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At the end of 2013, strong wind destroyed spruce stands on large areas of Kościeliska Valley in Tatra Mts. in Poland. In 2015–2017, 304 bark samples were collected from 106 spruces; 25 cm × 25 cm large samples were taken from 2 or 4 sections of infested trees in July/August each year. The infestation density, sex ratio, length of maternal galleries, number of progeny and impact of natural enemies were recorded. The infestation density in individual years was 0.79–0.86 mating chambers per dm2, the average length of maternal gallery (55.2–56.6 mm) did not differ between years, The average number of progeny per female from 3-year pooled data was 18.22, the highest in 2015 (27.4) then collapsed to 15.5–16.8. The gallery systems with 2 females, in which the reproduction success was the highest, dominated (62.6%). The frequency of parasitoids or entomopathogens was very low (2–20% mortality rate in 19 bark samples). Possible reasons of relatively low reproduction success regardless generally favourable breeding conditions and its collapse after first year, such as high infestation density and low survival rate of larvae because of climatic conditions (drought), are discussed. Taking into account the described population features, very intense tree mortality and mechanisms known from the other wind events, further development of the outbreak can be expected in this area.

In 2011-2013, trials on the use of the entomopathogenic fungus Beauveria bassiana against bark beetle (Ips typographus) populations were carried out under open field conditions in Norway spruce stands suffering from an outbreak in the Beskid Żywiecki Mts. in Poland. Modified pheromone traps were deployed to capture and thereafter release fungus-infected bark beetles to the forest environment. Infested spruce trees felled next to the traps remained unaffected by the transmission of the fungus to insect populations. Direct spraying or dusting of lying trap logs and suspended caged rearing bolts did not have any effect on spruce infestation by I. typographus, its reproduction success and development or natural enemies inside the bark. A very small effect on mortality rates of target as well as non-target insects overwintering in the dusted litter was observed. Treated stands, unlike control stands, were indirectly affected by the treatment, evidenced by the reduction of tree mortality due to bark beetle infestation. At present, no recommendations concerning the potential use of the fungus in forest protection can be given. However such an environmentally friendly approach represents a promising future prospect.

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. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down., {"references":["Anderbrant O. 1985. Intraspecific competition affecting parents and offspring in the bark beetle Ips typographus. Oikos, 45, 89–98.\n\nAnderbrant O. 1990. Gallery construction and oviposition of the bark beetle Ips typographus (Coleoptera: Scolytidae) at different breeding densities. Ecological Entomology, 15, 1–8.\n\nAnderbrant O., Schlyter F. 1989. Causes and effects of \nindividual quality in bark beetles. Holarctic Ecology, 12 (4), 488–493.\n\nAtkins M.D. 1975. On factors affecting the size, fat content and behaviour of a scolytid. Zeitschrift für angewandte Entomologie, 78, 209–218.\n\nBotterweg P.F. 1982. Dispersal and flight behaviour of \nthe spruce bark beetle Ips typographusin relation \nto sex, size and fat content. Zeitschrift für angewandte Entomologie, 94, 466–489.\n\nBotterweg P.F. 1983. The effect of attack density on size, \nfat content and emergence of the spruce bark beetle \nIps typographus L. Zeitschrift für angewandte Entomologie, 96, 47–55.\n\nChristiansen E., Waring R.H., Berryman A.A. 1987. Resistance of Conifers to Bark Beetle Attack: Searching for General Relationships. Forest Ecology and Management, 22, 89–106.\n\nDeJong M.C.M., Grijpma P. 1986. Competition between larvae of Ips typographus. Entomologia Experimentalis et Applicata, 41, 121–133.\n\nFaccoli M., Buffo E.2004. Seasonal variability of sex-ratio in Ips typographus(L.) pheromone traps in a multivoltine population in the Southern Alps. Journal of Pest Science, 77, 123–129.\n\nGries G. 1985. On the question of dispersal of the engraver beetle (Ips typographusL.) (in German with English sumary). Zeitschrift für angewandte Entomologie, 99, 12–20.\n\nGrodzki W. 2004. Some reactions of Ips typographus(L.) (Col.: Scolytidae) to changing breeding conditions in a forest decline area in Sudeten Mountains, Poland. Journal of Pest Science, 77, 43–48.\n\nGrodzki W. 2007. The use of pheromone traps for the monitoring of Ips typographus(L.) populations in selected national parks in the Carpathians (in Polish with English sumary). Prace Instytutu Badawczego Leśnictwa, Rozprawy i monografie, 8, 1–127.\n\nGrodzki W. 2010. The decline of Norway spruce Picea abies (L.) Karst. stands in Beskid Śląski and Żywiecki: theoretical concept and reality. Beskydy, 3 (1), 19–26.\n\nGrodzki W., Loch J., Armatys P. 2006. Occurrence of Ips typographus L. in wind-damaged Norway spruce stands of Kudłoń massif in the Gorce National Park (in Polish with English summary). Ochrona Beskidów Zachodnich, 1, 125–137.\n\nGrodzki W., Starzyk J.R., Kosibowicz M., Michalcewicz J., Mączka T. 2007. Effect of wind throwns on the populations of cambiophagous insects and threat to Norway spruce stands in the Tatra National Park. Report from the research done in 2004–2007 within the project 2 P06L 046 27 (in Polish). Instytut Badawczy Leśnictwa.\n\nGrodzki W., Starzyk J.R., Kosibowicz M. 2011. Can the \nfunctional traits in Ips typographus (L.) reflects its \noutbreak tendency? 80–85. Freiburger Forstliche Forschung Berichte, 89, 80–85. \n\nGrodzki W., Starzyk J.R., Kosibowicz M. 2014. Influence of selected stand characteristics on the intensity of bark beetle Ips typographus(L.) occurrence in Beskid Żywiecki (in Polish with English summary). Leśne Prace Badawcze, 2, 159–169.\n\nLobinger G. 1996. Variations in sex ratio during an outbreak of Ips typographus (Coleoptera: Scolytidae) in Southern Bavaria. Anzeiger für Schädlingskunde, Pflanzenschutz, Umweltschutz, 69, 51–53.\n\n\nLukášová K., Holuša J., Grucmanová Š. 2012. Reproductive performance and natural antagonists of univoltine population of Ips typographus (Coleoptera, Curculionidae, Scolytinae) at epidemic level: A study from Šumava Mountains, Central Europe. Beskydy, 5 (2), 153–162.\n\nMatoušek P., Modlinger R., Holuša J., Turčáni M. 2012. Number of eggs laid by the spruce bark beetle Ips typographus (L.) (Coleoptera: Curculionidae: Scolytinae) on trap trees: influence of selected factors (in Czech with English summary). Zprávy Lesnického Výzkumu, 57 (2), 126–132.\n\nNetherer S., Nopp-Mayr U. 2005. Predisposition assessment systems (PAS) as supportive tools in forest management – rating of site and stand-related hazards of bark beetle infestation in the High Tatra Mountains as an example for system application and verification. Forest Ecology and Management, 207, 99–107.\n\nSallé A., Baylac M., Lieutier F., 2005. Size and shape \nchanges of Ips typographus L. (Coleoptera, Scolytinae) in relation to population level. Agricultural and Forest Entomology, 7, 297–306.\n\nSchlyter F., Zhang Q.-H. 1995. Testing avian polygyny \nhypotheses in insects: harem size distribution and female egg gallery spacing in Ipsbark beetles. Oikos, 76, 57–69.\n\nSchopf R., Köhler U. 1995. Investigations on the population dynamics of spruce bark beetle in Bayerischer Wald National Park. In: Biberlriether, H. et al.: 25 years towards natural forest (in German). Passavia Druckerei GmbH, Passau, 88–109.\n\nStarzyk J.R., Graboń K., Hałdaś E. 2000. Cambio- and \nxylophagous insects in spruce (Picea abies (L.) \nKarst.) stands of the Upper San River Valley in the \nBieszczady Mountain National Park (Eastern Carpathians). Scientific Papers of the Agricultural Uni-versity of Cracow, Forestry, 29, 57–73.\n\nStatSoft, Inc. 2009. STATISTICA for Windows [Computer program manual]. Tulsa, OK: StatSoft, Inc., http://www.statsoft.com\n\nWeslien J. 1994. Interactions within and between species \nat different densities of the bark beetle Ips typographus and its predator Thanasimus formicarius. Entomologia Experimentalis et Applicata, 71, 133–143."]}