DFG Research Unit FOR 2685 | C1
The detection of antiherbivore secondary compounds in the fossil record and their potential role in defense against insects
Abstract
This project aims to use solid phase microextraction gas chromatography (SPME GC-MS) and time of flight secondary ion mass spectrometry (ToF-SIMS) to analyze well-preserved fossil plants to identify any preserved traces of chemical defenses, and to understand the evolution and development of chemical defenses. We are focusing on three exceptionally preserved floras. The analyses of these fossils will be compared to analyses of fresh and decayed modern analogues and pure alkaloids known to be involved in modern chemical defenses.
This project answer two questions:
1. What chemicals were involved in the defense systems through time?
2. Is the morphology of the chemical defense structures decoupled from the actual chemicals they contain?
Plant–herbivore interactions are a product of hundreds of millions of years of antagonisms and mutualisms. Such interactions include some of the most important and complex interorganismic relationships in modern ecosystems, and plant–herbivore interactions in particular were a major component of ecosystems during the deep past: Fossil evidence indicates that plants and insects were involved in major interactions soon after macroscopic ecosystems originated on land, and herbivory ‒ the consumption of living plant tissues ‒ represents an ancient feeding strategy that extends to the Early Devonian about 410 Ma ago [1]. Almost the entire fossil history of this interaction involves arthropod damage done to plants. However, evidence for interactions in the opposite direction, specifically the prevention of plant hosts from herbivory by defense mecha-nisms, is sparse. In particular, there is almost no direct evidence of plant chemical defenses against insect herbivores (Fig. 1).
Figure 1 | Comparing our understanding of chemical interactions between insects and plants in the modern day and throughout geologic time. Diagram from embor.embopress.org.
- Extensive investigations into the trace fossil record of insect herbivory and plant physical defenses throughout geologic time (PI Wappler and collaborator Labandeira) (Fig.2) [3–6].
- Investigations into the preservation of secondary plant chemical compounds in amber, the only commonly fossilized plant chemical defense secretion (named postdoc McCoy) (Fig.3) [7].
Figure 2 | Marginal leaf feeding by a modern caterpillar (A), and in the fossil record (B). From Slater [2].
Figure 3 | SPME GC-MS investigation of volatile and semi-volatile components in Dominican amber. Some are original compounds, other were produced through amberization.
- Investigate the patterns and rates of decay and degradation of secondary plant chemicals.
- Analyze exceptionally preserved fossil plants to determine their original chemical defense systems.
- Answer questions regarding the evolutionary and ecological biology of plant–insect inter-actions through geologic time.
Prinzipal Investigator(s)
Prof. Dr. Jes Rust
Institut für Geowissenschaften / Paläontologie, Universität Bonn
Nussallee 8, 53115 Bonn
Phone: +49 228 73-48 42
E-mail: rust [at] uni-bonn.de
PD Dr. Torsten Wappler
Institut für Geowissenschaften / Paläontologie, Universität Bonn
Hessisches Landesmuseum Darmstadt
Friedensplatz 1, 64283 Darmstadt
Phone: +49 6151 1657-061
E-mail: torsten-wappler [at] hlmd.de
Researcher(s)
PhD Victoria McCoy
Institut für Geowissenschaften / Paläontologie, Universität Bonn
Nussallee 8, 53115 Bonn
Phone: +49 228 73-46 82
E-mail: vmccoy [at] uni-bonn.de
(Klick to entlarge)
EXTERNAL COLLABORATION:
This project is being carried out in collaboration with Arnoud Boom at the University of Leicester in the UK, who has expertise in the use of SPME-GC-MS and with Conrad Labandeira at the Smithsonian Museum of Natural History in the USA, who has expertise in fossil plant-insect interactions, particularly insect damage on fossil leaves.
- Labandeira CC, Tremblay SL, Bartowski KE, and Hernick LV. 2014. Middle Devonian liverwort herbivory and antiherbivore defence. New Phytologist 202:247–258.
- Slater BJ. 2014. Fossil Focus: Arthropod–plant interactions. Palaeontology Online 4(5):1–17.
- Wappler T, Currano ED, Wilf P, Rust J, and Labandeira CC. 2009. No post-Cretaceous ecosystem depression in European forests? Rich insect-feeding damage on diverse middle Palaeocene plants, Menat, France. Proc. Royal Soc. B: Biol. Sci 276:4271–4277.
- Wappler T, Labandeira CC, Rust J, Frankenhäuser H, and Wilde V. 2012. Testing for the effects and consequences of Mid Paleogene climate change on insect herbivory. PLoS ONE 7:e40744.
- Wappler T, Kustatscher E, and Dellantonio E. 2015. Plant–insect interactions from Middle Triassic (late Ladinian) of Monte Agnello (Dolomites, N-Italy)–initial pattern and response to abiotic environmental perturbations. PeerJ 3:e921. 6.Labandeira CC. 2013. Deep-time patterns of tissue consumption by terrestrial arthropod herbivores. Naturwissenschaften 100:355-364. 7.McCoy VE, Soriano C, and Gabbott SG. in press. Resin chemistry and fossilization in amber. Earth and Environmental Science Transactions of the Royal Society of Edinburgh.Referencesprobe microscopy of Pb-enriched dislocation loops. Sci. Adv. 2:e161318.
- Pe-Piper G, Zhang Y, Piper DJW & Prelević D. 2014. Relationship of Mediterranean type lamproites to large shoshonite volcanoes, Miocene of Lesbos, NE Aegean Sea. Lithos 184-187:281-299.
