As part of the „Saproxylic insect conservation in the Carpathians” Life Rosalia project, we started installing wooden boxes filled with decaying plant material.
The boxes with decomposing plant material are mounted on the radius of the Putna Vrancea Natural Park. They mimic bark beetles and provide a large amount of dead wood for the reproduction of saproxylic insects that colonize the nutrient-rich cavities in the trees. The boxes have a volume of about 40 liters, and the vegetable compost imitates a substrate normally used by saproxylic insects: 60% sawdust (of the host plant), 30% dry leaves of the host plant (beech or oak), 10% chopped hay small, 500 ml lucerne flour, 500 ml oats, 5 L water and two or three pieces of wood.
One of the insects which we hope will colonize these boxes is Osmoderma eremita, an indicator species for deciduous tree ecosystems. It is a species with very low densities that does not cause economic damage to wood, feeding exclusively on rotting wood. The hermit beetle is a species protected by the Habitats Directive (priority species, listed in Annexes II and IV) and by Emergency Ordinance no. 57/2007 regarding the regime of natural protected areas, conservation of natural habitats, of flora and fauna. It is considered to have a favorable conservation status in Romania (period 2013-2018), but this is due to the overestimation of the area that can be occupied by this species.