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Title:Osmerozobi smrekov lubadar (Ips typographus (L.)) in z njim povezana subkortikalna entomofavna navadne smreke (Picea abies (L.) Karst.) v altimontanskem pasu Slovenije
Authors:ID Podlesnik, Jan (Author)
ID Jurc, Maja (Mentor) More about this mentor... New window
ID Devetak, Dušan (Comentor)
Files:.pdf EDOK_Podlesnik_Jan_2016.pdf (6,07 MB)
MD5: 4F537386DB231B945719648E001499AE
 
Language:Slovenian
Work type:Dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FNM - Faculty of Natural Sciences and Mathematics
Abstract:Osmerozobi smrekov lubadar, Ips typographus, je ekološko in ekonomsko pomembna vrsta v evropskih gozdovih. Z ekološkega vidika je pomemben, ker predstavlja prvo stopnjo v dekompoziciji oslabele ali bolne smreke. Kot drevesni parazit pa povzroča veliko ekonomsko škodo v smrekovih gozdovih. Na njegov razvoj vplivajo abiotski dejavniki, kot je npr. temperatura, in tudi biotski dejavniki, kot je debelina skorje, predvsem pa lubadarjevi plenilci in parazitoidi. Raziskava je bila izvedena v altimontanskem pasu Slovenije (Pohorje), kjer je v gozdovih precej smreke in kjer so potencialna območja za pojavljanje množičnih napadov I. typographus. Ugotavljali smo vpliv temperature na naselitev podrte smreke in hitrost razvoja vrste I. typographus. Poleg tega smo analizirali združbo, ki naseljuje skorjo sveže podrte smreke, kar je posledica predhodne naselitve osmerozobega smrekovega lubadarja. Preverjali smo, kateri so glavni plenilci in parazitoidi vrste I. typographus. Preverjali smo vpliv nadmorske višine (temperature), tipa gozda in leta vzorčenja na gostoto naselitve vzorčnih dreves s podlubniki ter njihovimi plenilci in parazitoidi, kot tudi na diverziteto omenjenih skupin. Poleg tega smo ugotavljali vpliv naravnih sovražnikov na populacijo vrste I. typographus. Povprečne dnevne temperature v obdobju od sredine maja do konca avgusta se na naših lokacijah gibljejo med 13,1 in 15,5 °C. Debelina skorje vzorcev je bila med 4 in 7 mm. Ugotovili smo, da se temperatura v mikrohabitatu, ki ga naseljuje preiskovana vrsta, od temperature zraka v okolici razlikuje za do 3 °C. Tudi med mikrolokacijami na enem drevesu obstajajo razlike do 2,3 °C, ki so posledica različne ekspozicije in osenčenosti različnih delov debla. Osmerozobi smrekov lubadar izbira dele skorje z višjo temperaturo in se v takšnih mikroklimatskih razmerah tudi hitreje razvija (pozitivna korelacija med temperaturo in številom odraslih I. typographus). Povprečna vsota efektivnih temperatur, ki jo potrebuje za zaključek generacije, znaša 661 stopinj dni. Ugotovili smo tudi, da število osebkov I. typographus pada z naraščanjem debeline skorje, kar pa ni bilo statistično značilno. Na lokaciji Kladje (nadmorska višina 1304 m) je v letu raziskave osmerozobi smrekov lubadar razvil eno generacijo. Razvoj je trajal od 60 do 86 dni (povprečno 73 dni). Našli smo 62 vrst, ki naseljujejo podrto smreko v prvem letu naseljevanja. Od tega je bilo 9 vrst podlubnikov, 12 vrst parazitoidov in 27 vrst plenilcev podlubnikov. Najštevilnejša vrsta je bila I. typographus s 5216 osebki. Identificirali smo plenilski in parazitoidni kompleks omenjene vrste. Najpomembnejši plenilci so Thanasimus formicarius (Coleoptera) (83 osebkov) in vrste iz rodov Medetera (88 osebkov) in Lonchaea (170 osebkov) (Diptera). Daleč najpogostejši parazitoid je bil s 1072 osebki Roptrocerus xylophagorum (Hymenoptera). Ugotovili smo še, da se je število plenilcev in parazitoidov v drugem letu raziskave povečalo. Pokazalo se je tudi, da je diverziteta parazitoidov nižja na višjih nadmorskih višinah in v smrekovi monokulturi. I. typographus izletava iz skorje sočasno z najpogostejšim parazitoidom R. xylophagorum, medetem ko plenilci izletijo z enotedenskim zamikom. Plenilci in parazitoidi pomembno vplivajo na populacijo I. typographus, saj jo v prvem letu raziskave zmanjšajo za 40 %, v drugem pa celo za 68 %. 50-odstotno k smrtnosti prispevajo plenilci, 12-odstotno pa parazitoidi.
Keywords:podlubniki, Scolytinae, Ips typographus, temperatura, plenilci, Thanasimus formicarius, parazitoidi, Hymenoptera
Place of publishing:[Maribor
Publisher:J. Podlesnik]
Year of publishing:2016
PID:20.500.12556/DKUM-59437 New window
UDC:630*45:595.768.2(497.4Pohorje)(043.3)
COBISS.SI-ID:286867712 New window
NUK URN:URN:SI:UM:DK:VMLXMXHK
Publication date in DKUM:17.10.2016
Views:2898
Downloads:326
Metadata:XML DC-XML DC-RDF
Categories:FNM
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Secondary language

Language:English
Title:Ips typographus (L.) and associated subcortical entomofauna of Norway spruce in the altimontane belt of Slovenia
Abstract:Ips typographus (European spruce bark beetle) is economically and ecologically a very important species in European forests. As a tree parasite, it causes significant damage to spruce forests in Europe. From the ecological point of view, it is involved in the first step of the decomposition of a weakened or diseased spruce tree. Its development is influenced by abiotic factors, such as temperature, as well as biotic factors, e.g. bark thickness and particularly its predators and parasitoids. The survey was conducted in the altimontane elevation belt of Slovenia (Pohorje), where there are a lot of spruce forests, which is why the area is a potential target for mass attacks of I. typographus. In our study we tried to determine the effects of temperature on the colonization of a felled spruce tree and on the development time of I. typographus. We also analyzed the saproxylic community associated with the European spruce bark beetle. We tried to establish the parasitoid and predatory complex of the discussed species. We also examined the effects of altitude (temperature) and type of forest and the impact of sampling year on the abundance of bark beetles, their predators and parasitoids, as well as the diversity of the mentioned groups of insects. In addition, the effects of natural enemies on the population of I. typographus were assessed. Average daily temperatures of our research locations from mid-May to late August were between 13.1 and 15.5°C. Bark thickness of our samples was between 4 and 7 mm. We had established that the temperature of the microhabitat inhabited by I. typographus differs from the air temperature in the proximity of the tree by as much as 3°C. Also, temperatures of microlocations on the same trunk were quite different because of their orientation and exposure to direct solar irradiation. The differences were as high as 2.3°C. The European spruce bark beetle prefers to colonize those parts of the trunk that have higher under-bark temperatures, and these were also the locations where the brood developed more rapidly. We found a positive correlation between temperatures and the number of adult specimens of I. typographus. The effective temperature sums needed for development of one generations were 661 degree days. The number of I. typographus adults decreased with increasing bark thickness, however, this was not statistically significant. In Kladje (1304 m altitude), I. typographus developed one generation in the year of our research. The time needed for development of this generation was between 60 and 86 days (73 days on average). In the three years of our research, we found 62 species that inhabit the spruce tree in the first year of colonization. We found 9 species of bark beetles, 12 species of parasitoids and 27 species of predators of bark beetles. The most abundant species was I. typographus with 5216 individuals. The predatory and parasitoid complex of this species was identified. The most important predatory species were Thanasimus formicarius (Coleoptera) (83 individuals) and species of Medetera (88 individuals) and Lonchaea (Diptera) (170 individuals). By far the most important parasitoid was Roptrocerus xylophagorum (Hymenoptera) with 1072 individuals. We found out that the number of predators and parasitoids increased in the second year of our study. In addition, we observed lower parasitoid diversity at highest altitudes and in a spruce monoculture. I. typographus emerges from the bark at roughly the same time as its most common parasitoid R. xylophagorum, however, predators emerge with one-week delay. Predators and parasitoids had an important impact on population of I. typographus, as it decreased by 40% in the first year and by as much as 68% in the second year. The predators caused 50% of I. typographus’ mortality, while parasitoids only caused 12%.
Keywords:Bark beetles, Scolytinae, Ips typographus, temperature, predators, Thanasimus formicarius, parasitoids, Hymenoptera


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