Oecologia (2002) 133, 193-199

Stephanie Kluth, Andreas Kruess and Teja Tscharntke (2002)
Insects as vectors of plant pathogens: mutualistic and antagonistic interactions
Oecologia 133 (2), 193-199
Abstract: Interactions between plants and their herbivores and pathogens are mostly analysed separately, thereby neglecting mutualistic or antagonistic interactions between these antagonists and possible joint effects on the host. We studied interactions between the weed Cirsium arvense, the rust fungus Puccinia punctiformis and three herbivorous insects, the aphids Aphis fabae ssp. cirsiiacanthoidis and Uroleucon cirsii, and the beetle Cassida rubiginosa. All three insect species mechanically transported spore material and significantly increased rates of P. punctiformis infection in healthy thistles. The interaction between C. rubiginosa and the fungus was antagonistic. Although C. rubiginosa transferred spores, biomass of adults was significantly reduced, development of adults tended to be prolonged and mortality increased when feeding on plants infected with P. punctiformis. In contrast, the relationship between the aphid U. cirsii and P. punctiformis was mutualistic: U. cirsii profited by fungal infection and formed significantly larger colonies on fungus-infected plants. Although the differences in insect performance suggest that aphids may be better vectors than the beetle, infection rates were similar. This is the first study to demonstrate that the relationship between herbivores, which increase the dispersal of a pathogen, and the pathogen itself can be mutualistic or antagonistic, depending on the species.
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Link to article at publishers website
Database assignments for author(s): Teja Tscharntke, Andreas Kruess

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
environment - cropping system/rotation
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
transmission/dispersal

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Cirsium arvense (weed)
Cassida rubiginosa (weed bioagent)	Cirsium arvense (weed)
Puccinia punctiformis (weed pathogen)	Cirsium arvense (weed)
Uroleucon cirsii (weed bioagent)	Cirsium arvense (weed)