Figure 2.

Appearance of tephritid fruit flies in Californian cities. (a) Event-history chart depicting the cumulative number of Californian cities that experienced one or more fruit fly infestations from 1950 to the present. Each horizontal line represents a Californian city, and coloured ticks depict the year in which one or more species was detected. Inset situates this schematic in a 100+ year context (California became a state in 1850). (b) Cumulative number of new Californian cities from which a detection of one of four different fruit fly species was reported. The abrupt levelling of the trajectory for C. capitata at 150 cities infested occurred at the same time that the California medfly preventive release programme was implemented in 1996.