Host tree and insect genetic diversity on the borderline of natural distribution: a case study of Picea abies and Pityogenes chalcographus (Coleoptera, Scolytinae) in Greece

Abstract

Picea abies (L.) Karst. and Pityogenes chalcographus constitute a commonly observed host tree-insect association in Eurasia, with the natural distribution of the bark beetle overlapping that of Norway spruce. The southernmost borderline of their distributions occurs in the Elatia forest (Mt. Rodopi, Greece), where these interacting organisms may experience severe conditions due to the effects of climate change. In order to assess the dynamics of this host tree-insect association, the genetic diversity of both organisms was studied. In contrast to previous studies, the assessment of molecular diversity was based on the same mitochondrial gene (Cytochrome Oxidase One) sequence for both host and pest. This analysis revealed a remarkably higher genetic diversity of P. chalcographus compared to that of P. abies, something that renders the insect capable not only of adapting to novel environmental conditions, but even of shifting to other host species. On the contrary, P. abies presented a narrow genetic base, a potential drawback at the southern-most region of the species natural distribution. Synthesizing the preliminary outcome for both organisms, it appears that P. chalcographus exhibits an evolutionary advantage over P. abies, something that should be considered when planning conservation strategies for the relict forest of Elatia.

Assessment of Genetic Diversity and Population Genetic Structure of Norway Spruce (Picea abies (L.) Karsten) at Its Southern Lineage in Europe. Implications for Conservation of Forest Genetic Resources

“…For example, Keren et al [9] noticed that warm and dry summers are frequently followed by bark beetle outbreaks, which in turn cause a notable spruce decline. Indeed, studying the parallel genetic diversity of Norway spruce and Pityogenes chalcographus at the southernmost borderline of their distribution range, Avtzis and Aravanopoulos [10] found a significantly higher genetic diversity for the same gene in spruce bark beetle compared to the host, which might, in turn, provide a better evolutionary potential for adaptation of the insect to altered environmental conditions. Furthermore, Stojanović et al [11] reported that significant change of Norway spruce bioclimatic niche in Serbia might be expected by the end of 21st century.…”

Utility of the Mitochondrial Genome in Plant Taxonomic Studies

“…Universal primers were defined in conserved regions (exons) and were used to amplify mtDNA regions with conserved microsynteny. Polymorphism in amplified fragment has been revealed with various methods: PCR-RFLP (Boonruangrod et al, 2008;Godbout et al, 2005;San Jose-Maldia et al, 2009;Moriguchi et al, 2009;Naydenov et al, 2007), RFLP-SSR (Burban and Petit, 2003;Godbout et al, 2005;Jaramillo-Correa et al, 2003), mtDNA-SSR (Hosaka and Sanetomo, 2009), the variable number of tandem repeats (VNTR) in minisatelite regions (Bastien et al, 2003;Fievet et al, 2007;Honma et al, 2011;Yoshida et al, 2012), and finally in DNA sequences (Avtzis and Aravanopoulos, 2011;Eckert et al, 2008;Edwards et al, 2005;Goodall-Copestake et al, 2010;Gugger et al, 2011). The choice of the candidate loci was limited and was depending on the taxonomic level addressed by the phylogenetic study.…”