Phylogeography and postglacial colonization routes of Ips typographus L. (Coleoptera, Scolytidae)

Abstract

Ips typographus populations were analysed by enzyme electrophoresis and by sequence analysis in order to quantify the degree of population differentiation. Enzyme electrophoresis showed a high gene flow among all European populations. Analysis of single loci showed that aspartate aminotransferase‐2 (Aat‐2) clustered the Scandinavian populations apart from the other populations whereas other enzyme loci showed no significant pattern. Analysis of mitochondrial DNA revealed eight haplotypes. The populations from Italy, Croatia and Belgium were the most polymorphic. Two haplotypes (I and II) were found in the majority of Central European populations. In the northern populations only one haplotype (I) was found. The Russian and Lithuanian populations had a particular haplotype (IV) that was not found in any of the other populations. In view of these data it is suggested that the population structure of I. typographus has been influenced by events which took place during and after the last ice age. Populations were forced into refugial areas in the south and in the area north of Moscow along with the host tree, Picea abies. P. abies had four refugial areas: the Apennine Alps, the Dinaric Alps, the Carpathian Alps and Kostroma, an area north of Moscow. With amelioration of the temperature, beetles spread after P. abies. According to the data presented here, I. typographus migrated from the Apennine and/or Dinaric Alps to the north. Whilst there is evidence for high gene flow among populations, bottleneck effects can still be detected in the north and also in the east. Beetles from the refugial area north of Moscow did not spread to Scandinavia or to the west like the host tree.

Genetic structure and phylogeography of pine shoot beetle populations (Tomicus destruens and T. piniperda, Coleoptera Scolytidae) in Italy

“…Another possible explanation of the high number of isolated haplotypes (8 out of 11) can be found in the role played by the Alps during the last glaciation, as they were a refuge area for many European insect populations forced to move southward, looking for more suitable climatic conditions [14]. This migration had therefore increased the genetic pool of T. piniperda in Italy, as it genetic structure of Tomicus in Italy 367 has been observed also for the spruce bark beetle Ips typographus, which also has a large Palaearctic diffusion [31]. Similar considerations were reported by Ritzerow et al [24], who suggest the high polymorphism of T. piniperda as due to the existence of several distinct refugial areas during the last ice age.…”

“…The central geographic position of Italy in the Mediterranean could be important for understanding the genetic structure of Tomicus populations occurring in southern Europe. For example, during the last glaciation Italian pine forests could have been a refuge area for Tomicus populations, as suggested for other bark beetle species [31]. In addition, we want to test the possible sympatry of T. destruens and T. piniperda in Italian transition areas between continental and Mediterranean pine forests.…”

Complex postglacial history of the temperate bark beetle Tomicus piniperda L. (Coleoptera, Scolytinae)

“…Genetic data for beetles sampled from eastern populations of P. sylvestris or from Asia Minor could help to distinguish between different hypotheses. It is interesting that the occurrence of northern glacial refugia from either Central or Eastern Europe was suggested for the spruce Picea abies and two of its associated bark beetles Ips typographus and Pityogenes chalcographus (Lagercrantz and Ryman, 1990;Stauffer et al, 1999;Avtzis et al, 2008) that are ecologically similar to T. piniperda. Most of the other sampling sites are characterized by the occurrence of one of the two main haplotypes, 1A and 1B, and the whole group of populations bears signs of fairly recent population expansion, which is expected during the interglacial northern colonization of suitable habitats, after the range contraction imposed by the glacial maximum (Slatkin and Hudson, 1991;Avise, 2000).…”

“…In that case, the phylogeographic pattern of the dependent species can be influenced by that of its partner, and a certain level of similarity may be highlighted (see for instance Burban et al, 1999;Burban and Petit, 2003). However, this is not always the case and the genetic structure of insects does not necessarily reflect that of its host (Stauffer et al, 1999;Sallé et al, 2007).…”

Genetic structure of the forest pest Hylobius abietis on conifer plantations at different spatial scales in Europe

“…For example, longhorn beetles developing on decaying host plants exhibit higher dispersal ability than taxonomically close species developing on living host plants (see the review on Cerambycid beetles by Hanks, 1999). High dispersal ability was also shown by genetic analysis in Ips typographus, a bark beetle attacking weakened trees (Stauffer et al, 1999). Thus, habitat persistence may influence gene flow through its effect on the evolution of dispersal behaviour (Roderick, 1996).…”