## 4 Discussion
### Determining the Spatial and Temporal SIT Opportunity Window
Model Sensitivity--Ability to Capture and Quantify the Impact of Even Minor Differences in Terrain Topography on the Development of Medfly and Performance of SIT  
To highlight the role of the spatial structure of the local terrain on the development of medfly population, and to demonstrate the model's ability to reflect and quantify such interactions, all three sites were assumed to have a similar structure and identical seasonal fruit assortment. They differed only in the spatial arrangement of fruit plots or in a relatively small change in the ratio occupied by different fruit phenological categories. Our simulations showed that even such small structural differences between sites severely affected the development and ultimately the size of the seasonal medfly population. Simple spatial rearrangement and consolidation of existing fruit plots into phenological blocks, in which mid-season and late fruits were separated by the zone with the earliest fruits, severely hampered medfly development. During the critical period of early spring, this reduced the chances of the few randomly scattered medfly founders to locate the earliest fruits and forced their progeny that emerged there to move and disperse far within bigger (consolidated) mid-season fruit block. Most importantly, later on, the fruitless and less attractive block of the earliest fruiting trees served as a buffer and hindered the medfly movement from the mid-season fruit to the less accessible and more distant late fruits. As a result, late fruits, which typically develop the largest populations in the annual cycle and are the main target of medfly attack, were less infested. Further modification of the reduced area occupied by very early and late fruits, although small, also had a measurable effect on medfly development. In addition to estimating target pest densities and determining temporal and spatial focal zones, designing a local SIT also entails decisions about the size of the sterile male cohorts to be released, and the frequency and method of release (e.g., uniform aerial vs. ground points). Although it seems intuitively obvious that increasing the number, frequency, and uniformity of male releases should improve the efficiency of the operation, quantifying the location-specific benefits in relation to the incurred effort and costs is not. The presented model reflects the influence of the local landscape structure on the behaviour of both wild females and released sterile males and allows for a quantitative estimation of the performance of different SIT scenarios. Our results confirmed the sensitivity of the model and its ability to detect, discriminate and quantify the impacts of relatively minor changes in local topography. Our simulations revealed that even seemingly small alterations in the spatial organization of the landscape and fruit arrangement can significantly affect medfly development and cause the performance of different SIT scenarios to change in a way that is not always consistent with intuitive expectations. It also showed that when planning local SIT activities, challenges should not be assessed solely on the basis of the general presence of host fruits, and that the influence of the spatial arrangement of local resources can be significant and cannot be ignored. The results generated by the model allow for informed decisions to be made, selecting of the most promising scenario and optimally tuning it to the local fruit and landscape structure, and site-specific weather conditions.