Do bank voles (Myodes glareolus) trapped in live and lethal traps show differences in tick burden?

publishedVersio

Host in reserve: The role of common shrews (Sorex araneus) as a supplementary source of tick hosts in small mammal communities influenced by rodent population cycles

Rodents often act as important hosts for ticks and as pathogen reservoirs. At north -ern latitudes, rodents often undergo multi- annual population cycles, and the peri -odic absence of certain hosts may inhibit the survival and recruitment of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a sup -plementary host source to immature life stages (larvae and nymphs) of a generalist tick Ixodes ricinus and a small mammal specialist tick I. trianguliceps, during decreas-ing abundances of bank voles (Myodes glareolus). We used generalized mixed models to test whether ticks would have a propensity to parasitize a certain host species dependent on host population size and host population composition across two high- latitude gradients in southern Norway, by comparing tick burdens on trapped ani -mals. Host population size was defined as the total number of captured animals and host population composition as the proportion of voles to shrews. We found that a larger proportion of voles in the host population favored the parasitism of voles by I. ricinus larvae (estimate = −1.923, p= .039) but not by nymphs (estimate = −0.307,p= .772). I. trianguliceps larvae did not show a lower propensity to parasitize voles, regardless of host population composition (estimate = 0.875, p= .180), while nymphsparasitized shrews significantly more as vole abundance increased (estimate= 2.106, p= .002). These results indicate that common shrews may have the potential to act as a replacement host during periods of low rodent availability, but long- term observa-tions encompassing complete rodent cycles may determine whether shrews are able to maintain tick range expansion despite low rodent availability.publishedVersio

Digital læringsanalyse i grunnopplæringen: En kvalitativ studie av hva som karakteriserer læreres bruk av læringsanalytiske dashboard i grunnopplæringen

I norsk sammenheng har det de siste årene blitt rettet oppmerksomhet mot elevers bruk av digitale læremidler, og hvordan en kan bruke digital læringsanalyse for å forbedre elevers læring og undervisning. Digital læringsanalyse inngår i Kunnskapsdepartementets digitaliseringsstrategi for grunnopplæringen, og det er en ambisjon om god profesjonsfaglig digital kompetanse i grunnskole og videregående skole. «Bruk av læringsdata» og «datadrevet beslutningstaking» er populære mantraer, men implementeringen av digital læringsanalyse er komplekst. Samtidig peker forskningen på et gap mellom teori og praktisk anvendelse, og det er lite forskning som kan vise til effekten av digital læringsanalyse i undervisningssammenheng. I denne masteroppgaven rettes derfor søkelyset mot hva som karakteriserer læreres bruk av læringsanalytiske dashboard i grunnopplæringen. Masteroppgaven har et vitenskapsteoretisk ståsted innenfor konstruktivismen og baserer seg på et kvalitativt design. Gjennom kvalitative forskningsintervjuer av to aktører i Campus Inkrement og ni lærere i grunnopplæringen er formålet både å nyansere og berike det som «karakteriserer», i det som anses å være et relativt ungt forskningsfelt. Analysen av datamaterialet har en induktiv tilnærming med utgangspunkt i tematisk analyse, og funnene diskuteres med utgangspunkt i tidligere forskning på feltet og sosiokulturelle perspektiver på kunnskapsutvikling. Det teoretiske rammeverket gir dermed et teoretisk utgangspunkt for å forstå samspillet mellom kunnskapsutvikling og læringsanalytiske dashboard, i lys av medierende artefakter og medierende handlinger situert i sosial kontekst. Funnene viser at lærernes bruk av det læringsanalytiske dashboardet inkluderer å holde oversikt over elevenes aktivitet i Campus Matte, og en kan betrakte dashboardet som et metakognitivt verktøy. Samtidig anerkjenner lærerne det læringsanalytiske dashboardet som støtte for formativ vurdering, basert på de mulighetene som ligger til grunn i analyseverktøyet. Lærerne beskriver at den digitale læringsanalysen gir et unyansert blikk på læring, og det læringsanalytiske dashboardet bør snarere være et ledd i å utforske elevenes kunnskapsforståelse i sosial kontekst. I dette tilfellet viser det seg at dashboardet kan være et utgangspunkt for dialogbasert oppfølging, basert på manglende arbeidsinnsats og i hvilken grad elevene har fått til oppgavene i Campus Matte.In recent years attention has been directed towards students' use of digital learning resources and how learning analytics can be employed to enhance students' learning and teaching. Learning analytics is part of the Ministry of Education's digitalization strategy for primary and secondary education in Norway, with the ambition of promoting proficient digital competence among teachers. “Data use” and “data-based decision making” are popular mantras, but the implementation of learning analytics is complex. However, research highlights a gap between theory and practice, and there is limited research demonstrating the effectiveness of learning analytics in educational settings. This master's thesis therefore focuses on characterizing teachers' use of learning analytics dashboard in primary and secondary education. The master's thesis adopts a constructivist research paradigm and is based on a qualitative design. Through qualitative research interviews with two stakeholders from Campus Inkrement and nine teachers in primary and secondary education, the aim is to explore and enrich, in a nuanced way, the usefulness of what is considered to be a relatively new research field. The analysis of the data takes an inductive approach based on thematic analysis, and the findings are discussed in relation to previous research in the field and sociocultural perspectives on knowledge development. The theoretical framework thus provides a theoretical basis for understanding the interplay between knowledge development and learning analytics dashboard, considering mediating artifacts and mediating actions situated in social context. The findings indicate that teachers' use of the learning analytics dashboard includes monitoring students' activity in Campus Matte, positioning the dashboard as a metacognitive tool. At the same time, teachers recognize that the learning analytics dashboard is a support for formative assessment, based on the opportunities provided by the analytical tool. Teachers describe that the learning analytics provide a simplistic view of learning, and that the learning analytics dashboard should rather be a means to explore students' understanding of knowledge in a social context. In this case, it appears that the dashboard can serve as a starting point for dialogue-based intervention, based on insufficient effort and the extent to which students have completed tasks in Campus Matte.Masteroppgave i pedagogikkPED395MAPS-PE

Ortolan Buntings Emberiza hortulana mimicking other species and other dialects of own species

We present new acoustically well-documented observations of Ortolan Bunting males from Norway, singing atypical songs with syllables copied from other species and from non-neighbouring, distant populations of own species. The first case concerns a male singing strophes containing syllables of Yellowhammer and Ortolan Bunting, both most probably copied in central Europe. These songs often had broken syntax. The second case concerns a male that sang both typical strophes and strophes that had the initial part copied from a local dialect of Redwing, but with a typical syntax for the species. That male mated successfully. Causes and consequences of vocal mimicry in the species are discussed

Sex-biased breeding dispersal is predicted by social environment in birds

Sex- biased dispersal is common in vertebrates, although the ecological and evolu-tionary causes of sex differences in dispersal are debated. Here, we investigate sex differences in both natal and breeding dispersal distances using a large dataset on birds including 86 species from 41 families. Using phylogenetic comparative analyses, we investigate whether sex- biased natal and breeding dispersal are associated with sexual selection, parental sex roles, adult sex ratio (ASR), or adult mortality. We show that neither the intensity of sexual selection, nor the extent of sex bias in parental care was associated with sex- biased natal or breeding dispersal. However, breeding dispersal was related to the social environment since male-biased ASRs were associ-ated with female-biased breeding dispersal. Male-biased ASRs were associated withfemale- biased breeding dispersal. Sex bias in adult mortality was not consistently related to sex- biased breeding dispersal. These results may indicate that the rare sex has a stronger tendency to disperse in order to find new mating opportunities. Alternatively, higher mortality of the more dispersive sex could account for biased ASRs, although our results do not give a strong support to this explanation. Whichever is the case, our findings improve our understanding of the causes and consequences of sex- biased dispersal. Since the direction of causality is not yet known, we call for future studies to identify the causal relationships linking mortality, dispersal, and ASR

Evolution of dispersal strategies and dispersal syndromes in fragmented landscapes

Funded by ERA-Net BiodivERsAPeer reviewedPostprin

Island biogeography theory explains the genetic diversity of a fragmented rock ptarmigan (Lagopus muta) population

The island biogeography theory is one of the major theories in ecology, and its applicability to natural systems is well documented. The core model of the theory, the equilibrium model of island biogeography, predicts that species diversity on an island is positively related to the size of the island, but negatively related by the island's distance to the mainland. In recent years, ecologists have begun to apply this model when investigating genetic diversity, arguing that genetic and species diversity might be influenced by similar ecological processes. However, most studies have focused on oceanic islands, but knowledge on how the theory applies to islands located on the mainland (e.g., mountain islands, forest islands) is scarce. In this study, we examined how the size and degree of isolation of mountain islands would affect the genetic diversity of an alpine bird, the rock ptarmigan (Lagopus muta). Within our study area, we defined the largest contiguous mountain area as the mainland, while smaller mountains surrounding the mainland were defined as islands. We found that the observed heterozygosity (Ho) was significantly higher, and the inbreeding coefficient (Fis) significantly lower, on the mainland compared to islands. There was a positive significant relationship between the unbiased expected heterozygosity (Hn.b.) and island size (log km2), but a negative significant relationship between Ho and the cost distance to the mainland. Our results are consistent with the equilibrium model of island biogeography and show that the model is well suited for investigating genetic diversity among islands, but also on islands located on the mainland

High-elevational occurrence of two tick species, Ixodes ricinus and I. trianguliceps, at their northern distribution range

Background: During the last decades a northward and upward range shift has been observed among many organisms across different taxa. In the northern hemisphere, ticks have been observed to have increased their latitudinal and altitudinal range limit. However, the elevational expansion at its northern distribution range remains largely unstudied. In this study we investigated the altitudinal distribution of the exophilic Ixodes ricinus and endophilic I. trianguliceps on two mountain slopes in Norway by assessing larval infestation rates on bank voles (Myodes glareolus). Methods: During 2017 and 2018, 1325 bank voles were captured during the spring, summer and autumn at ten trapping stations ranging from 100 m to 1000 m.a.s.l. in two study areas in southern Norway. We used generalized logistic regression models to estimate the prevalence of infestation of both tick species along gradients of altitude, considering study area, collection year and season, temperature, humidity and altitude interactions as extrinsic variables, and host body mass and sex as intrinsic predictor variables. Results: We found that both I. ricinus and I. trianguliceps infested bank voles at altitudes up to 1000 m.a.s.l., which is a substantial increase in altitude compared to previous findings for I. ricinus in this region. The infestation rates declined more rapidly with increasing altitude for I. ricinus compared to I. trianguliceps, indicating that the endophilic ecology of I. trianguliceps may provide shelter from limiting factors tied to altitude. Seasonal effects limited the occurrence of I. ricinus during autumn, but I. trianguliceps was found to infest rodents at all altitudes during all seasons of both years. Conclusions: This study provides new insights into the altitudinal distribution of two tick species at their northern distribution range, one with the potential to transmit zoonotic pathogens to both humans and livestock. With warming temperatures predicted to increase, and especially so in the northern regions, the risk of tick-borne infections is likely to become a concern at increasingly higher altitudes in the future

Do bank voles (Myodes glareolus) trapped in live and lethal traps show differences in tick burden?

In studies assessing tick abundance, the use of live traps to capture and euthanize rodent hosts is a commonly used method to determine their burden. However, captive animals can experience debilitating or fatal capture stress as a result prior to collection. An alternative method is the use of lethal traps, but this can potentially lead to tick drop-off between the time of capture and collection. In this study, in order to determine whether subjecting animals to capture stress is inevitable, we tested the difference in sheep tick (Ixodes ricinus) larval burdens between bank voles (Myodes glareolus) captured alive and euthanized, and lethally trapped bank voles. During 2017 and 2018, 1318 bank voles were captured using live (Ugglan Special no. 2) and lethal (Rapp2 Mousetrap) traps during two consecutive years over three seasons in two locations in Norway. Voles captured alive would remain captive until euthanized, while lethally trapped voles were killed instantly upon capture. Loglinear models, accounting for overdispersion, were used to determine whether trap type was influencing observed tick burden. Bank voles captured in lethal traps carried 5.7% more larvae compared to euthanized voles captured in live traps, but this difference was not significant (p = 0.420). Males were overall captured 2.7 times more frequently than females, and the sex ratio was equal in both trap types. This study shows that the use of lethal traps to determine tick burden of rodents is sufficiently reliable, without having to subject animals to potentially lethal stress, hereby reducing some ethical concerns of animal suffering and the results thereof, without compromising accuracy. Lethal trapping is also often more economical and practical, further favoring this collection method

Host in reserve: The role of common shrews (Sorex araneus) as a supplementary source of tick hosts in small mammal communities influenced by rodent population cycles

Rodents often act as important hosts for ticks and as pathogen reservoirs. At north -ern latitudes, rodents often undergo multi- annual population cycles, and the peri -odic absence of certain hosts may inhibit the survival and recruitment of ticks. We investigated the potential role of common shrews (Sorex araneus) to serve as a sup -plementary host source to immature life stages (larvae and nymphs) of a generalist tick Ixodes ricinus and a small mammal specialist tick I. trianguliceps, during decreas-ing abundances of bank voles (Myodes glareolus). We used generalized mixed models to test whether ticks would have a propensity to parasitize a certain host species dependent on host population size and host population composition across two high- latitude gradients in southern Norway, by comparing tick burdens on trapped ani -mals. Host population size was defined as the total number of captured animals and host population composition as the proportion of voles to shrews. We found that a larger proportion of voles in the host population favored the parasitism of voles by I. ricinus larvae (estimate = −1.923, p= .039) but not by nymphs (estimate = −0.307,p= .772). I. trianguliceps larvae did not show a lower propensity to parasitize voles, regardless of host population composition (estimate = 0.875, p= .180), while nymphsparasitized shrews significantly more as vole abundance increased (estimate= 2.106, p= .002). These results indicate that common shrews may have the potential to act as a replacement host during periods of low rodent availability, but long- term observa-tions encompassing complete rodent cycles may determine whether shrews are able to maintain tick range expansion despite low rodent availability