<abstract xmlns="http://www.w3.org/1999/xhtml"> In 2010-2012, investigations on Ips typographus populations were carried out in Norway spruce stands recently affected by bark beetle outbreak in the Beskid Żywiecki Mts. in Poland. The aim of the study was to test the usefulness of several traits describing I. typographus populations for evaluation of their actual outbreak tendency. Infestation density, sex ratio, gallery length, progeny number and beetle length were used as the traits. Trait variability was analyzed in relation to infested tree mortality in the current year of observation and outbreak tendency defined by the comparison of data on tree mortality in the current year and that in the year before. The highest infestation density was found in the stands representing the highest tree mortality in the current year and in those characterized by decreasing outbreak tendency. The gallery system with 2 maternal galleries dominated. The sex ratio of attacking beetles inclined towards females (63.8%) and remained stable during 3 years of observations; the highest percentage of females was found in locations being in stabilization/latency outbreak phase. The length of maternal galleries was somewhat negatively affected by infestation density and positively correlated with the number of progeny in the gallery. The average beetle length was 4.800 mm (± 0.293), ranging between 3.718 and 5.817 mm and being the highest in the uppermost class of tree mortality recorded in the current year of observation. The shortest beetles were collected in the stands with increasing outbreak tendency, and slightly longer - in the stands with outbreak stable and decreasing tendencies. None of the traits tested can be selected as a direct indicator for prediction of outbreak tendency in I. typographus populations. Possible reasons of variability in the analyzed traits are discussed. The traits indicate that I. typographus in the study area represent very high reproductive potential, thus the risk of repeated outbreak is very high</abstract>

In 2010-2012, investigations on Ips typographus populations were carried out in Norway spruce stands recently affected by bark beetle outbreak in the Beskid Żywiecki Mts. in Poland. The aim of the study was to test the usefulness of several traits describing I. typographus populations for evaluation of their actual outbreak tendency. Infestation density, sex ratio, gallery length, progeny number and beetle length were used as the traits. Trait variability was analyzed in relation to infested tree mortality in the current year of observation and outbreak tendency defined by the comparison of data on tree mortality in the current year and that in the year before. The highest infestation density was found in the stands representing the highest tree mortality in the current year and in those characterized by decreasing outbreak tendency. The gallery system with 2 maternal galleries dominated. The sex ratio of attacking beetles inclined towards females (63.8%) and remained stable during 3 years of observations; the highest percentage of females was found in locations being in stabilization/latency outbreak phase. The length of maternal galleries was somewhat negatively affected by infestation density and positively correlated with the number of progeny in the gallery. The average beetle length was 4.800 mm (± 0.293), ranging between 3.718 and 5.817 mm and being the highest in the uppermost class of tree mortality recorded in the current year of observation. The shortest beetles were collected in the stands with increasing outbreak tendency, and slightly longer - in the stands with outbreak stable and decreasing tendencies. None of the traits tested can be selected as a direct indicator for prediction of outbreak tendency in I. typographus populations. Possible reasons of variability in the analyzed traits are discussed. The traits indicate that I. typographus in the study area represent very high reproductive potential, thus the risk of repeated outbreak is very high

Variability of Selected Traits of Ips Typographus (L.) (Col.: Scolytinae) Populations In Beskid Żwiecki (Western Carpathians, Poland) Region Affected By Bark Beetle Outbreak

Forest Research Institute, Department of Mountain Forestry, Fredry 39, 30-605 Kraków, Poland

University of Agriculture, Chair of Forest Protection, Forest Entomology and Forest Climatology, Kraków, Poland

Folia Forestalia Polonica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

In 2010-2012, investigations on Ips typographus populations were carried out in Norway spruce stands recently affected by bark beetle outbreak in the Beskid...

Variability of Selected Traits of Ips Typographus (L.) (Col.: Scolytinae) Populations In Beskid Żwiecki (Western Carpathians, Poland) Region Affected By Bark Beetle Outbreak

Published Online: Sep 25, 2014

Page range: 79 - 92

Received: Feb 05, 2014

Accepted: Mar 17, 2014

DOI: https://doi.org/10.2478/ffp-2014-0008

Keywords
bark beetles, galleries, progeny, sex ratio, body length, population dynamics

© 2014

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Variability of Selected Traits of Ips Typographus (L.) (Col.: Scolytinae) Populations In Beskid Żwiecki (Western Carpathians, Poland) Region Affected By Bark Beetle Outbreak

Published Online: Sep 25, 2014

Page range: 79 - 92

Received: Feb 05, 2014

Accepted: Mar 17, 2014

DOI: https://doi.org/10.2478/ffp-2014-0008

Keywordsbark beetles, galleries, progeny, sex ratio, body length, population dynamics

© 2014

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
bark beetles, galleries, progeny, sex ratio, body length, population dynamics