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

Abstract

The distribution of genetic variation within and among 20 European sites infested by the large pine weevil, Hylobius abietis, was analysed using dominant amplified fragment length polymorphism markers. Analysis of molecular variance was performed at the European, regional and local scales. Most of the genetic variability was found within rather than among populations and the global fixation index averaged over loci was low (0.07). We found no evidence of genetic drift, even in relatively isolated sites. This genetic pattern tends to confirm the high dispersal ability of the weevil and the influence of human-mediated expansion of its range through conifer plantations across Europe since the 19th century. Assignment tests demonstrated that the regional forest is a pertinent geographic scale for defining populations in the large pine weevil. Testing the potential influence of the larval host-plant identity (Scot Pine vs Norway Spruce) on the genetic structure revealed a weak but significant effect in two of the three regions tested (in Ardè che and in Limousin but not in Finland). One locus varied with host-plant use in the two French regions, indicating a potential role in host-plant adaptation. However, host-race formation is not observed in H. abietis; we discuss this result in the light of our current knowledge of this insect's biology. Altogether, this study shows that the use of different host plants for development does not constitute a strong barrier to gene flow for H. abietis and confirms the high dispersal ability of this forest pest.

Genetic diversity of the xerothermic weevils Polydrusus inustus and Centricnemus leucogrammus (Coleoptera: Curculionidae) in central Europe

“…Human-mediated dispersal may also promote the dispersal of P. inustus (Mazur, 1994). A similar lack of genetic differences between populations was found in many highly mobile (often flying) species of weevils and bark beetles, which inhabit the coniferous forests of Eurasia (Stauffer et al, 1999;Faccoli et al, 2005;Conord et al, 2006;Lakatos et al, 2007). These species are tree pests and spread only a few thousand years ago after climate warming.…”

Flying between Sky Islands: The Effect of Naturally Fragmented Habitat on Butterfly Population Structure

“…So, we decided to use the Amplified Fragment Length Polymorphisms (AFLPs) technique instead. The AFLP protocol is known to be sensitive to contamination, especially from microbial DNA, which is abundant in the digestive system of the insect [20]. Hence, care was taken to use only two legs for the extractions.…”

Genetic structure of populations of Pissodes castaneus (De Geer) (Coleoptera, Curculionidae) using amplified fragment length polymorphism

“…They found an allelic fixation index of 0.879, with a high level of differentiation among populations. Another weevil species, Hylobius abietis L., studied by Conord et al (2006) using also amplified fragment length polymorphism, showed low level of al- Table III. Genetic identity (above diagonal) and Nei's genetic distance (Nei 1972) (below diagonal) for Pissodes castaneus populations, considering samples from 20 localities determined by PCR-AFLP.…”

“…The relatively high genetic diversity among populations of P. castaneus indicates a diverse gene pool in the regions studied. As a result, the response of different populations to control strategies, chemical, biological or silvicultural, may vary according to the heterogeneity of the populations (Conord et al 2006;Planter 2007).…”