Acta Entomologica Sinica (2004) 47, 342-348

Zu-Hua Shi, Qing-Bao Li, Xin Li and Shu-Sheng Liu (2004)
[Interspecific competition between Diadegma semiclausum (Hymenoptera : Ichneumonidae) and Cotesia plutellae (Hymenoptera : Braconidae) in parasitizing Plutella xylostella larvae]
Acta Entomologica Sinica 47 (3), 342-348
Abstract: Interspecific competition between two parasitoids, Cotesia plutellae (Kurdjumov)(Hymenoptera: Braconidae) and Diadegma semiclausum Hellen (Hymenoptera : Ichneumonidae), was investigated at 25°C in the laboratory, by exposing 3rd instar larvae of the diamondback moth, Plutella xylostella ( L.) ( Lepidoptera: Plutellidae) to both parasitoids together or either parasitoid alone, and by exposing the host larvae already parasitized to one of the parasitoid. When host larvae were exposed to both parasitoids in one arena, initial parasitism rates of the host by each species were not reduced by the presence of the other species; and the final joint parasitism rate by the two species was not significantly higher than that by either parasitoid alone. Both parasitoids could lay eggs into host larvae previously parasitized by the other species, leading to occurrence of multiparasitized hosts. When host larvae were parasitized first by D. semiclausum and then immediately exposed to C. plutellae, or parasitized first by C. plutellae and then immediately exposed to D. semiclausum, nearly all ensuing parasitoid adults from the multiparasitized host larvae were C. plutellae. When host larvae parasitized by C. plutellae > 2 days earlier were exposed to D . semiclausum, all ensuing parasitoids from the multiparasitized hosts were of C. plutellae. When host larvae parasitized by D. semiclausum > 2 days earlier were exposed to C. plutellae, most host larvae could not survive to prepupae and most of the ensuing parasitoid adults from the hosts that supported successful parasitism were D. semiclausum. Dissections of host larvae at various time intervals after initial parasitism by both parasitoids showed that development of both parasitoids in multiparasitized hosts were somewhat arrested.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Chinese)
Database assignments for author(s): Zu-Hua Shi, Shu-Sheng Liu

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
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.
	Plutella xylostella
Cotesia vestalis (parasitoid)	Plutella xylostella
Diadegma semiclausum (parasitoid)	Plutella xylostella