Filth fly parasitoids on dairy farms in Ontario and Quebec, Canada

Hymenopterous parasitoids of filth flies (Diptera: Muscidae) were surveyed during 2 years on dairy farms in Ontario and Quebec near Ottawa, Ontario, using freeze-killed sentinel house fly (Musca domestica L.) pupae and naturally occurring fly pupae collected on site. Musca domestica and Stomoxys calcitrans (L.) (stable fly) represented 98.3% of the natural fly hosts from which parasitoids emerged. Muscidifurax raptor Girault et Saunders, Nasonia vitripennis Walker, Pachycrepoideus vindemiae (Rondani), Spalangia cameroni Perkins, S. nigra Latreille, Trichomalopsis viridescens (Walsh), and Urolepis rufipes (Ashmead) (Pteromalidae) were recovered from both sentinel and natural fly pupae. Another eight species, S. drosophilae Ashmead, S. endius Walker, S. haematobiae Ashmead, S. nigroaenea Curtis, S. subpunctata Förster, Trichomalopsis dubia (Ashmead) (Pteromalidae), Aphaereta pallipes (Say) (Braconidae), and Phygadeuon ?fumator Gravenhörst (Ichneumonidae), were recovered only from natural pupae. Over the 2 years, M. raptor comprised 90.7% of emerged parasitoids from sentinel pupae but only 17.0% of emerged parasitoids from natural pupae. From natural pupae, S. cameroni, S. nigra, and S. nigroaenea collectively comprised 60.3% of emerged parasitoids; P. ?fumator comprised 13.5% and the remaining nine species 9.2%. The recoveries of S. endius and S. nigroaenea represent new distribution records for Canada, and several new host records are identified based on structure of the host fly puparium. The parasitoid fauna is compared with that known for western Canada, and recommendations are made for both regions concerning potential natural enemy enhancement for filth fly control. Gibson GAP, Floate KD. 2004. Les parasitoïdes des mouches des immondices dans des fermes laitières de l’Ontario et du Québec, Canada. The Canadian Entomologist 136 : 407–417. Résumé—Nous avons fait pendant 2 ans l’inventaire des hyménoptères parasitoïdes des mouches des immondices (Diptera : Muscidae) sur des fermes laitières de l’Ontario et du Québec près d’Ottawa, Ontario, en utilizant des pupes sentinelles de mouches domestiques (Musca domestica L.) tuées au froid et des pupes de mouches présentes naturellement sur les lieux. Musca domestica et Stomoxys calcitrans (L.), la mouche des étables, constituent 98,3 % des hôtes naturels desquels les parasitoïdes ont émergé. Les ptéromalidés Muscidifurax raptor Girault et Saunders, Nasonia vitripennis Walker, Pachycrepoideus vindemiae (Rondani), Spalangia cameroni Perkins, S. nigra Latreille, Trichomalopsis viridescens (Walsh) et Urolepis rufipes (Ashmead) ont été obtenus à partir des pupes de mouches, tant sentinelles que naturelles. Huit autres espèces, les Ptéromalidés S. drosophilae Ashmead, S. endius Walker, S. haematobiae Ashmead, S. nigroaenea Curtis, S. subpunctata Förster, Trichomalopsis dubia (Ashmead) (Pteromalidae), Aphaereta pallipes (Say) (Braconidae) 407 1 Corresponding author (e-mail: [email protected]). I:\ent\ent13603\N03-006.vp May 11, 2004 9:34:57 AM Color profile: Disabled Composite Default screen