeld & Berlinghof, 2011; Lorenz et al., 2011). In addition, it has been shown that there is high intraspecific diversity of morphological traits in the nominate form E. helleborine helleborine according to different habitats (Lorenz et al., 2011) and it is often difficult or not possible to discriminate between subspecies in the field. So far, no information exists about isolation barriers between these subspecies. Therefore it is not clear, whether the described taxa are really subspecies, if they represent ecotypes or if there is evidence for an early stage of speciation.

Molecular studies (Tranchida-Lombardo et al 2011) suggest the presence of recurrent hybridization or a very recent/ongoing reproductive divergence.

In this context my Ph.D thesis focuses on possible isolation barriers occurring between the three taxa E. helleborine subsp. helleborine, E. helleborine subsp. moratoria and E. helleborine subsp. minor.  I aim to clarify the taxonomy of E. hel. helleborine, E. hel.  minor and E. hel. moratoria and to search for premating or postmating isolation barriers. I expect the morphology of the flowers and the pollinator attracting scent to play a hypothetical role for premating isolation and I study hybrid fertility as a hypothetical postmating barrier.  



Dietel J, Bergfeld D, Berlinghof N, Riechelmann A, Ayassa M (2015) Taxonomical investigations on the deceptive orchid Epipactis helleborine (L.) Crantz (Epidenroidae, Orchidaceae). J Eur Orch 47 (1): 501-522

Conference contributions

Dietel J, Ayasse M (2014) Bestäubungsbiologie und Taxonomie der Breitblättrigen Stendelwurz Epipactis helleborine. 11th Hymenopterological Conference, Stuttgart, Germany (talk)

Dietel J, Ayasse M (2015) Speciation and pollination ecology of the orchid Epipactis helleborine. International Conference on Temperate Orchids Research & Conservation TORC’15, Samos Island, Greece (talk)


  • M. Sc. Jennifer Dietel
  • Institute of Evolutionary Ecology and Conservation Genomics
  • Ulm University
  • Albert-Einstein-Allee 11
  • D-89081 Ulm, Germany
  • Tel. +49 (0)731 50 22691
  • Fax +49 (0)731 50 22683
  • Office: M25 4113