title: An agent-based simulation of extirpation ofCeratitis capitataapplied to invasions in California.
abstract: We present an agent-based simulation (ABS) ofCeratitis capitata("Medfly") developed for estimating the time to extirpation of this pest in areas where quarantines and eradication treatments were immediately imposed. We use the ABS, implemented in the program MED-FOES, to study seven different outbreaks that occurred in Southern California from 2008 to 2010. Results are compared with the length of intervention and quarantine imposed by the State, based on a linear developmental model (thermal unit accumulation, or "degree-day"). MED-FOES is a useful tool for invasive species managers as it incorporates more information from the known biology of the Medfly, and includes the important feature of being demographically explicit, providing significant improvements over simple degree-day calculations. While there was general agreement between the length of quarantine by degree-day and the time to extirpation indicated by MED-FOES, the ABS suggests that the margin of safety varies among cases and that in two cases the quarantine may have been excessively long. We also examined changes in the number of individuals over time in MED-FOES and conducted a sensitivity analysis for one of the outbreaks to explore the role of various input parameters on simulation outcomes. While our implementation of the ABS in this work is motivated byC. capitataand takes extirpation as a postulate, the simulation is very flexible and can be used to study a variety of questions on the invasion biology of pest insects and methods proposed to manage or eradicate such species.
authors.affiliation: US Pacific Basin Agricultural Research Center, United States Department of Agriculture-Agricultural Research Service, Hilo, HI USA.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Manoukis
authors.affiliation: California Department of Food and Agriculture, Sacramento, CA USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Hoffman
keywords: Agent-based modeling; Medfly; Model; Quarantine; Simulation