Over the last four summers (2001 - 2004), the olive fly (OLF), Bactrocera oleae (Gmelin), has posed a major threat to table olives produced in California’s Central Valley. Growers spray insecticide baits weekly for control. Monitoring of adult OLF populations via sticky traps shows that adult numbers decline to low levels in mid-summer, even in the absence of insecticide treatments. High summer temperatures (e.g., 95 – 110°F) are thought to contribute to the decline in OLF numbers. Laboratory studies indicate that adult female OLF may die when exposed to daily high temperatures at or above 95°F for two or more days. The percentage of flies that die are mainly influenced by the availability of water and honey. Adult survival was high only when both water and honey were available. Water alone was not sufficient to sustain the flies over 5 days at 95°F. Combinations of honey + olives and water + olives resulted in high mortality by Day 4 in all temperatures tested above 95°F. Female adult behavior changed dramatically at high temperatures. Under heat stress, females remained on dental wicks that provided water while temperatures were high. This behavior also may contribute to reduced numbers of flies recorded on sticky traps during the summer.