Experimental and Applied Acarology (2014) 63, 205-215

Tetsuo Gotoh, Masumi Hanawa, Sayaka Shimazaki, Natsuki Yokoyama, Chun-Qing Fu, Reo Sugawara and Shuichi Yano (2014)
Factors determining species displacement of related predatory mite species (Acari: Phytoseiidae)
Experimental and Applied Acarology 63 (2), 205-215
Abstract: Neoseiulus womersleyi (Acari: Phytoseiidae) used to be the dominant species in fruit-tree orchards throughout Japan, but starting in the 1990s, N. womersleyi began to be displaced by Neoseiulus californicus in central and southwestern Japan. The present study was conducted to examine factors explaining the displacement of N. womersleyi by N. californicus. First, we confirmed under laboratory conditions that N. californicus could exclude N. womersleyi if they initially coexisted in a 1:1 ratio. During a 2-h continuous observation period, none of the heterospecific pairs had copulated and after 5 days together with heterospecific males, none of the females had laid eggs. When these females were placed with conspecific males, normal numbers of offspring were produced. Moreover, conspecific matings were not substantially disturbed in the presence of heterospecific males or females. Total fecundity was significantly lower in N. womersleyi than in N. californicus, but their r_m values did not differ from each other. On the other hand, the frequency of intraguild predation by N. californicus on N. womersleyi was significantly higher than vice versa. From these results, we concluded that not reproductive interference nor differential female fecundity but asymmetrical intraguild predation seemed to explain the competitive exclusion of N. womersleyi by N. californicus.
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Link to article at publishers website
Database assignments for author(s): Tetsuo Gotoh, Shuichi Yano

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
population dynamics/epizootiology
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Tetranychus urticae		Japan
Neoseiulus californicus (predator)	Tetranychus urticae		Japan
Neoseiulus womersleyi (predator)	Tetranychus urticae		Japan