#Animals #2008 – 2011

ChemoDiversity (Contributing project)

Functional ecology: Impact of different land use intensity on chemical odour diversity, structural complexity of the vegetation and host-parasitoid interactions

Insects have a central role in the functioning and stability of ecosystems. They have important functions in nutrient cycling, food chains or pollination processes and are thus of big economical importance both as pest and as beneficial organisms. Host location is a central part in the life cycle of an insect. Herbivore and carnivore insects orientate towards food plants, prey or hosts mainly by using olfactory or visual stimuli. How does a landscape change caused by agricultural activity affect the orientation of insects and thus the interactions between them?

Hypotheses

Increasing land use intensity reduces, along with plant species diversity, the odour diversity and the structural complexity of the vegetation.
Increasing odour diversity and structural complexity functionally influence herbivore-parasitoid interactions by reducing the host finding success of the parasitoids.
Fertilization alters, besides plant species reduction, qualitatively and/or quantitatively the odour bouquet and the structure of the vegetation and thus the herbivore-parasitoid interaction.

Goals

In this project we investigate the landuse effect on vegetation complexity and on the the interactions between herbivore and carnivore insects. An increasing landuse decreases plant species diversity which in turn might change the structural complexity of the vegetation.

Moreover, a reduced number of plant species should affect the odour complexity of the vegetation, since specific compounds of plants that are not present are missing in the vegetation odour bouquet.

We are investigating the effect of the vegetation (odour diversity, structural complexity) on the orientation of insects from different trophic levels and their interactions in a landuse gradient in the system plantain (Plantago lanceolata; host plant) – Mecinus pascuorum and Mecinus labilis (weevils; herbivores) – Mesopolobus incultus (parasitic wasp).

Methods

On 80 grassland plots the vegetation structure and the abundance of insects were determined. On the same plots the odour of the vegetation is collected by headspace-sampling and will be analysed by coupled gaschromatography – massspectrometry (GC-MS) in the laboratory. In April 2009 the grassland plots were fertilised on a 6 * 6 m² area. These subplots and respective control areas are currently investigated for the direct influence of fertilisation.

Picture: The collage contains seven photos and a drawing arranged in a circle. In the centre of the circle is the writing "Chemo-Diversity" and below it the logos of the University of Würzburg and the Free University of Berlin. Photo 1 shows a beetle on a leaf stem. Photo 2 shows an unmown meadow in summer. A check-shaped warning sign is mounted in the photo, showing the black outline of a snake on a yellow background. Photo 2 shows two young scientists in a meadow reading a meter. Photo 3 shows a hand holding a pipette over a laboratory instrument. Photo 4 shows a summer meadow landscape with forests on the horizon under a blue sky with clouds. Photo 5 shows a bee or wasp. Photo 6 shows a young kneeling scientist in an unmown meadow, handling something lying in the grass in front of her. The drawing shows a kind of biosphere with soil, plants and sky, visually represented like an aquarium.

Publications

Direct and indirect effects of agricultural intensification on a host-parasitoid system on the ribwort plantain (/Plantago lanceolata/ L.) in a landscape context

Herbst C., Arnold-Schwandner S., Meiners T., Peters M. K., Rothenwöhrer C., Steckel J., Wäschke N., Westphal C., Obermaier E. (2017): Direct and indirect effects of agricultural intensification on a host-parasitoid system on the ribwort plantain (/Plantago lanceolata/ L.) in a landscape context. Landscape Ecology 32 (10), 2015–2028. doi: 10.1007/s10980-017-0562-3

Does vegetation complexity affect host plant chemistry, and thus multitrophic interactions, in a human-altered landscape?

Beeinflusst die umgebende Vegetation die Pflanzenchemie und damit pflanzenfressende Insekten und deren natürliche Feinde?

Wäschke N., Hancock C., Hilker M., Obermaier E., Meiners T. (2015): Does vegetation complexity affect host plant chemistry, and thus multitrophic interactions, in a human-altered landscape? Oecologia 179 (1), 281-292. doi: 10.1007/s00442-015-3347-x

Habitats as complex odorous environment: How does plant diversity affect herbivore and parasitoid orientation?

Lebensräume als komplexe Duftumgebungen: Wie beeinflusst die Pflanzenvielfalt die Orientierung pflanzenfressender Insekten und ihrer parasitischen Gegenspieler?

Wäschke N., Hardge K., Hancock C., Hilker M., Obermaier E., Meiners T. (2014): Habitats as complex odorous environment: How does plant diversity affect herbivore and parasitoid orientation? PLoS ONE 9(1): e85152. doi: 10.1371/journal.pone.0085152

Multitrophic interactions along a land use gradient: Effects of plant diversity and vegetation odour diversity

Wäschke N. (2013): Multitrophic interactions along a land use gradient: Effects of plant diversity and vegetation odour diversity. Dissertation, FU Berlin

Land use intensification in grasslands: higher trophic levels are more negatively affected than lower trophic levels

Intensivierung der Landnutzung auf Grünflächen beeinflusst Insekten negativer als Pflanzen

Herbst C., Wäschke N., Halboth I., Reschke S., Barto K. E., Arnold S., Geuß D., Sänger J., Meiners T., Obermaier E. (2013): Land use intensification in grasslands: higher trophic levels are more negatively affected than lower trophic levels. Entomologia Experimentalis et Applicata 147 (3), 269–281. doi: 10.1111/eea.12072

Fertilizer application decreases insect abundance on Plantago lanceolata: a large-scale experiment in three geographic regions

Düngung reduziert die Anzahl der auf dem Spitzwegerich (Plantago lanceolata L.) lebenden Insekten – ein großräumiges Experiment in drei geografischen Regionen

Hancock C., Wäschke N., Schumacher U., Linsenmair K. E., Meiners T., Obermaier E. (2013): Fertilizer application decreases insect abundance on Plantago lanceolata: a large-scale experiment in three geographic regions. Arthropod Plant Interactions 7 (2), 147-158. doi: 10.1007/s11829-012-9237-9

Influence of land use on Plantago lanceolata L. and its higher trophic levels at different spatial scales and in three geographic regions

Hancock C. (2012): Influence of land use on Plantago lanceolata L. and its higher trophic levels at different spatial scales and in three geographic regions. Dissertation, University Wuerzburg

Einfluss der Landnutzung und der umgebenden Landschaftsstruktur auf das tritrophische System des Spitzwegerichs (Plantago lanceolata)

Arnold S. (2011): Einfluss der Landnutzung und der umgebenden Landschaftsstruktur auf das tritrophische System des Spitzwegerichs (Plantago lanceolata). Thesis, University Würzburg

Influence of mowing and grazing on a tritrophic system (Plantago lanceolata, Cecidomyiidae, Chalcidoidea)

Walter M.(2010): Influence of mowing and grazing on a tritrophic system (Plantago lanceolata, Cecidomyiidae, Chalcidoidea). Bachelor thesis, University Würzburg

Einfluss von Düngung auf verschiedene Vegetationsparameter und auf die Verbreitung der Gallmückenarten Jaapiella schmidti (Rübsamen, 1902) und Lestodiplosis sp. und den Parasitoiden Aprostocetus sp. auf Plantago lanceolata

Braukmann A.(2010): Einfluss von Düngung auf verschiedene Vegetationsparameter und auf die Verbreitung der Gallmückenarten Jaapiella schmidti (Rübsamen, 1902) und Lestodiplosis sp. und den Parasitoiden Aprostocetus sp. auf Plantago lanceolata. Bachelor thesis, University Würzburg

Vegetation complexity – The influence of plant species diversity and plant structures on plant chemical complexity and arthropods

Randlkofer B., Obermaier E, Hilker M., Meiners T. (2010): Vegetation complexity—The influence of plant species diversity and plant structures on plant chemical complexity and arthropods. Basic and Applied Ecology 11, 383-395. doi:10.1016/j.baae.2010.03.003

Einfluss von Landnutzung und Vegetationsparametern auf das tritrophische System des Spitzwegerichs (Plantago lanceolata) mit besonderer Berücksichtigung des Parasitoiden Mesopolobus incultus (Hymenoptera)

Sänger J.(2010): Einfluss von Landnutzung und Vegetationsparametern auf das tritrophische System des Spitzwegerichs (Plantago lanceolata) mit besonderer Berücksichtigung des Parasitoiden Mesopolobus incultus (Hymenoptera). Thesis, University Wuerzburg

Einfluss von Stickstoffdüngung auf die Herbivorie an Plantago lanceolata

Geuß D. (2009): Einfluss von Stickstoffdüngung auf die Herbivorie an Plantago lanceolata. Bachelor thesis. Freie University Berlin

Olfaktorische Orientierung der Rüsselkäferart Mecinus pascuorum in komplexen Duftumgebungen

Hardge K.(2009): Olfaktorische Orientierung der Rüsselkäferart Mecinus pascuorum in komplexen Duftumgebungen. Bachelor thesis Freie University Berlin

Der Einfluss unterschiedlicher Landnutzungsintensität auf die Herbivorendichte und – diversität von Plantago lanceolata und die strukturelle Komplexität der Vegetation

Halboth I. (2009): Der Einfluss unterschiedlicher Landnutzungsintensität auf die Herbivorendichte und – diversität von Plantago lanceolata und die strukturelle Komplexität der Vegetation. Thesis, University Wuerzburg

Untersuchungen an und um Plantago lanceolata L. auf landwirtschaftlich genutzten Flächen in der Schorfheide: Wie wirken sich Wirtspflanzenparameter und Vegetationskomplexität auf eine Herbivoren-Parasitoid-Interaktion aus?

Reschke S. P. (2009): Untersuchungen an und um Plantago lanceolata L. auf landwirtschaftlich genutzten Flächen in der Schorfheide: Wie wirken sich Wirtspflanzenparameter und Vegetationskomplexität auf eine Herbivoren-Parasitoid-Interaktion aus? Thesis, Freie University Berlin

Scientific assistants

Alumni

Dr. Torsten Meiners

Alumni

PD Dr. Elisabeth Obermaier