Survival of horn flies according to time of dung deposition by cattle

Cowpats were flagged after deposition on pasture at 0500, 1100, 1700, and 2300 h and exposed to natural enemies for 6 h or 6 d. Sixty-one percent of horn flies emerging from pats exposed for 6 h emerged from cowpats dropped at 2300 h and exposed between 2300 and 0500 h when little or no flight activity by natural enemies occurred. Fifteen percent of the horn flies trapped from cowpats exposed 6 h emerged from pats dropped at 0500 h, 14% from pats dropped at 1100 h, and 10% from pats deposited at 1700 h. From cowpats exposed to natural enemies for 6 d, 52% of the horn flies emerged from pats deposited at 2300 h, 23% from pats dropped at 0500 h, 17% from 1100 h deposits, and 8% from 1700 h deposits. Mean numbers of dung beetles, predator beetles, and flies other than horn flies obtained from cowpats after both periods of exposure are discussed.