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Impact of the rosette crown weevil Trichosirocalus briesei on the growth and reproduction of Onopordum thistles
Article first published online: 5 AUG 2002
DOI: 10.1046/j.1365-2664.2002.00747.x
1365-2664/asset/cover.gif?v=1&s=4510998017eb804e0bc24f63389b75ebb87101b7 "Journal of Applied Ecology")
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How to Cite
Briese, D. T., Thomann, T. and Vitou, J. (2002), Impact of the rosette crown weevil Trichosirocalus briesei on the growth and reproduction of Onopordum thistles. Journal of Applied Ecology, 39: 688–698. doi: 10.1046/j.1365-2664.2002.00747.x
Publication History
- Issue published online: 5 AUG 2002
- Article first published online: 5 AUG 2002
- Received 9 August 2001; final copy received 10 May 2002
- Abstract
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Keywords:
- Australia;
- biological control;
- herbivory;
- plant–herbivore interaction;
- weed
Summary
- 1Several European thistle species of the genus Onopordum have become naturalized in Australia and are considered serious pasture weeds, leading to a project aimed at their biological control.
- 2The population structure of a potential control agent, the crown weevil Trichosirocalus briesei, a newly described member of the Trichosirocalus horridus species group, was studied under natural conditions on its Onopordum spp. host-plants in northern Spain.
- 3Trichosirocalus briesei was found to be the most abundant of three species of crown-feeding insect utilizing these plants. Adults of this univoltine weevil began to lay eggs in mid-autumn and larval population sizes increased over winter until pupation in early spring.
- 4The spatial distribution of the immobile larvae was not random, indicating that females were selective in their oviposition behaviour. Field data suggested that plants in dense patches were attacked less frequently, and larger rosettes were preferred for egg-laying.
- 5A preliminary cage experiment indicated that feeding by T. briesei could damage Onopordum spp. thistles. A second experiment using plants in individual cages showed a clear relationship between the density of the weevils and the reduction in several growth parameters and seed production. At the highest densities, larval feeding could kill Onopordum rosettes before they produced flowering stems.
- 6These results indicated that T. briesei has the potential to contribute to the biological control of Onopordum spp. thistles in Australia. Following host-specificity testing, the weevil was released in 1997.