Search

With climate change, spring warming tends to advance plant leaf-out. While the timing of leaf-out has been shown to affect the quality of leaves for herbivores in spring, it is unclear whether such effects extend to herbivores active in summer. In this study, we first examined how spring and autumn phenology of seven Quercus robur genotypes responded to elevated temperatures in spring. We then tested whether the performance of two summer-active insect herbivores (Orthosia gothica and Polia nebulosa) and infection by a pathogen (Erysiphe alphitoides) were influenced by plant phenology, traits associated with genotype or the interaction between these two. Warm spring temperatures advanced both bud development and leaf senescence in Q. robur. Plants of different genotype differed in terms of both spring and autumn phenology. Plant phenology did not influence the performance of two insect herbivores and a pathogen, while traits associated with oak genotype had an effect on herbivore performance. Weight gain for O. gothica and ingestion for P. nebulosa differed by a factor of 4.38 and 2.23 among genotypes, respectively. Herbivore species active in summer were influenced by traits associated with plant genotype but not by phenology. This suggest that plant attackers active in summer may prove tolerant to shifts in host plant phenology-a pattern contrasting with previously documented effects on plant attackers active in spring and autumn.

Climate change is advancing the onset of phenological events, with the rate of advance varying among species and trophic levels. In addition, local populations of the same species may show genetic differences in their response to seasonal cues. If populations of interacting species differ in their response, then climate change may result in geographically varying shifts in the community-level distribution of interaction strength. We explored the magnitude of trophic- and species-level responses to temperature in a tritrophic system comprising pedunculate oak, insect herbivores, and their associated parasitoids. We sampled local realizations of this community at five sites along a transect spanning fifteen degrees of latitude. Samples from each trophic level at each site were exposed to the same set of five climatic regimes during overwintering in climate chambers. We then recorded the number of days and degree-days required for oak acorns to develop and insects to emerge. In terms of dates of events, phenology differed among populations. In terms of degree-days, we found that for two species pairs, the heat sum required to develop in spring differed by an additional ∼500 degree-days between trophic levels when overwintering at the highest temperature. For three species, within-population variation in the number of degree-days required for emergence was higher at warmer temperatures. Our findings suggest that changing temperatures can modify interactions within a community by altering the relative phenology of interacting species and that some interactions are more vulnerable than others to a shift in temperature. The geographic variation in the phenological response of a species suggests that there is a genetic component in determining the phenology of local populations. Such local variation blended with interspecific differences in responses makes it complex to understand how communities will respond to warmer temperatures.

Climate change may alter the dynamics of outbreak species by changing the phenological synchrony between herbivores and their host plants. As host plant phenology has a genotypic component that may interact with climate, infestation levels among genotypes might change accordingly. When the outbreaking herbivore is active early in the season, its infestation levels may also leave a detectable imprint on herbivores colonizing the plant later in the season. In this study, we first investigated how the spring phenology and genotype of Quercus robur influenced the density of the spring-active, outbreaking leaf miner Acrocercops brongniardellus. We then assessed how intraspecific density affected the performance of A. brongniardellus and how oak genotype and density of A. brongniardellus affected the insect herbivore community. We found that Q. robur individuals of late spring phenology were more strongly infested by A. brongniardellus. Conspecific pupae on heavily infested oaks tended to be lighter, and fewer heterospecific insect herbivores colonized the oak later in the season. Beyond its effects through phenology, plant genotype left an imprint on herbivore species richness and on two insect herbivores. Our results suggest a chain of knock-on effects from plant phenology, through the outbreaking species to the insect herbivore community. Given the finding of how phenological synchrony between the outbreak species and its host plant influences infestation levels, a shift in synchrony may then change outbreak dynamics and cause cascading effects on the insect community.

1. Variation in spring phenology - like tree budburst - affects the structure of insect communities, but impacts of autumn phenology have been neglected. Many plant species have recently delayed their autumn phenology, and the timing of leaf senescence may be important for herbivorous insects. 2. This study explored how an insect herbivore community associated with Quercus robur is influenced by variation in autumn phenology. For this, schools were asked to record, across the range of oak in Sweden, the autumn phenology of oaks and to conduct a survey of the insect community. 3. To tease apart the relative impacts of climate from that of tree phenology, regional tree phenology was first modelled as a function of regional climate, and the tree-specific deviation from this relationship was then used as the metric of relative tree-specific phenology. 4. At the regional scale, a warmer climate postponed oak leaf senescence. This was also reflected in the insect herbivore community: six out of 15 taxa occurred at a higher incidence and five out of 18 taxa were more abundant, in locations with a warmerclimate. Similarly, taxonomic richness and herbivory were higher in warmer locations. 5. Trees with a relatively late autumn phenology had higher abundances of leaf miners (Phyllonorycter spp.). This caused lower community diversity and evenness on trees with later autumn phenology. 6. The findings of the present study illustrate that both regional climate-driven patterns and local variation in oak autumn phenology contribute to shaping the insect herbivore community. Community patterns may thus shift with a changing climate.

Som blivande gymnasielärare i ämnet musik har intresset för betyg, dess påverkan och betydelse för yrket, skapat denna uppsats. Därför är syftet med studien att undersöka hur betyg på gymnasiet påverkar musiklärarens undervisning. Hur arbetar musikläraren med bedömning för betygsättning i undervisningen? Hur påverkas musiklärarens undervisning av betygssättning? Studien utgår från en kvalitativ inriktning. Genom intervjuer med aktiva och legitimerade musiklärare visar resultaten att många gymnasielärare i musik påverkas av betygsättning före, under och efter undervisningen. Många lärare planerar utifrån kunskapskraven istället för det centrala innehållet. Resultatet visar också hur lärare arbetar med kunskapskraven. I min diskussion problematiseras det faktum att lärarna planerar lektioner utifrån kunskapskrav istället för centralt innehåll. Vidare diskuteras att betyg och behov inte alltid faller samman samt hur betyg påverkar dialogen och återkoppling lärare till elev., As a future high school teacher in the subject of music, interest in grades, its impact and importance for the profession, created this essay. Therefore, the purpose of the study is to investigate how the grades of high school affects the teaching of music teachers. How does the music teacher work with assessments in the classroom? How is music teacher's teaching affected by assessments? The study is based on a qualitative approach. Through interviews with certified music teachers active in the new grade system, the results show that many high school teachers in music are influenced by grades before, during and after their lessons. Many teachers plan on the basis of knowledge requirements instead of the core content. The result also shows how teachers work with the knowledge requirements. In my discussion, the fact that teachers plan lessons based on knowledge requirements instead of central content is problematized. Furthermore, it is discussed that grades and needs do not always coincide and also how grades affect the dialogue and feedback, teacher to student.