First Record of the Saproxylic Beetle Cossonus parallelepipedus (Coleoptera, Curculionidae) in Bosnia and Herzegovina

Balkan Peninsula is considered to be a hotspot of beetle biodiversity. Registering occurrence of saproxylic beetles is an important first step for expanding the general knowledge about saproxylic beetles as ecologically important insect species. Cossonus parallelepipedus is a European saproxylic species distributed from Iberian Peninsula in the west to Russia in the east, and from the Mediterranean in the south to Fennoscandia in the north. The first, and until now the only find of this species for the Balkan Peninsula is from Croatia. We report the first find of C. parallelepipedus in Bosnia and Herzegovina (BiH). In April 2020, larvae, pupae and imagoes were collected, in the central part of BiH, north of Sarajevo, on Zvijezda Mt. near Vareš from decaying moist wood in the lower part of a tree trunk of European silver fir, Abies alba. We expect that this species has a wider presence, especially in mountain areas in the central part of the country. Due to the similar environment conditions for other two European Cossonus species ( C. cylindrus and C. linearis) their presence is also possible.

The Structure of Saproxylic Beetle Assemblages in View of Coarse Woody Debris Resources in Pine Stands of Western Poland

Background: Resources of dying and dead trees, decaying fragments of stems, stumps and branches, i.e., coarse woody debris (CWD), are an important structural element of biocenoses and are drivers of biodiversity. The aim of this study was to describe assemblages of saproxylic beetles in pine stands of western Poland in view of dead wood resources. We present faunistic (species identity) and quantitative (species and individual counts) data from two types of stands: 1. unmanaged pine stands, in which no trees have been extracted for over 30 years, with processes connected with tree dying and self-thinning of stands being undisturbed, 2. managed pine stands, in which routine tending operations extracting trees are performed in accordance with forest management plans and naturally dying trees are removed in the course of tending and sanitary logging; Methods: Beetles were captured in the years 2013–2014 using window flight traps. Assemblages of saproxylic beetles were assessed based on the indices of dominance, diversity (the Shannon–Weiner index), and species richness (Margalef’s index) as well as the estimated habitat fidelity index, feeding habits, and zoogeographical distribution. Similarity between the assemblages was evaluated applying cluster analysis. Dependence between dead wood resources and the diversity and species richness indices were analysed; Results: A total of 2006 individuals classified to 216 species were captured. Assemblages show considerable similarity on the local scale. Higher values of species diversity indicators were observed in unmanaged stands, in which no sanitation cuttings are performed; Conclusions: The decision to refrain from sanitation logging in pine monocultures results in increased CWD resources, which nevertheless does not lead to a marked increase in the values of biodiversity indicators. Unmanaged stands were characterised by a high share of zoophagous, mycetophagous, and saproxylic species. In contrast, managed stands were characterised by a high share of xylophagous beetles.

Open datasets wanted for tracking the insect decline: let’s start from saproxylic beetles

We present six datasets of saproxylic beetles collected between 2012 and 2018 in Central and Southern Italian forests. Saproxylics represent one of the main components in forest ecosystems in terms of diversity, species richness and functional traits and, for this reason, they are an important target group for studying the modification of forests over time. The datasets consist of annotated checklists and were published on Zenodo repository. Overall, 1,171 records are published, corresponding to 918 taxa (taxonomy at species or subspecies level). The taxa are scarcely shared amongst the areas, 80.2% of them are exclusive, indicating that the beetle communities are substantially different. In consideration of the biodiversity crisis we are passing through, which is especially dramatic for the insects, we want to promotecollaboration amongst researchers for making datasets available in open repositories. This will improve the possibility for researchers and forest managers of analysing the state of species distribution that could serve for long-term studies on the variation of insect communities. We encourage repeating species assessment in the same localities in order to evaluate the trends in insect communities over time and space.

Do different growth rates of trees cause distinct habitat qualities for saproxylic assemblages?

In production forests, a common silvicultural objective is enhancing tree growth rates. The growth rate influences both mechanical and biochemical properties of wood, which may have an impact on dead wood inhabiting (i.e. saproxylic) species. In this study, we tested for the first time whether tree growth rates affect dead-wood associated assemblages in general and the occurrence of red-listed species in particular. We sampled saproxylic beetles (eclector traps) and fungi (DNA metabarcoding of wood samples) in dead trunks of Norway spruce (Picea abies), which had different growth rates within the same hemiboreal forests in Sweden. A high proportion of fungi showed a positive association to increasing tree growth. This resulted in higher fungal richness in fast-grown trees both at the trunk scale and across multiple studied trunks. Such patterns were not observed for saproxylic beetles. However, a set of species (both beetles and fungi) preferred slow-grown wood. Moreover, the total number of red-listed species was highest in slow-grown trunks. We conclude that dead wood from slow-grown trees hosts relatively fewer saproxylic species, but a part of these may be vulnerable to production forestry. It implies that slow-grown trees should be a target in nature conservation. However, where slow-grown trees are absent, for instance in forests managed for a high biomass production, increasing the volumes of dead wood from fast-grown trees may support many species.

The diversity of saproxylic beetles’ community from the Natural Reserve Voievodeasa Forest, North-Eastern Romania

Nature reserves harbour considerable richness and diversity of saproxylic organisms since dead wood is preserved in situ, this being also the case of Voivodeasa beech-spruce-fir forest in North-Eastern Romania, the area investigated under the present research. Flight interception traps were employed to capture insects during a vegetation season with the goal to characterize saproxylic Coleoptera community in terms of diversity and several other structural features. Among the captured insects, the majority pertained to obligate saproxylic species (217 species). However, the unexpected high species richness corresponded to an area with modest representation of deadwood due to previous status of commercial forest. The identified beetles were members of different habitat-guilds depending on what type of substrate they colonized: recently dead wood (23%), decomposed dead wood (41%), wood inhabiting fungi (34%) and treehollow detritus (2%). According to their trophic position, the identified saproxylic beetles pertained to the following guilds: xylophagous (40%), mycetophagous (39%), predatory (14%), and species relying on other food resources. The observed richness corresponded to the case of hyperdiverse communities where sampling never leads to the stabilization of species richness under a realistic sampling scheme. The diversity profiles constructed on Shannon, Gini-Simpson, Berger-Parker and evenness indices for the pooled inventory and for separate samples across the vegetation season indicated the aggregated saproxylic community as highly diverse and highly uneven, with rich representation of rare species, dominated by few abundant species. We assembled four bipartite, unweighted, and undirected networks to approach the temporal changes across the sampling period extended over one vegetation season. The topology of beetles’ community and of the three main trophic guilds (xylophagous, mycetophagous and predatory) networks linked to time sequences are characterized by high connectance, high nestedness and modularity, with the exception of the mycetophagous sub-network not displaying significant modularity. Among the identified species, 13% indicate high degree of naturalness of the Voievodeasa forest. 62 of the identified species are included in the Red List of European Saproxylic Beetles of which five are near threatened (Protaetia fieberi, Cucujus cinnaberinus, Crepidophorus mutilatus, Ceruchus chrysomelinus, Prostomis mandibularis), Ischnodes sanguinolentus is vulnerable and Rhysodes sulcatus is an endangered species. During the study, two Coleoptera species, new for Romanian insect fauna were identified: Denticollis interpositus Roubal, 1941 and Hylis procerulus (Mannerheim 1823).