DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 9-10/2018 str. 25     <-- 25 -->        PDF

insects were assessed visually. Callow beetles, larvae and pupae were considered dead if they showed no sign of movement at room temperature, or were deformed (Faccoli, 2002).
The reproductive success is defined as a number of daughters per mother beetle (♀/♀), and was calculated as:

assuming that one exit hole represents one emerged adult beetle (Schlyter et al., 1984; Komonen et al., 2011), and a balanced sex ratio – 0.5 (Annila, 1971).
Number of:
a – exit holes
b – young living adults in the bark
c – maternal galleries
The measured parameters (reproductive success, total production, gallery number per mating chamber, predator larvae abundance) were first processed in Microsoft® Office 2007, and then compared in Statsoft® Statistica 8 by means of non-parametric Kruskal-Wallis test. The mortality per m2 in each development stage were calculated in Microsoft® Office 2007. The Sperman Rank correlation between the predator abundance and the bark beetle attack density were calculated in Statsoft® Statistica 8.
RESULTS
Rezultati
In total, 55 sections were analysed (table 1.). The number of analysed samples (sections) differed between trees due to the decomposition of bark in top sections or no visible sight of I. typographus colonization. Top sections with thinner bark were not analysed because dominant bark beetle species was Pityogenes chalcographus (Linnaeus) (Coleoptera: Curculionidae: Ipini). Because of difference in the number of samples taken from a single tree, the non-parametric Kruskal-Wallis test was used in the data analysis.