Studio della vista di insetti xilofagi e integrazione di stimoli visivi in sistemi di trappolaggio per insetti scolitidi.

The presence of wood boring insects in forest ecosystems is of a paramount importance thanks to their contribution of the degradation of decaying or dead wood material, the creation of soil litter and the nutrients cycle speeding. Nevertheless, it can also cause severe economic losses during outbreaks, by inflicting widespread mortality at landscape scale on several tree species. Moreover, the introduction of alien species due to trading poses a significant threat to native local ecosystems. Nowadays, trapping systems used for monitoring rely almost exclusively on olfactory cues in the form of pheromones, able to attract insects in the nearby areas. Despite their extensive use, pheromone traps are sometimes of a relatively low efficiency for various factors. For this reason, this thesis work aimed to explore insect vision as a further sense able to improve already existing trapping systems efficiency and reliability. As knowledge in this field is limited, understanding visual sensory ecology could result crucial for developing more effective monitoring, management and surveillance strategies, particularly important in the first stage of an outbreak. This thesis examines two wood boring, the bark beetle Ips typographus (Coleoptera, Curculionidae, Scolytinae) and the longhorn beetle Arhopalus ferus (Coleoptera, Cerambycidae, Spondylidinae). In 2018, Vaia storm hit north-eastern Italian Alps and caused the subsequent I. typographus outbreak, highlighting the need of a more efficient trapping method, able to intercept higher number of individuals and to share real time captures data in order to plan prompt surveillance strategies in the affected forests. For this reason, we investigated the visual responses of I. typographus retina via electroretinography (ERG) recordings and through behavioural assays under controlled laboratory conditions. We tested visual preferences towards UV (370 nm) and green (530 nm) light, found to be those whom the bark beetle is sensitive to.