The Asian Longhorned Beetle is a ravenous insect tree pest. This feeding effectively cuts off the tree's food supply and starves it to the point. Facts, identification, behavior, habitat, diet, life cycle and more. Adult Asian longhorned beetles are less than 5 cm long and have a shiny black outer skeleton. Severely impacted trees may have exposed wood where larval feeding galleries (tunneling) is visible. Description of damage: Larvae damage the tree by eating. Research has been evaluating which tree species are most at risk from larval feeding in the invaded range. Bancroft et al. (), rearing larvae.