SEASONAL ABUNDANCE AND SPATIAL-DISTRIBUTION PATTERNS OF 3 ADULT MUSCOID (DIPTERA, MUSCIDAE) SPECIES ON EQUINE PREMISES

Adult face fly, Musca autumnalis De Geer, stable fly, Stomoxys calcitrans (L.), and horn fly, Haematobia irritans (L.), populations on four Kentucky horse farms were monitored weekly from late April to mid-October 1987 and 1988 using dry ice-baited canopy traps and visual counts of flies on pastured horses. Face flies were most abundant during May 1987 and June of both years followed by peak stable fly activity during mid-June, July, and August of both years and peak horn fly activity during mid-September of both years. Canopy trap collections of face flies were correlated with visual counts of face flies on pastured horses for 1987 and 1988. Horn flies were not collected in the canopy traps, and stable flies were not observed on pastured horses. Using visual count data to determine the degree of population aggregation, horn fly populations were found to be more contagious than face flies as populations increased on pastured horses. From the canopy trap data, face fly and stable fly populations had similar aggregation indices or similar distribution patterns as populations increased. © 1990 Entomological Society of America.