Investigation of the effect of needle traits on pine processionary moth host preference in Turkish red pine

Turkish red pine (Pinus brutia Ten.) is an economically and ecologically important species that plays a critical role in Turkey's forest ecosystem. However, this red pine forest is threatened by the pine processionary moth (Thaumetopoea wilkinsoni Tams.), a pest that is especially widespread in the Mediterranean Basin and in pine forests in Turkey. The moth can cause serious damage to the forest ecosystem by feeding on the needles of pine trees. This thesis aims to better understand the mechanism of pine processionary moth (PPM) infestation in P. brutia. Determining the visual cues that PPM uses in its host preference is a key focus of this study. Within the scope of this thesis, detailed analyses of photosynthetic pigment content, specific leaf area and color scales of needles were carried out in P. brutia genotypes that are resistant and non-resistant to PPM infestation. The results of the analysis revealed that leaf specific area, chlorophyll-a, chlorophyll-b, total chlorophyll and carotenoid values were higher in infested clones than in non-infested clones. Statistically significant differences in these values were observed especially in the late summer and fall months (August, September, October and November) when the larval period of the insect is the most intense. The our results suggest that PPM may also use visual cues of clones/trees in host selection. The data obtained in this study should contribute to the ecological literature on PPM.