Stable flies,Stomoxys calcitrans(L.), were offered one, two, or ad libitum meals of citrated bovine blood on a daily basis in combination with nectar (a 1:3 dilution of wild honey in water) at levels of none, one, or ad libitum each day. Reproduction during a 12-d period was depressed with ad libitum nectar to as low as 35% of flies receiving nectar once per day or not at all. Direct interference with blood hunger appeared to occur in nectar-fed stable flies. Female survivorship decreased 21–29% among flies receiving ad libitum nectar. Flies given blood ad libitum produced>55 and 40% more eggs than flies offered blood once or twice per day. In a separate experiment, the survivorship of adult flies given dilutions of purified sugars was measured. Statistically, the highest mean survival time was 8 d for flies fed trehalose, 5 times the length allowed by water alone. Fructose and melezitose were next, with life spans that were ≍4 times that of water-fed flies. Maltose, raffinose, glucose, sucrose, and melibiose meals extended life spans from 3 to 2 times that of water. The disturbance to reproduction that results from nectarophagous activities is discussed in view of the normal field activities of the species.