Host Blood Meal Identification by Multiplex Polymerase Chain Reaction for Dispersal Evidence of Stable Flies (Diptera: Muscidae) Between Livestock Facilities

A species-specific multiplex polymerase chain reaction targeting the cytochrome b gene of cattle, horses, humans, and dogs was developed to determine the blood meal sources of stable flies, Stomoxys calcitrans (L.), collected from Florida equine facilities. Of 595 presumptive blood-fed stable flies analyzed, successful host amplification was obtained in 350, for a field host-detection efficiency of 58.8%. The majority of analyzed stable flies had fed on cattle (64.6%), followed by horses (24.3%), humans (9.5%), and dogs (1.6%). A survey of animal-enclosed pastures occurring within 3 km of stable fly collection sites revealed that the nearest cattle were between 0.8 and 1.5 km from the four horse farm sampling sites. Cattle-feeding frequencies were greater on farms where cattle were located at distances of 0.8 km, suggesting that between farm differences in host-feeding frequency is related to the number of and distance from a particular host type. Time course evaluations of previously laboratory-fed stable flies demonstrated that host-detection efficiency with this system was 100, 50, and 0% when flies were evaluated at 16, 24, and 48 h postblood feeding, respectively. The results of this study suggest short-term stable fly dispersal of up to 1.5 km in a 48-h time period. The implications of these findings are discussed.