Flight behaviour of Ips typographus L. (Col., Scolytidae) in an environment without pheromones

Abstract

-A mark-recapture experiment with Ips typographus (Coleoptera: Scolytidae) was carried out on a 1-ha experimental plot in a healthy spruce stand in Belgium. Recapture of the released beetles was carried out using 96 unbaited standing live trap trees distributed homogeneously over the experimental plot. Less than 0.3 % of the marked beetles were recaptured during three replicates of the experiment. When a pheromone lure was added to one of the trap trees in a fourth replicate, the recapture rate rose to nearly 6 %. Implications for the beetles' dispersal are discussed. Moreover, the take-off rates were found to be strongly correlated to weather conditions at emergence: correlations between take-off percentages and the number of sunshine hours per day (r = 0.75), the average daytime relative humidity (r = -0.75) and the cloud cover index at noon (r = -0.63) were found to be highly significant (P <

Quantifying spatio-temporal dispersion of bark beetle infestations in epidemic and non-epidemic conditions

“…in Byers, 1999;Franklin and Grégoire, 1999;Turchin and Thoeny, 1993) practically impede a coherent interpolation from trap catches to a continuous spatial distribution. Passive traps placed three-dimensionally would be the method of choice, but they usually do not catch sufficient numbers of individuals at farther distances (Franklin and Grégoire, 1999). Thus, it is almost impossible to quantify beetle dispersal in a direct and unbiased way in the field.…”

“…For example, long-distance dispersers can colonize trees very close to other sources (e.g. attracted by aggregation pheromones there, Franklin and Grégoire, 1999). Genetic tests might be an option for finally identifying those long-distance dispersers migrating from distant populations, although genetic differentiation of I. typographus seems difficult at regional scale (Gugerli et al, 2008).…”

“…Duelli et al, 1997;Zolubas and Byers, 1995;Zumr, 1992; for Dendroctonus frontalis e.g. Turchin and Thoeny, 1993) or passive traps (for I. typographus Franklin and Grégoire, 1999). The models show dispersal curves in the form of decreasing power or exponential functions, i.e.…”

Integrating mechanistic disturbance models and stand dynamics of Norway spruce

“…After the beetles have developed to adults, they fly and attack trees in order to reproduce. Bark beetles can travel long distances and in pheromone-free environments only 1% remains within one hectare from the mother tree (Franklin and Grégoire, 1999).…”

The proposal of biotic hazard zones in selected spruce dominated regions in Slovakia

“…Spatial patterns of tree mortality and tree infestation by biotic agents have been studied rarely (Franklin, Grégoire 1999;Otto, Schreiber 2001;Taylor, MacLean 2007). Such a study allows for a profound understanding of their ecology (Grodzki 2004;), proposing forest protection measures (Capecki 1981;Turčáni, Hlásny 2007) and prioritization of forest conversions (Kulla, Hlásny 2009).…”