First record of Pediacus dermestoides (Fabricius, 1792) (Coleoptera: Cucujidae) for Bulgaria

The saproxylic species Pediacus dermestoides (Fabricius, 1792) is reported from forest habitats located in five mountains in Bulgaria. The adult beetles were found under the bark of several host tree species or captured with flight interception traps. It seems that P. dermestoides might be widespread in the mountain forests in Bulgaria.

Two genera of the family Cucujidae occur in the Palaearctic: Cucujus Fabricius, 1775 and Pediacus Shuckard, 1839 (Wegrzynowicz, 2007). In Europe, C. cinnaberinus Scopoli, 1763 is a threatened species (Cálix et al., 2018). Recently the species was firstly reported or confirmed for a number of Balkan countries, including Bulgaria (e.g. Guéorguiev et al., 2008;Kulijer & Miljević, 2017;Gjorgjievska et al., 2020). The species of the genus Pediacus are less intensively studied by researchers and no records have been available for Bulgaria until now. In the present work the species P. dermestoides (Fabricius, 1792) is reported for the first time for the country.

Methods
The material for the present study was collected spo-
All the specimens examined were collected as adults. The species can be recognised by the shape of the pronotum, shape of the antennomeres and the morphology of the aedeagus (Thomas, 2003). The adults of Pediacus can be distinguished from those of Cucujus by a number of characters, listed by Guéorguiev et al. (2008).
In Mainland Europe, the genus Pediacus is represented by the species P. depressus (Herbst, 1797), P. dermestoides (Fabricius, 1792) and P. fuscus Erichson, 1845 (Wegrzynowicz, 2007;Marris & Ślipiński, 2014). The diagnostic morphological characters of the three species are summarised and illustrated by Thomas (2003). All three species have a relatively wide distributional range (Wegrzynowicz, 2007) but only P. dermestoides (Fabricius, 1792) has been recently reported from SE Europe (a single finding from North Macedonia) (Guéorguiev et al., 2010). The present re-cord of the species is the first one for Bulgaria and the second for the Balkan Peninsula.
Biology of the genus Pediacus is insufficiently studied (Marris & Ślipiński, 2014). Species of the genus are found under the bark of dead coniferous and deciduous trees (Thomas, 2003;Marris & Ślipiński, 2014). The species P. dermestoides is classified as "Data Deficient" in the European Red List of Saproxylic Beetles (Nieto & Alexander, 2010;Cálix et al., 2018). In North Macedonia, the species was collected under the bark of Platanus orientalis L. (Guéorguiev et al., 2010). In the present paper, we report the association of P. dermestoides with the tree species Pinus sylvestris, Pseudotsuga menziesii and Sorbus domestica. A number of studies have shown that the flight interception traps are effective for monitoring of C. cinnaberinus populations (e.g. Schlaghamerský et al., 2008;Vrezec et al., 2012). We demonstrate that they are also suitable for collecting representatives of the genus Pediacus as well. Denis Gradinarov, Ognyan Sivilov, Danail Doychev In two of the reported in the present study five localities, Peshtera and Chiflik Vill. (Fig. 2A, B) another species of the family, C. cinnaberinus, was found in previous studies (Bekchiev et al., 2018). Probably P. dermestoides is a widespread in the mountain forest habitats with dead wood retention in the country. Its populations appear to exist in low numbers in Bulgaria and it has been overlooked in previous studies. The distributional map, based on reported localities of the species in Bulgaria, is presented in Fig. 3.