ScienceDaily (Aug. 18, 2010) — A 48-million-year-old fossilised leaf has revealed the oldest known evidence of a macabre part of nature -- parasites taking control of their hosts to turn them into zombies.
This is the 48-million-year-old fossil leaf from Messel which bears the tell-tale death grip scars. (Credit: Torsten Wappler)
The discovery has been made by a research team led by Dr David P Hughes, from the University of Exeter, who studies parasites that can take over the minds of their hosts.
All manner of animals are susceptible to the often deadly body invasion, but scientists have been trying to track down when and where such parasites evolved.
Dr Hughes, from the University's School of Biosciences, said: "There are various techniques, called a molecular clock approach, which we can use to estimate where and when they developed and fossils are an important source of information to calibrate such clocks.
"This leaf shows clear signs of one well documented form of zombie-parasite, a fungus which infects ants and then manipulates their behaviour."
The fungus, called Ophiocordyceps unilateralis, causes ants to leave their colonies and head for a leaf which provides the ideal conditions for the host to reproduce.
When it gets there the ant goes into a 'death grip'- biting down very hard on the major vein of a leaf. This means that when the ant dies, its body stays put so the fungus has time to grow and release its spores to infect other ants.
The death grip bite leaves a very distinct scar on the leaves. This prompted Dr Hughes, together with research partners Conrad Labandeira from the Smithsonian Institution in the USA and Torsten Wappler, from the Steinmann Institute in Germany, to search for potential evidence of the fungus at work by studying the fossilised remains of leaves....
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Ancient death-grip leaf scars reveal ant–fungal parasitism
David P. Hughes1,2,3,*,
Torsten Wappler4 and
Conrad C. Labandeira5,6,*
1Department of Organismic and Evolutionary Biology, Harvard University,Cambridge, MA 02138, USA
2School of Biosciences, University of Exeter, Exeter EX4 4QJ, UK
3Department of Entomology, Penn State University, University Park, PA 16802, USA
4Steinmann Institute, University of Bonn, 53113 Bonn, Germany
5Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013, USA
6Department of Entomology, University of Maryland, College Park, MD 20742, USA
*Authors for correspondence (email@example.com;firstname.lastname@example.org).
Parasites commonly manipulate host behaviour, and among the most dramatic examples are diverse fungi that cause insects to die attached to leaves. This death-grip behaviour functions to place insects in an ideal location for spore dispersal from a dead body following host death. Fossil leaves record many aspects of insect behaviour (feeding, galls, leaf mining) but to date there are no known examples of behavioural manipulation. Here, we document, to our knowledge, the first example of the stereotypical death grip from 48 Ma leaves of Messel, Germany, indicating the antiquity of this behaviour. As well as probably being the first example of behavioural manipulation in the fossil record, these data support a biogeographical parallelism between mid Eocene northern Europe and recent southeast Asia.
ant–fungal parasitism tritrophic interaction middle Eocene Messel
Received June 7, 2010.
Accepted July 26, 2010.
© 2010 The Royal Society
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