title: Changes in parasitoid communities over time and space: a historical case study of the maize pest Ostrinia nubilalis.
abstract: Understanding the ways in which human environmental modifications affect biodiversity is a key challenge in conservation planning, pest control and evolutionary ecology. Parasitoid communities, particularly those associated with agricultural pests, may be susceptible to such modifications. We document here changes in the larval parasitoid communities of Ostrinia nubilalis--the main pest of maize--and its sibling species O. scapulalis, based on two historical datasets, one collected from 1921-1928 and the other from 2001-2005. Each of these datasets encompasses several years and large geographical areas and was based on several thousands/millions of host larvae. The 80-year interval between the two datasets was marked by a decrease in O. nubilalis parasitism to about two thirds its initial level, mostly due to a decrease in the rate of parasitism by hymenopterans. However, a well balanced loss and gain of species ensured that species richness remained stable. Conversely, O. scapulalis displayed stable rates of parasitism over this period, with a decline in the species richness of its parasitoid community. Rates of parasitism and species richness in regions colonized by O. nubilalis during the 1950s were one half to one third those in regions displaying long-term colonisation by this pest. During the recent human activity-driven expansion of its range, O. nubilalis has neither captured native parasitoids nor triggered parasite spill back or spill over.
authors: Université de Pau et des Pays de l'Adour, Unité Mixte de Recherche 5254, Institut Pluridisciplinaire pour l'Environnement et les Matériaux, Equipe Environnement et Microbiologie, Centre National de la Recherche Scientifique, Pau, France. laurent.folcher@anses.fr
authors: Laurent
authors: L
authors: Folcher
authors: Denis
authors: D
authors: Bourguet
authors: Denis
authors: D
authors: Thiéry
authors: Laurent
authors: L
authors: Pélozuelo
authors: Michel
authors: M
authors: Phalip
authors: Alain
authors: A
authors: Weissenberger
authors: Nathalie
authors: N
authors: Eychenne
authors: Catherine
authors: C
authors: Regnault-Roger
authors: Marc
authors: M
authors: Delos
mesh_terms: D000818:Animals; D044822:Biodiversity; D016208:Databases, Factual; D004777:Environment; D049673:History, 20th Century; D049674:History, 21st Century; D006802:Human Activities; D007814:Larva / Q000502:physiology; D009036:Moths / Q000145:classification / Q000502:physiology*; D003313:Zea mays / Q000469:parasitology*