Biodiversity and Biocontrol
One important 'service' that biodiversity may provide to society is pest control. It has long been thought that the biological diversity of natural enemies (predators, parasites and pathogens) that attack insect pests can influence the frequency and severity of pest outbreaks in both natural and agricultural ecosystems. But this hypothesis has not been rigorously tested.
Recent invasion of the soybean aphid (Aphis glycines) into the Midwestern U.S. has provided a great opportunity to examine the role of natural enemy diversity in pest control. The soybean aphid has been a spectacularly successful invader. Not only has this pest caused major economic losses for soybean farmers, it has led to increased abundance of the muti-colored Asian lady beetle (Harmonia axyridis) - an predator with a reputation for biting people and forming large swarms inside houses. The aphid has even shut down major civic events. For example, during a baseball game between the Blue Jays and Orioles in Toronto in 2001, the home plate umpire ordered the game to be stopped so that the SkyDome could be closed and the ventilation reversed to expel a cloud of migrating aphids that prevented batters from seeing the ball!
While soybean aphids have recently gone nuts, many similar types of aphids that live in the same general environment have been readily kept in check by their natural enemies. For example, pea aphids that feed on alfalfa have the same potential for explosive population growth as soybean aphids, but rarely become abundant enough to cause crop damage in the midwestern U.S. where this research is being performed. Is this because pea aphids are subject to mortality by a wider variety of natural enemies than soybean aphids? In collaboration with colleagues from the University of Wisconsin, I am using a combination of theoretical and experimental approaches to 'switch' the natural enemies of soybean and pea aphids to better understand if, and how, enemy diversity impacts the population dynamics of invasive pest species.
| Related Publications | |
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| Bruno, J., and B. J. Cardinale. 2008. Cascading effects of predator diversity. Frontiers in Ecology & the Environment 10:539-546 |
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| Duffy, J. E., B. J. Cardinale, K. E. France, M. Loreau, P. B. McIntyre, and E. Thebault. 2007. The functional role of biodiversity in food webs: Incorporating trophic complexity. Ecology Letters 10:522-538. |
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| Cardinale, B. J., J. J. Weis, K. J. Tilmon, A. E. Forbes, A. R. Ives. 2006. Biodiversity as both a cause and consequence of resource availability: A study of reciprocal causality in a predator-prey system. Journal of Animal Ecology 75:497-505. |
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| Cardinale, B.J., D. S. Srivastava, J. E. Duffy, J. P. Wright, A. L. Downing, M. Sankaran, and C. Jousseau. 2006. Effects of biodiversity on the functioning of trophic groups and ecosystems. Nature 443:989-992. |
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| Langley, S.A., K. J. Tilmon, B. J. Cardinale, and A. R. Ives. 2006. Learning, color preference, and field parasitism rates on pea aphids by the parasitoid Aphidius ervi Haliday (Hymenoptera: Braconidae). Oecologia 150:172-179. |
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| Aquilino, K., B. J. Cardinale, and A. R. Ives. 2005. Reciprocal effects of host-plant and natural enemy diversity on herbivore suppression: An empirical study of a model tri-trophic system. Oikos 108:275-282. |
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| Ives, A. R., B. J. Cardinale, and W. E. Snyder. 2005. A synthesis of sub-disciplines: predator-prey interactions, and biodiversity and ecosystem functioning. Ecology Letters 8:102-116. |
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| Cardinale, B. J., C.T. Harvey, K. Gross, and A.R. Ives. 2003. Biodiversity and biocontrol: Emergent impacts of a multi-enemy assemblage on pest suppression and crop yield in an agroecosystem. Ecology Letters 6:857-865. |
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Collaborators
- Anthony Ives, Department of Zoology, University of Wisconsin-Madison
Acknowledgements
This work was funded by grant DEB-0108300 awarded to Anthony Ives by the
National Science Foundation