Activity and relative abundance of hymenopterous parasitoids that attack puparia ofMusca domesticaandStomoxys calcitrans(Diptera: Muscidae) on confined pig and cattle farms in Denmark

Abstract

AbstractA survey was conducted on 84 pig and cattle farms in Denmark between August and October 1996 and 1997. The aim was to describe the activity and relative abundance of parasitoids (Hymenoptera: Pteromalidae and Ichneumonidae) that attack puparia ofMusca domesticaLinnaeus andStomoxys calcitrans(Linnaeus). In total, seven pteromalid species were recovered:Spalangia cameroniPerkins,S. nigripesCurtis,S. subpunctataFörster,Muscidifurax raptorGirault & Sanders,Pachycrepoideus vindemiae(Rondani),Urolepis rufipes(Ashmead) andNasonia vitripennis(Walker), an ichneumonidPhygadeuon fumatorGravenhorst, a diapriidTrichopriasp., and a staphylinidAleocharasp. This is the first time thatU. rufipeshas been recorded in Europe.Spalangia cameroniandM. raptorwere the most frequently recorded species in all regions of the country, and accounted for the main parasitism ofMusca domesticaandStomoxys calcitranspuparia. The overall rate of parasitism per farm was low: 12.9% of the total number of fly puparia collected. Direct ordination, used to assess the habitat distribution of the parasitoids, showed thatMuscidifurax raptormainly seeks fly puparia in outdoor manure heaps and especially in manure from pigs rather than from cattle, whereasSpalangia cameronimainly seeks fly puparia indoors, irrespective of livestock.