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Sökning: WFRF:(Arvanitis Leena)

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2.
  • Arvanitis, Leena, et al. (författare)
  • Butterfly seed predation: effects of landscape characteristics, plant ploidy level and population structure
  • 2007
  • Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 152:2, s. 275-285
  • Tidskriftsartikel (refereegranskat)abstract
    • Polyploidization has been suggested as one of the most common mechanisms for plant diversification. It is often associated with changes in several morphological, phenological and ecological plant traits, and therefore has the potential to alter insect–plant interactions. Nevertheless, studies evaluating the effect of plant polyploidy on interspecific interactions are still few. We investigated pre-dispersal seed predation by the butterfly Anthocharis cardamines in 195 populations of two ploidy levels of the herb Cardamine pratensis (tetraploid ssp. pratensis, 2n = 30 vs. octoploid ssp. paludosa, 2n = 56–64). We asked if differences in incidence and intensity of predation among populations were related to landscape characteristics, plant ploidy level and population structure. The incidence of the seed predator increased with increasing plant population size and decreasing distance to nearest population occupied by A. cardamines. The intensity of predation decreased with increasing plant population size and was not affected by isolation. Probability of attack decreased with increasing shading, and intensity of predation was higher in grazed than in non-grazed habitats. The attack intensity increased with increasing mean flower number of plant population, but was not affected by flowering phenology. Individuals in tetraploid populations suffered on average from higher levels of seed predation, had higher mean flower number, were less shaded and occurred more often in grazed habitats than octoploid populations. When accounting for differences in habitat preferences between ploidy levels there was no longer a difference in intensity of predation, suggesting that the observed differences in attack rates among populations of the two ploidy levels are mediated by the habitat. Overall, our results suggest that polyploidization is associated with differentiation in habitat preferences and phenotypic traits leading to differences in interspecific interaction among plant populations. This, in turn, may facilitate further divergence of ploidy levels.
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3.
  • Arvanitis, Leena, et al. (författare)
  • Novel antagonistic interactions associated with plant polyploidization influence trait selection and habitat preference.
  • 2010
  • Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 13:3, s. 330-7
  • Tidskriftsartikel (refereegranskat)abstract
    • Polyploidization is an important mechanism for sympatric speciation in plants. Still, we know little about whether plant polyploidization leads to insect host shifts, and if novel interactions influence habitat and trait selection in plants. We investigated herbivory by the flower bud gall-forming midge Dasineura cardaminis on tetraploids and octoploids of the herb Cardamine pratensis. Gall midges attacked only octoploid plant populations, and a transplantation experiment confirmed this preference. Attack rates were higher in populations that were shaded, highly connected or occurred along stream margins. Within populations, late-flowering individuals with many flowers were most attacked. Galling reduced seed production and significantly influenced phenotypic selection on flower number. Our results suggest that an increase in ploidy may lead to insect host shifts and that plant ploidy explains insect host use. In newly formed plant polyploids, novel interactions may alter habitat preferences and trait selection, and influence the further evolution of cytotypes.
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4.
  • Arvanitis, Leena, et al. (författare)
  • Plant ploidy level influences selection by butterfly seed predators
  • 2008
  • Ingår i: Oikos. ; 117, s. 1020-1025
  • Tidskriftsartikel (refereegranskat)abstract
    • Polyploidization is a common route to plant diversification. Polyploids often differ from their progenitors in size, flower number, flower size and flowering phenology. Such differences may translate into differences in the intensity of interactions with animals. Here we investigated the impact of the ploidy-related differences in tetraploids and octoploids of the perennial herb Cardamine pratensis on pre-dispersal seed predation by the butterfly Anthocharis cardamines. The probability of escaping attack was lower for octoploids than for tetraploids, even after accounting for the fact that octoploids were larger and had fewer flowers than tetraploids. Flower shoot size was correlated with probability of attack in tetraploids but not in octoploids. Differences in plant traits associated with polyploidization can alter interactions with animals, and animal-mediated differences in trait selection between ploidy types can contribute to their further divergence.
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5.
  • Arvanitis, Leena, 1959- (författare)
  • Plant polyploidy and interactions with insect herbivores
  • 2007
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Polyploidization has been suggested to be a common mechanism for plant speciation. Polyploidy is associated with changes in plant traits and altered habitat preference. Antagonistic and mutualistic animals are known to discriminate between plants based on variation in such plant traits, suggesting that interactions may have an important role in divergence of plant polyploids after the polyploidization. In this thesis, I investigated the effect of insect herbivores on divergence of plant polyploids in a system consisting of the predispersal seed predator butterfly Anthocharis cardamines, the bud gall forming midge Dasineura cardaminis, and tetraploids and octoploids of the herb Cardamine pratensis. Octoploid populations occurred more often in shaded and nongrazed habitats than tetraploids. Octoploid plants were larger and had fewer but larger flowers than tetraploids. Butterfly attack rates were higher in tetraploid than in octoploid populations, whereas the gall midge attacked only octoploids. These differences were associated with higher abundance of butterflies in sunny habitats and gall midges in shaded habitats. In contrast to the pattern at the population level, octoploid flower shoots were more likely to be attacked by the butterfly in sympatric populations. Also trait selection differed between ploidy levels, both in the absence and in the presence of herbivores. In a field experiment, butterfly preference did not alter the trait selection in tetraploids. In octoploids, the two herbivores did not change selection considered separately. However, their joint effect resulted in significant selection for smaller flower shoots and reduced selection on number of flowers. This thesis demonstrates that differences in habitat preference and phenotypic plant traits between polyploid cytotypes can lead to altered interactions with herbivores. Such differences in interactions with animals may alter not only the relative fitness of cytotypes but also trait selection within the respective ploidy type.
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  • Boalt, Elin, et al. (författare)
  • The association among herbivory tolerance, ploidy level, and herbivory pressure in cardamine pratensis
  • 2010
  • Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 24:5, s. 1101-1113
  • Tidskriftsartikel (refereegranskat)abstract
    • We tested whether differences in ploidy level and previous exposure to herbivory can affect plant tolerance to herbivory. We conducted a common garden experiment with 12 populations of two ploidy levels of the perennial herb Cardamine pratensis (five populations of tetraploid ssp. pratensis and seven populations of octoploid ssp. paludosa). Earlier studies have shown that attack rates by the main herbivore, the orange tip butterfly Anthocharis cardamines, are lower in populations of octoploids than in populations of tetraploids, and vary among populations. In the common garden experiment, a combination of natural and artificial damage significantly reduced seed and flower production. We measured tolerance based on four plant-performance metrics: survival, growth, seed production and clonal reproduction. For three of these measurements, tolerance of damage did not differ between ploidy levels. For clonal reproduction, the octoploids had a higher tolerance than the tetraploids, although they experience lower herbivore attack rates in natural populations. Populations from sites with high levels of herbivory had higher tolerance, measured by seed production, than populations with low levels of herbivory. We did not detect any significant costs of tolerance. We conclude that high intensity of herbivory has selected for high tolerance measured by seed production in C. pratensis.
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8.
  • Hamza, Karim Mikael, 1967-, et al. (författare)
  • Nature of science in students’ discussions on disagreement between scientists following a narrative about health effects of the Fukushima Daiichi accident
  • 2023
  • Ingår i: International Journal of Science Education. - : Informa UK Limited. - 0950-0693 .- 1464-5289. ; 45:1, s. 22-42
  • Tidskriftsartikel (refereegranskat)abstract
    • We explored the potential for addressing nature of science through a historic narrative about disagreement between researchers concerning a socio-scientific issue, incidence of juvenile thyroid cancer following the Fukushima Daiichi nuclear accident. The narrative was developed from authentic sources and tested in two cycles. Eight groups of three to four high-school students were audio recorded. Transcripts were analyzed regarding what nature of science emerged in the discussions and what understanding about NOS could be discerned, using three complementary NOS-frameworks (Consensus-NOS, Whole Science-NOS, FRA-NOS). Together, the student groups touched upon 19 different NOS-themes as they tried to make sense of the disagreement related in the narrative. All groups addressed a common core of NOS-themes, most of which were central to the narrative itself, although some themes that were not part of the narrative also emerged. Students displayed a basic understanding of the tentative, empirical, and subjective nature of science together with the role of evidential relevance and completeness of evidence related to the choice of scientific methods. On the other hand, students did not reckon with peer review as a means for establishing knowledge and resolving disagreement. Moreover, although students readily accepted disagreement as a basic property of science, they had difficulty handling this disagreement when coping with the SSI in the narrative. We discuss how the combination of history of science-in-the-making and SSI in narrative form offers opportunities to teach NOS without risking simplified messages of how scientific knowledge develops or how science can be used to address socio-scientific issues.
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9.
  • Lundegård, Iann, 1955-, et al. (författare)
  • Facts and values in students’ reasoning about gene technology in the frame of risk–a thick comprehension
  • 2022
  • Ingår i: Environmental Education Research. - : Informa UK Limited. - 1350-4622 .- 1469-5871. ; 28:9, s. 1283-1296
  • Tidskriftsartikel (refereegranskat)abstract
    • In the current debate, there is no consensus on the relationship between knowledge and values in students’ reasoning and argumentation in socio-scientific and sustainability issues, i.e. if these should be addressed as separate entities or rather treated as a whole. In this study, we address this question empirically, with students engaging in two language games–aesthetic and epistemological–as they deliberate on ethical issues associated with genetic engineering. The study reports on a course unit that includes lectures, group work and student-led value-clarification exercises. The ways in which the language games interact were analysed using the established methods of Practical Epistemology Analysis (PEA) and analysis of Deliberative Educational Questions (DEQ). Our results show that aesthetic and epistemological language games were intricately intertwined in the students’ reasoning. Given this close entanglement, each language game was conducive to the development of the other and in so doing, deepened the understanding of the content as a whole.
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10.
  • Schenk, Linda, 1980-, et al. (författare)
  • Socioscientific Issues in Science Education : An opportunity to Incorporate Education about Risk and Risk Analysis?
  • 2021
  • Ingår i: Risk Analysis. - : Wiley. - 0272-4332 .- 1539-6924. ; 41:12, s. 2209-2219
  • Tidskriftsartikel (refereegranskat)abstract
    • Socioscientific issues (SSI) concern social issues, often lacking simple solutions, that relate to science and often also risk controversies. SSIs have become an established part of science education, aiming to teach students not only about content knowledge but also about the nature of science and to offer them practice in argumentation and decision making. We performed a scoping review of the literature on SSI in science education research, in order to investigate if the topics covered would lean themselves to education about risk, and if risk is raised in these works. Using Web of Science we identified 296 empirical publications and 91 theoretical or review publications about SSI teaching in science education. The empirical publications covered studies performed in primary to tertiary school, most commonly upper secondary school (32%). The most frequently taught SSI themes were nature conservation, biotechnology, and climate change. Despite that these, as most of the other identified themes, clearly are connected to risk analysis and risk management, few publications raised the concept of risk and the methods of risk analysis. In fact, almost half (empirical: 48%, theoretical: 49%) did not mention risk at all. We argue that SSIs present an opportunity for risk researchers to engage with educators to incorporate risk in school science education and to contribute in developing teaching materials suitable toward that aim.
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