Field studies of Entomophthora (Zygomycetes : Entomophthorales) - induced behavioral fever in musca domestica (Diptera : Muscidae) in Denmark

House flies were collected over 3 days (three to five times per day) from s pecific sites on a dairy farm with a range of high to low temperatures. Fli es were held individually to determine whether the distribution of fungus-i nfected (Entomophthora muscae and E, schizophorae) house flies differed acc ording to the stage of infection and temperature. All but 2 of 396 infected flies (99.5%) had E, muscae. More E, muscae-infected flies collected from cool areas were in later stages of infection (i,e,, dying 0-2 days after ca pture), whereas flies collected on sun-exposed surfaces tended to be in ear lier stages of infection (i,e,, dying 6-8 days after capture). Most flies d ied 3-5 days after capture and were consequently in the middle stages of in fection. A mark and release experiment was conducted to determine whether E , schizophorae-inoculated flies frequented surfaces with higher temperature s than did uninfected control flies. About 3000 yellow-marked house flies i noculated with E, schizophorae and 3000 blue-marked control flies were rele ased in an enclosed swine farrowing barn. Significantly more inoculated fli es were recorded on the heat lamps than flies in the control group. The res ults suggest that behavioral fever occurs in the field for flies infected w ith both E, muscae and E, schizophorae and that flies can cure themselves o f infection through the use of artificial heat sources. e zool Academic Pre ss.