"Effects of host trees on colonization patterns by ambrosia beetles under different abiotic stressors"

Ambrosia beetles are polyphagous insects able to attack several broadleaf tree species causing damages. They mainly attack weakened trees attracted by the emission of ethanol from the plant. Adult females create tunnels into the stems and branches of host plants to create galleries with brood chambers and cultivate their own nutritional fungal symbionts on gallery walls. In order to better understand the colonization patterns of ambrosia beetles, an experiment has been set in the natural area of “Bosco Nordio”. Here we used potted trees of eight different species (four species from the order of the Fagales, and four from the Rosales order) which were randomly assigned to three different treatments: control, injection with ethanol, and flooding. The main objectives of this thesis are (i) to check whether colonization success of different ambrosia beetles changes depending on the tree species, and (ii) to describe if the latter trends change in the three treatments. Four different species of ambrosia beetles were identified: Xylosandrus crassiusculus, Xylosandrus germanus, Xyleborinus saxesenii and Xyleborus monographus. Main results showed a differential attractiveness of the eight tested tree species to the different ambrosia beetles and also that the injected plants were attacked more than the flooded ones.