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Variation in predator foraging behaviour changes predator–prey spatio-temporal dynamics

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1. Foraging underlies the ability of all animals to acquire essential resources and thus provides a critical link to understand population dynamics. A key issue is how variation in foraging behaviour affects foraging efficiency and predator–prey interactions in spatially heterogeneous environments. However, there is very little quantitative information available on this topic. 2. We evaluated the impact of variation in predator foraging on population dynamics of the predatory mite, Phytoseiulus persimilis, and its prey, the twospotted spider mite, Tetranychus urticae, in a heterogeneous environment. 3. Through artificial selection, we generated predator lines with high levels of prey consumption, conversion efficiency or dispersal, which were otherwise similar in foraging and life history. With these lines, we experimentally compared the effect of these traits on temporal and spatial patterns of predators and prey. 4. We initiated the experiments in a 24-plant landscape, which contained two discrete prey patches (i.e. prey-infested plants) under two initial predator–prey population ratios (1 : 10 and 1 : 30). Predators were introduced into one of the prey patches and were left to forage for 24 days. 5. Predator population growth was similar among the three selected lines, but the high conversion efficiency line produced the most predators and had the highest predator–prey ratio, and the high consumption and high dispersal lines were intermediate. The unselected line showed the least predator growth and lowest predator–prey ratio throughout the experiment. 6. Initial predator–prey ratio did not affect the impact of the selected lines on prey population growth at the high (1 : 10) ratio. However, at the low predator–prey ratio (1 : 30), the unselected line had a much greater prey numbers than the selected lines. 7. Predators and prey were each individually aggregated, but the high conversion efficiency and high dispersal lines showed stronger spatial association and correlation with prey, while the high consumption line was less closely associated or correlated with the prey. 8. These results indicate that there may be multiple, equally effective strategies by which predators exploit prey in patchy landscapes, but suggest that the long-term dynamics may not be stable under all of these strategies.
Nachappa, Punya , Margolies, David C. , Nechols, James R. , Campbell, James F.
Includes references
Functional ecology 2011 Dec., v. 25, no. 6
Blackwell Scientific Publications
Journal Articles, USDA Authors, Peer-Reviewed
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