Chinese Journal of Entomology (1997) 17, 100-118
Chain-Ing T. Shih and Chain-Ji Wang (1997)
Spatial dynamics of acarine predator-prey system: responses of Amblyseius ovalis (Evans) to its egg-laying behavior and density and aggregation of Tetranychus urticae Koch (Acarina: Phytoseiidae: Tetranychidae)
Chinese Journal of Entomology 17 (2), 100-118
Abstract: Stage specific spatial distribution pattern of Amblyseius ovalis on carambola fruit orchards was evaluated by the index of dispersion (ID), Green's coefficient of dispersion (Cx), Lloyd's mean crowding index (mc) and patchiness index (mc/m), Taylor's power law (log a and b), and Iwao's patchiness regression (alpha, ß) from 250 sets of sampling-date data during 1990-1995. All stage-specific populations of A. ovalis distributed intensively in random to uniform pattern; however, eggs, females, and overall stages were contagious. The degree of contagiousness of the eggs and the females was the highest among all stage-specific populations according to the results of Taylor's power law analyses of log a and b. Density-independence of contagiousness of A. ovalis was found from their low correlation coefficients between the calculated indices and prey Tetranychus urticae or predator densities, but the eggs exhibited a high relationship to its prey density. From the estimated alpha and ß values, we found the basic component units (patches) of the eggs were formed by single egg, but two or more females aggregated in the patch. The female exhibited single-egg-laying behavior within the contagiously-distributed prey cohort which resulted in the egg-aggregation among the prey patch. However, the egg and larval aggregates were due to the prey-aggregation among the patches. The species character, a high degree of uniform distribution and repulsive mechanism of egg and larva, was interpreted as the results of female egg-laying behavior in the prey cohort.
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Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Tetranychus urticae | Carambola and relatives (Averrhoa) | Taiwan | ||
| Euseius ovalis (predator) | Tetranychus urticae | Carambola and relatives (Averrhoa) | Taiwan |
