20.500.12556/DKUM-93627 Razvoj novih kompleksnih interakcij med tujerodnimi vrstami hroščev in rastlin: plenilstvo, facilitacija in kompeticija doktorska disertacija The formation of new complex interactions between alien species of beetles and plants: predation, facilitation and competition Ekosisteme definirajo organizmi in okolje ter interakcije med njimi. Obsežne spremembe v ekosistemih povečajo njihovo dovzetnost za naselitev tujerodnih vrst. Nove vrste v ekosistemu vzpostavijo nove, včasih tudi nepredvidljive interakcije z obstoječimi ali drugimi tujerodnimi vrstami. Tujerodne vrste so eden od glavnih vzrokov za upadanje biodiverzitete, zato je razumevanje njihovih interakcij z drugimi organizmi ključno za njihovo upravljanje. V raziskavi obravnavamo več vidikov nove interakcije med okrasno drevesno vrsto trnato gledičevko (Gleditsia triacanthos) in dvema azijskima vrstama hroščev semenarjev, Megabruchidius dorsalis in M. tonkineus. Obe vrsti hroščev se na svojem naravnem območju razširjenosti razvijata v semenih azijskih vrst gledičevk, po naselitvi v Evropo pa sta preskočili na nov vir hrane, in sicer sorodno severnoameriško trnato gledičevko. Trnata gledičevka se je v Evropi razširila izven zasajenih območij in je lokalno invazivna. Ima semena s fizično dormanco, kar pomeni, da kalijo šele po fizični poškodbi semenske lupine. V Evropi se je med njo in omenjenima hroščema semenarjema vzpostavila nepredvidljiva interakcija, saj gostitelj in oba plenilca izvirajo iz različnih kontinentov. S serijo poskusov kalitve smo ugotovili, da napadena semena kalijo bolje kot intaktna, predvsem pa, da kalijo bolj sporadično kot mehansko skarificirana semena. Luknja, ki jo ličinka prevrta v seme, poškoduje semensko lupino ravno toliko, da ob primernih okoljskih razmerah facilitira kalitev. Nadalje smo v Mariboru in okolici med letoma 2019 in 2024 zabeležili 59 lokacij s trnato gledičevko, od tega smo na 30 lokacijah zabeležili prosto rastoča drevesa. Plodeča drevesa smo zabeležili na 30 lokacijah in od tega smo na 21 lokacijah pod materinskimi drevesi opazili številne kalice. Prosto rastoča drevesa so se pojavljala na odprtih zapuščenih površinah, na gozdnem robu, v mejicah, živih mejah, ob ograjah in ob drevesih drugih vrst. V povezavi s pojavljanjem trnate gledičevke v mestnem okolju smo raziskovali vlogo živih mej kot habitatov za uspevanje prosto rastočih lesnatih vrst. V živih mejah smo popisali 69 taksonov lesnatih vrst, od tega 62 % tujerodnih. Večjo vrstno pestrost smo zabeležili v listopadnih živih mejah v primerjavi z zimzelenimi. Del raziskave smo namenili tudi raziskovanju razširjenosti obeh vrst hroščev semenarjev. Prisotnost M. dorsalis smo potrdili na 33 lokacijah v Sloveniji, treh lokacijah na Hrvaškem, dveh lokacijah v Črni gori in na eni lokaciji v Bosni in Hercegovini ter eni v Albaniji. Prisotnost M. tonkineus smo potrdili na eni lokaciji v Črni gori. S pregledom literature smo ugotovili, da se obe vrsti v Evropi širita. Z laboratorijskim poskusom smo raziskovali vpliv kompeticije na reproduktivni uspeh hroščev. Megabruchidius tonkineus je imel pri vseh pogojih boljši reproduktivni uspeh kot M. dorsalis. Pri interspecifični kompeticiji se je reproduktivni uspeh bolj poslabšal pri M. tonkineus v primerjavi z intraspecifično kompeticijo, vendar je bil še vedno boljši kot pri M. dorsalis. Večinoma se je iz vsakega semena pojavil en odrasel hrošč, ne glede na število ličink, ki so napadle seme. Raziskava poudarja pomen razumevanja novih interakcij med tujerodnimi vrstami za ocenjevanje njihovega invazivnega potenciala in spremljanje vplivov na ekosisteme. Ecosystems are defined by interactions between organisms, interactions between organisms and the environment, and by the environment itself. Large-scale changes in ecosystems increase their susceptibility to colonization by alien species. New species in the ecosystem lead to new, sometimes unpredictable interactions with native or alien species. Since alien species are a major cause of biodiversity loss, understanding their interaction with other organisms is key to conservation management. In this study, we investigate aspects of a novel interaction between an ornamental tree species, the honey locust (Gleditsia triacanthos), and two Asian species of seed beetles: Megabruchidius dorsalis and M. tonkineus. Both beetle species develop in the seeds of the Asian Gleditsia species in their natural range. However, when they colonized Europe, the beetles switched to a new food source: the related North American honey locust. The honey locust has escaped from planted areas in Europe and is locally invasive. Its seeds are physically dormant, meaning that they germinate only when the seed coat is physically damaged. In Europe, an unpredictable interaction has developed between the honey locust and the seed beetles, since the host and the two predators originate from different continents. In a series of germination experiments, we have found that infested seeds germinate better than intact seeds and, above all, germinate more sporadically than mechanically scarified seeds. The hole where the larva bores into the seed damages the seed coat just enough to allow the seed to germinate under suitable environmental conditions. Such an interaction goes beyond predation and includes elements of facilitation. Between 2019 and 2024, we recorded 59 honey locust sites in Maribor and its surroundings, 30 of which had spontaneous trees. Trees with pods were recorded at 30 sites, and of these, numerous seedlings were observed under the mother trees at 21 sites. Spontaneous trees occurred in open abandoned areas, forest edges, in hedgerows and urban hedges, along fences, and near trees of other species. In connection with the occurrence of the honey locust in urban areas, we investigated the role of urban hedges as a habitat for the spontaneous occurrence of woody species. We recorded 69 taxa of woody species, 62% of which were non-native. Greater species diversity was found in deciduous hedges than in evergreen hedges. Part of the research was dedicated to investigating the distribution of the two species of seed beetle. The presence of M. dorsalis was confirmed at 33 sites in Slovenia, three sites in Croatia, two sites in Montenegro, and one site each in Bosnia and Herzegovina and Albania. The presence of M. tonkineus was confirmed at one site in Montenegro. A literature review revealed that both species are spreading in Europe. We analysed the effects of competition on the reproductive success of the beetles in a laboratory experiment. Megabruchidius tonkineus had better reproductive success than M. dorsalis under all conditions. Under interspecific competition, the reproductive success of M. tonkineus decreased more noticeably, but was still better than that of M. dorsalis. The hatching success of the beetles was high, with usually one adult beetle hatching from each seed, regardless of the number of larvae infesting the seed. The study emphasises the importance of understanding novel interactions between alien species to assess their invasive potential and monitor their impact on ecosystems. kalitev fizična dormanca žive meje urbano okolje razširjenost vrst reproduktivni uspeh germination physical dormancy urban hedges urban area species distribution reproductive success true true false [E. Horvat] Slovenski jezik Angleški jezik Doktorsko delo/naloga 2025-07-08 12:57:49 2026-02-16 14:01:13 2026-02-24 08:17:58 0000-00-00 00:00:00 2026 0 Maribor 0 Maribor XIII, 218 str. 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 581.524.2:595.76(043.3) 268605187 DOK_Horvat_Eva_2026.pdf DOK_Horvat_Eva_2026.pdf 1 0C610E191142A1F6145A26692377C7A1 ab156892222fadceb1a14c30167bfaac8b1dbdd26d909473e02c3a617bdbe8f2 0463a147-fddc-11f0-8805-00155d00018d https://dk.um.si/Dokument.php?lang=slv&id=202870 Fakulteta za naravoslovje in matematiko 0 0 0