THE FUTURE OF THE MEDITERRANEAN FRUIT-FLY CERATITIS-CAPITATA INVASIONOF CALIFORNIA - A PREDICTIVE FRAMEWORK

The objective of this paper is to predict the state-wide invasion patt erns and eventual distribution and abundance of the Mediterranean frui t fly Ceratitis capitata in California if current eradication efforts fail. The predictions are based on four assumptions: (1) the medfly is established in the state; (2) existing eradication technologies are i nadequate; (3) no new and effective eradication technology will be dev eloped in the near future; and (4) the population will not become exti nct due to natural causes. Based on climatic, agricultural and demogra phic information and historical capture patterns, the invasion is pred icted to progress in five stages, the first two of which are already c ompleted: Phase I-Introduction and establishment (in Los Angeles Basin and Bay Area); Phase II-Range expansion within LA Basin and Bay Area; Phase III-Escape from LA Basin/Bay Area and spread along Pacific coas t; Phase IV-Colonization of the interior; and Phase V-Invasion complet ion. The highest medfly populations will probably occur along the sout h coast region of Los Angeles and San Diego as well as in the southern San Joaquin Valley, high population densities will also likely exist along the central coast region (Santa Barbara to Santa Cruz), in the B ay Area and in the Sacramento Valley. Low populations will exist along the north coast and populations will be rare or absent in Sierra Neva das and in the northeastern and southeastern regions. Generalizations and implications for biology are discussed. Copyright (C) 1996 Elsevie r Science Limited