Table 3 Information about the distribution, biology and Red List category of threat of the species surveyed

Cetonia carthami aurataeformis Curti 1913 (Scarabaeidae: Cetoniidae)

Endemic subspecies of the Iberian Peninsula [42]

Larvae feed on wood and litter in tree hollows [43], while adults are flowers and fruits visitors [44]. This species has been considered an obligate species of tree hollows [33] and an ecosystem engineer^a of these peculiar microhabitats in Mediterranean forests [46]

–

Protaetia (Potosia) cuprea (Fabricius, 1775) (Cetoniidae)

Paleartic species [44]

Larvae have been considered facultative inhabitants of tree hollows while adults are flowers and fruits visitors [33, 44]

–

Protaetia (Eupotosia) mirifica (Mulsant, 1842) (Cetoniidae)

Rare species with Mediterranean distribution [47]

Larvae are obligate inhabitants of tree hollows [33]. Adults are often attracted by sugary resources

Vulnerable [23, 48, 49]

Elater ferrugineus Linnaeus, 1758 (Elateridae)

Western Palearctic species [50]

Larvae and adults are obligate inhabitants of tree hollows. Adults are predators of other saproxylic insects, and larvae can additionally feed on wood mould in cavities [51, 52]. This species has been considered a good indicator of tree hollows beetle diversity [53]

Near threatened [23]

Ischnodes sanguinicollis (Panzer, 1793) (Elateridae)

Palearctic species [50]

This species is an obligate inhabitant of tree hollows. Larvae and adults are predators [39, 54]

Vulnerable [23]

Cerambyx welensii (Kuster, 1846) (Cerambycidae)

Palearctic species [55]

They are considered ecosystem engineers^a [45, 56].The larvae are strictly xylophagous, while adults feed mainly on tree exudates or do not feed [57]

Near threatened [23, 49]

Stictoleptura trisignata (Fairmaire, 1852) (Cerambycidae)

Endemic species of the Iberian Peninsula [58]

The larvae of this species are considered xylophagous in different species of Quercus [58], while adults are flower visitors [59]

Near threatened [60]