Floral scent and deceptive pollination in Aristolochia

Interactions between plants and other organisms represent one of the most fascinating topics in ecology and evolutionary biology, among which pollination of angiosperms by animals consistently evokes particular scientific interest. During the last decades many studies considerably contributed to our mechanistic understanding of the diversity in plant-pollinator interactions. However, our knowledge about the specific nature of many pollination systems, especially those between deceptive plants and their dipteran pollinators, is still limited due to: a) the dipteran species richness, b) their challenging identification and taxonomy, c) the rudimentarily knowledge about the ecology of most fly species, and d) the virtually unlimited number of potential resources / models that could be imitated. West Mediterranean Aristolochia species are known to be pollinated by flies. However, this is only true for the family- or genus- but mostly not for the species-level with the resource imitated / mimicked unknown for most of the species. These gaps of knowledge will be closed by applying a comparative and multidisciplinary approach aiming at the identification of pollinator taxa, the mechanisms of pollinator attraction, and the deceptive strategies of several Aristolochia species. The nature and specificity of floral scents is of particular interest. We hypothesize that a) floral scents and pollinators (species, sexes) differ among closely related Aristolochia species, b) plants attract pollinators from the potentially available pollinator fauna with high specificity (species, sex), and c) different Aristolochia species evolved different pollination strategies and exploit different behaviors of their pollinators. The project combines integrative taxonomy with ecological and chemo-ecological methods. Pollinators will be identified morphologically and by applying latest molecular high-throughput methods. Flower scent composition will be determined by chemical-analytical methods, while chemical-electroantennographic approaches will serve to identify biologically active compounds. Bioassays with fly pollinators will reveal the attractiveness of floral scent mixtures and individual compounds thereof. Chemical-analytical and -electrophysiological analyses with (potential) models imitated, together with bioassays, will elucidate the deceptive strategy of the plants. Hence this project will provide novel insights into the pollination ecology and diversity in deceptive pollination systems, like the new one between food steeling Chloropidae and Aristolochia rotundathat we recently discovered (kleptomyiophily). Additionally, the study will contribute to a better general understanding of interactions between deceptive angiosperm flowers and pollinators. We expect that our results will foster even more research in this and adjacent fields. Our results will also be of considerable interest for the public, as our previous studies in A. rotunda were.

PhD student: MSc Thomas Rupp

In collaboration with  Professor Prof. Dr. Stefan Wanke, Dr. Birgit Oelschlägel, Prof. Dr. Christoph Neinhuis

Oelschlägel, B; von Tschirnhaus, M; Nuss, M; Nikolić, T; Wanke, S; Dötterl, S; Neinhuis, C: Spatio-temporal patterns in pollination of deceptive Aristolochia rotunda L. (Aristolochiaceae). Plant Biology, 18, 928–937 (2016)

Oelschlägel, B; Nuss, M; von Tschirnhaus, M; Pätzold, C; Neinhuis, C; Dötterl, S; Wanke, S: The betrayed thief – the extraordinary strategy of Aristolochia rotunda to deceive its pollinators. New Phytologist, 206, 342-351 (2015)