## 4 Discussion
### Performance of Sterile Males After Their Release  
The success of the SIT operation depends crucially on the behaviour and quality of the released sterile males [3]. Their pre-release quality is routinely tested as part of the monitoring of the mass production process. However, these tests, conducted in laboratory conditions or in field cages, although valuable, do not fully reflect the performance of sterile males after their release under more challenging field conditions. Surprisingly, empirical data on the performance of males under realistic field conditions are scarce. Estimates of the fraction of active flyers emerging from pupae batches range from about 50% [30] to over 70% reported in our discussions with operators of large mass-rearing facilities. Post-release survival and dispersal distances can be inferred from the results of numerous recapture  
Figure 8: The influence of the size of the sterile male cohort and the method of their release on the reduction in the annual medfly population peak. studies [28; 29; 30; 31; 32; 33; 34]. In general, the analysis of available data indicates that at least 50% of males would survive three, and possibly four, days after release. The range explored by most released sterile flies does not exceed 100-200 m, and more than 90% do not venture further than 400-500 m from the release point [32]. Released males actively follow the distribution of locally available resources and even when released from evenly spaced points, their aggregation areas tend to mirror those of wild males [19]. The least studied aspect concerns the interactions and mating competition between sterile and wild males under field conditions. It is known that in field cages or semi-field conditions with a rather basic canopy of potted or pruned fruit trees, sterile males tend to function quite well and, if present in equal numbers to wild males, can achieve 20-25 or even 35% of matings [36; 37]. However, in a field study of strain Maui-03, [PERSON] and [PERSON] [35] reported that wild males had a mating rate of 91%, although in leaks formed by sterile and wild males, the latter contributed only 19%. Overall, for strains like Maui-97, it can be estimated that the percentage of successful males from batches of irradiated pupae is about 12-13% in field cages and about 4% in the field [36]. For the improved and now widely used Vienna-8 strain, these numbers have been estimated to be about two to three times higher. In most cases, copulation with sterile males causes the female not to mate again [40], although cases of re-mating with another male, wild or sterile, do occasionally occur [41]. The frequency of such events for the Vienna-8 strain used in our simulations has been estimated at about 5%. The parameters that were used in the presented simulations were estimated based on the analysis of available and published empirical data and discussions with experts involved in large-scale SIT operations. However, the performance parameters of sterile males are not fixed in the model and can be set by the user to reflect the quality of the simulated medfly strain. Individual-Based Modelling Approach and Outline of Specific Features of the SIT-Enhanced PESTonFARM Model  
Consistent with the original concept of SIT implementation, available decision support tools and models focus on interventions at large spatial scales on the order of several or thousands of square kilometers that cover the area of most or all of the targeted medfly population [42]. Typically, such models are based on deterministic mathematical equations or algorithms that estimate the effects of various aspects of SIT intervention on the generalized growth of the target pest population [23]. Although they answer general questions about SIT and are useful in planning large-scale operations, they tend to ignore the influence of fine-grained terrain structures and their impact on the behavior of both wild and released sterile medflies [23].