A review of saproxylic beetle intra- and interspecific genetics: current state of the knowledge and perspectives

Forests are important habitats that harbor high biodiversity and have great economic value to humans. These ecosystems depend on saproxylic organisms, which play a crucial role in the decomposition of the main substrate of forests – wood. The highly important group of saproxylic organisms are beetles, with numerous species that are either of conservation concern (rare and threatened) or have economic value (“pests”). This review summarizes what is known about intra- and interspecific genetic information on species or populations of saproxylic beetles. A search of the literature yielded 110 articles published in 57 journals. The majority of molecular research has focused on “pests” (82 articles on 59 species), with fewer studies of the “non-pest” beetles (28 articles on 40 species, including 10 relicts of primeval forests). Most studies concerned Palearctic and Nearctic taxa, with only a few articles on beetles from (sub)tropical forests. Members of 11 families, 38 genera and 99 species were the subject of molecular studies. The majority of studies (71%) were conducted on beetles associated with conifers. Genetic metrics were found to have different overall values in “pests” and the “non-pest” species. Analyzes resulted in identification of units or either conservation (15 cases) or taxonomic (33) value, the discovery of hybridization (4), invasion routes, and common phylogeographic patterns with the localization of glacial refugial areas. This article is the first comprehensive summary of what is known about the history, present-day diversity, and relationships of highly important group of saproxylic beetles based on molecular studies. “Pests” found to be much wider studied than threatened taxa. A list of species that should be the subject of future molecular studies was provided along with a rationale. Finally, methodological and objective deficiencies in previous studies were characterized.