Microhabitat Associations of Hymenopterous Parasitoids that Attack House Fly Pupae at Dairy Farms in Central New York

Abstract

Samples of laboratory-reared fly pupae were exposed weekly throughout the fly-breeding season for 2 yr at eight dairy farms. Microhabitats were classified by type of location, substrate, exposure (to sunlight and weather), and substrate moisture content. Total parasitism was fairly evenly distributed over all types of fly-breeding microhabitats; however, several parasitoid species exhibited strong associations with specific types of microhabitats. Muscidifurax raptor Girault and Sanders was most abundant in feed and straw, and occurred primarily at outdoor sites (regardless of moisture), and dry sheltered or indoor sites. Phygadeuon fumator Gravenhorst was most abundant in calf bedding, particularly at moist or wet indoor or sheltered sites, which was where M. raptor was not abundant, and outdoor feed. Spalangia cameroni Perkins occurred primarily indoors, regardless of moisture, but preferred loose substrates such as straw and calf bedding. Spalangia nigroaenea Curtis was most common in sheltered moist feed and indoor wet straw. Urolepis rufipes (Ashmead) was most common at wet outdoor sites, primarily at manure lagoons and manure piles. Trichomalopsis dubius (Ashmead) was collected exclusively outdoors, primarily at earth and grass substrates near manure lagoons and manure piles.