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Functional responses and prey-stage preferences of a predatory gall midge and two predacious mites with twospotted spider mites, Tetranychus urticae, as host.

Xiao Y, Osborne LS, Chen J, McKenzie CL - J. Insect Sci. (2013)

Bottom Line: The results showed that F. acarisuga was highly effective and the two species of predacious mites were moderately effective in feeding on T. urticae eggs.A female N. californicus produced more eggs than a female A. swirskii did when they both fed on T. urticae eggs.In addition, all three predator species had no preystage preference for either prey eggs or nymphs.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology and Nematology, Mid-Florida Research and Education Center, University of Florida, Apopka, FL, USA 32703. yfxiao@ufl.edu

ABSTRACT
The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an important pest of vegetables and other economically important crops. This study evaluated the functional responses and prey-stage preferences of three species of predators, a predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae), and two predatory mite species, Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) and Amblyseius swirskii (AnthiasHenriot), with T. urticae as the host, under laboratory conditions. The results showed that F. acarisuga was highly effective and the two species of predacious mites were moderately effective in feeding on T. urticae eggs. Logistic regression analysis suggested Type II (convex) functional responses for all three species. However, based on the estimates of the handling time and the attacking rates, the three predators had different predation capacities. Among the three species, F. acarisuga had the highest predation on T. urticae. The maximum daily predation by a larval F. acarisuga was 50 eggs/day, followed by a female N. californicus (25.6 eggs/day) and a female A. swirskii (15.1 eggs/day). A female N. californicus produced more eggs than a female A. swirskii did when they both fed on T. urticae eggs. In addition, all three predator species had no preystage preference for either prey eggs or nymphs. The findings from this study could help select better biological control agents for effective control of T. urticae and other pests in vegetable productions.

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Related in: MedlinePlus

Relationship among the number of Tetranychus urticae eggs preyed by larval Feltiella acarisuga, female Amblyseius swirskii, and Neoseiulus californicus with the prey density of T. urticae (eggs) provided on bean leaf discs per day. For all three species, the data followed the Type Il convex functional response in which the number of prey consumed increased with prey density up to a maximum point, after which it began to slowly decrease. High quality figures are available online.
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f01_01: Relationship among the number of Tetranychus urticae eggs preyed by larval Feltiella acarisuga, female Amblyseius swirskii, and Neoseiulus californicus with the prey density of T. urticae (eggs) provided on bean leaf discs per day. For all three species, the data followed the Type Il convex functional response in which the number of prey consumed increased with prey density up to a maximum point, after which it began to slowly decrease. High quality figures are available online.

Mentions: For all three species, logistic regression analysis showed that linear coefficient (b) was < 0, suggesting that the proportion of prey eggs killed decreased as a function of egg density offered, which was the Type II (convex) functional response (Table 1). The curves of functional responses on T. urticae eggs by the three predator species were presented in Figure 1. Natural mortality of prey eggs observed in the control treatment (without any predator) was minimal: 1.5 ± 0.5%, 1.0 ± 0.3%, and 2.6 ± 0.5%. These results suggested that the three predator species effectively predated T. urticae eggs.


Functional responses and prey-stage preferences of a predatory gall midge and two predacious mites with twospotted spider mites, Tetranychus urticae, as host.

Xiao Y, Osborne LS, Chen J, McKenzie CL - J. Insect Sci. (2013)

Relationship among the number of Tetranychus urticae eggs preyed by larval Feltiella acarisuga, female Amblyseius swirskii, and Neoseiulus californicus with the prey density of T. urticae (eggs) provided on bean leaf discs per day. For all three species, the data followed the Type Il convex functional response in which the number of prey consumed increased with prey density up to a maximum point, after which it began to slowly decrease. High quality figures are available online.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3735104&req=5

f01_01: Relationship among the number of Tetranychus urticae eggs preyed by larval Feltiella acarisuga, female Amblyseius swirskii, and Neoseiulus californicus with the prey density of T. urticae (eggs) provided on bean leaf discs per day. For all three species, the data followed the Type Il convex functional response in which the number of prey consumed increased with prey density up to a maximum point, after which it began to slowly decrease. High quality figures are available online.
Mentions: For all three species, logistic regression analysis showed that linear coefficient (b) was < 0, suggesting that the proportion of prey eggs killed decreased as a function of egg density offered, which was the Type II (convex) functional response (Table 1). The curves of functional responses on T. urticae eggs by the three predator species were presented in Figure 1. Natural mortality of prey eggs observed in the control treatment (without any predator) was minimal: 1.5 ± 0.5%, 1.0 ± 0.3%, and 2.6 ± 0.5%. These results suggested that the three predator species effectively predated T. urticae eggs.

Bottom Line: The results showed that F. acarisuga was highly effective and the two species of predacious mites were moderately effective in feeding on T. urticae eggs.A female N. californicus produced more eggs than a female A. swirskii did when they both fed on T. urticae eggs.In addition, all three predator species had no preystage preference for either prey eggs or nymphs.

View Article: PubMed Central - PubMed

Affiliation: Department of Entomology and Nematology, Mid-Florida Research and Education Center, University of Florida, Apopka, FL, USA 32703. yfxiao@ufl.edu

ABSTRACT
The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an important pest of vegetables and other economically important crops. This study evaluated the functional responses and prey-stage preferences of three species of predators, a predatory gall midge, Feltiella acarisuga (Vallot) (Diptera: Cecidomyiidae), and two predatory mite species, Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) and Amblyseius swirskii (AnthiasHenriot), with T. urticae as the host, under laboratory conditions. The results showed that F. acarisuga was highly effective and the two species of predacious mites were moderately effective in feeding on T. urticae eggs. Logistic regression analysis suggested Type II (convex) functional responses for all three species. However, based on the estimates of the handling time and the attacking rates, the three predators had different predation capacities. Among the three species, F. acarisuga had the highest predation on T. urticae. The maximum daily predation by a larval F. acarisuga was 50 eggs/day, followed by a female N. californicus (25.6 eggs/day) and a female A. swirskii (15.1 eggs/day). A female N. californicus produced more eggs than a female A. swirskii did when they both fed on T. urticae eggs. In addition, all three predator species had no preystage preference for either prey eggs or nymphs. The findings from this study could help select better biological control agents for effective control of T. urticae and other pests in vegetable productions.

Show MeSH
Related in: MedlinePlus