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Gall Structure Affects Ecological Associations of Dryocosmus kuriphilus (Hymenoptera: Cynipidae)

Permanent URL:
http://handle.nal.usda.gov/10113/43386
Abstract:
Gall wasps (Hymenoptera: Cynipidae) induce structures (galls) on their host plants that house developing wasps and provide them with protection from natural enemies. The Asian chestnut gall wasp, Dryocosmus kuriphilus Yasumatsu, is an invasive pest that is destructive to chestnut (Castanea spp.). An improved understanding of the interactions among D. kuriphilus, its host, and its natural enemies is critical for the development of effective management strategies against this pest. The objective of our study was to evaluate the D. kuriphilus community interactions, and relate these interactions to variations among gall traits. Galls were collected from four locations throughout the eastern United States from May (gall initiation) through August (after gall wasp emergence), and January. Gall characteristics (volume, weight, and schlerenchyma layer thickness), gall inhabitants (D. kuriphilus, parasitoids, and chamber fungi), and other community associates (insect herbivores and lesions thought to be caused by endophytes) were evaluated and correlated using canonical correlation analyses. The primary mortality factors for D. kuriphilus were parasitism, gall chamber-invading fungi, and failure of adult gall wasps to emerge. Larger gall size and thicker schlerenchyma layers surrounding the larval chambers were negatively correlated with parasitoids and chamber fungi, indicating these gall traits are important defenses. External fungal lesions and insect herbivory were positively correlated with the absence of D. kuriphilus within galls. This study provides support for the protective role of cynipid galls for the gall inducer, identifies specific gall traits that influence gall wasp mortality, and improves our knowledge of D. kuriphilus ecology in North America.
Author(s):
Cooper, W. Rodney , Rieske, Lynne K.
Subject(s):
Castanea , plant pests , insect pests , Dryocosmus kuriphilus , insect ecology , population ecology , microhabitats , galls , traits , sclerenchyma , ecological competition , parasitoids , herbivores , fungal diseases of plants , plant ecology , plant-insect relations , parasitism , seasonal variation , Eastern United States
Format:
p. 787-797.
Note:
Includes references
Source:
Environmental entomology 2010 June, v. 39, issue 3
Language:
English
Year:
2010
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
File:
Download [PDF File]
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.