Applied Entomology and Zoology (1998) 33, 391-399

K. Takasu, Y. Hirose and M. Takagi (1998)
Occasional interspecific competition and within-plant microhabitat preference in egg parasitoids of the bean bug, Riptortus clavatus (Hemiptera : Alydidae) in soybean
Applied Entomology and Zoology 33 (3), 391-399
Abstract: We examined the occurrence of interspecific competition among egg parasitoids of Riptortus clavatus (Thunberg) (Hemiptera: Alydidae) in within-plant microhabitats of soybean fields in Fukuoka during the planting seasons from 1985 to 1987. R. clavatus eggs were found mainly on leaves and pods, and rarely on stems of soybean plants. They were parasitized by Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae), Gryon japonicum (Ashmead) and G. nigricorne (Dodd) (Hymenoptera: Scelionidae). During three planting seasons, O. nezarae was more abundant than Gryon spp. O. nezarae parasitized more than 70% of hosts on leaves but less than 50% of those on stems and pods. Gryon spp., especially, G. nigricorne, parasitized more hosts on pods than on leaves or stems. Multiparasitism by O. nezarae and Gryon spp. rarely occurred in hosts from all three parts of the plant. Exploitation competition was more likely to occur in the early part of the season during 1985 and 1986 when overexploitation by O. nezarae was likely to reduce reproduction of Gryon spp. in soybean. Since interspecific competition was infrequent, the different parasitism patterns by O. nezarae and Gryon spp. on various plant parts were probably, due to their differences in microhabitat preference.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Keiji Takasu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
general biology - morphology - evolution
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Riptortus pedestris	Soybean (Glycine max)	Japan
Ooencyrtus nezarae (parasitoid)	Riptortus pedestris	Soybean (Glycine max)	Japan
Hadronotus japonicus (parasitoid)	Riptortus pedestris	Soybean (Glycine max)	Japan
Hadronotus nigricornis (parasitoid)	Riptortus pedestris	Soybean (Glycine max)	Japan