## 3 Results
### Olive Fruit Fly Infestation of the Drupes
The graph displays the changes in the percentage of punctured drupes (panel **A**), drupes with a fertile puncture (panel **B**) and a sterile puncture (panel **C**) over time. Each cultivar is represented by a different symbol and color. In all the cultivars, the percent of %PDtot increased, according to a quadratic function with drupe diameter (dd) with the exception of 'Nocellara etnea', for which the relationship was linear (Frantoio': %PDtot = 3.94 dd \({}^{2}-66.34\) dd + 276.88, R\({}^{2}\) = 0.70, \(p\) = 0.049; 'Leccino': %PDtot = 2.80 dd\({}^{2}-36.74\) dd + 102.24, R\({}^{2}\) = 0.82, \(p\) = 0.015; 'Nocellara etnea': %PDtot = 12.69 dd \({}-122.8\), R\({}^{2}\) = 0.96, \(p<0.001\); 'Nocellara mesinese': %PDtot = 2.57 dd\({}^{2}-72.85\) dd + 513.36, R\({}^{2}\) = 0.93, \(p\) = 0.001; 'Pendolino': %PDtot = 1.73 dd\({}^{2}-22.40\) dd + 68.9, R\({}^{2}\) = 0.87, \(p\) = 0.006; 'Sant'Agostino': %PDtot = 2.15 dd\({}^{2}-58.82\) dd + 416.41, R\({}^{2}\) = 0.97, \(p\) < 0.001) (Figure 3A). These relationships were similar among 'Frantoio', Leccino', and 'Pendolino'. The %PDfert also increased according to a quadratic function with drupe diameter, with the only exception being 'Frantoio' and 'Pendolino', for which these parameters were related according to a positive linear relationship ('Frantoio': %PDfert = 12.61 dd \(-\) 115.12, R\({}^{2}\) = 0.52, \(p\) = 0.042; 'Leccino': %PDfert = 5.18 dd\({}^{2}-90.60\) dd + 393.86, R\({}^{2}\) = 0.83, \(p\) = 0.012; 'Nocellara etnea': %PDfert = \(-\)1.24 dd\({}^{2}+40.01\) dd \(-\) 272.91, R\({}^{2}\) = 0.96, \(p\) < 0.001; 'Nocellara mesinese': %PDfert = 1.29 dd\({}^{2}-35.47\) dd + 241.69, R\({}^{2}\) = 0.97, \(p\) < 0.001; 'Pendolino': %PDfert = 7.27 dd \(-\) 57.56, R\({}^{2}\) = 0.75, \(p\) = 0.006; 'Sant'Agostino': %PDfert = 3.71 dd\({}^{2}-115.11\) dd + 896.26, R\({}^{2}\) = 0.91, \(p\) = 0.002) (Figure 3B). These relationships were similar between 'Frantoio' and Leccino' and between 'Sant'Agostino' and 'Nocellara mesinese'. The %PDster increased with fruit diameter only in 'Nocellara etnea' and 'Pendolino' (a quadratic and linear relationship, respectively) ('Nocellara etnea': %PDster = 1.15 dd\({}^{2}-25.17\) dd + 137.50, R\({}^{2}\) = 0.84, \(p\) = 0.011; 'Pendolino':  
Figure 3: Relationship between the diameter of the drupe and the occurrence of (**A**) punctures (both fertile and sterile), (**B**) fertile punctures, and (**C**) sterile punctures caused by the olive fruit fly. Only significant regression curves (\(p\leq 0.05\)) were reported. \(\%\)PD\({}_{\text{ster}}\) = 2.38 d \(-\) 19.07, R\({}^{2}\) = 0.58, \(p\) = 0.028), whereas for the other cultivars, these two parameters were not related by linear or quadratic relationships (Figure 3C). We performed a PCA to summarize the multivariate dataset in a reduced number of variables and graphically illustrate the relationships among the cultivars. Among the five extracted principal components (PCs), the first three had an eigenvalue higher than 1, and altogether explained the vast majority (95.8%) of the total variance (Table 2), suggesting that the observed phenomena can be largely described by a small number of underlying factors. PC1 and PC2, which captured 86.3 of the total variance, were retained to visualize the cultivar resemblance (Figure 4). The cultivars appear scattered and spread out in the different quadrants, without any obvious clusters or trends related to drupe size or susceptibility. For instance, the two cultivars with the bigger drupes, 'Sant'Agostino' and 'Nocellara messinese', had distinct positions on PC1 and PC2, respectively. On the other hand, the closest varieties in the plot ('Frantoio' and 'Nocellara etnea') have very similar infestation levels. All this can be explained considering that the observed relationships among the measured parameters are non-linear; hence, they are not well-captured by the PCA.