3,104 research outputs found
Butterfly fitness under changing food qualities
No full textThe present thesis investigates how different food qualities over the whole life cycle and
across generations affect butterfly development and reproduction, and addresses the following
main questions: (1) What effects have varying nitrogen concentration and different levels of
host plant defence during larval phase on larval and adult performance in butterflies? (2) Can
adult feeding in male and female butterflies compensate for deficiencies acquired during the
larval stage, or even increase butterfly fitness and reproductive success? (3) Does parental
food quality affect the next generation by parental effects (increased provisioning to
offspring, maternal oviposition choice or transgenerational acclimatization)?
With six distinctive experiments, I show that butterfly reproduction and fitness significantly
correlate with food quality and quantity. Thus, there are diverse strategies over the whole
butterfly life cycle to deal with suboptimal food sources in order to maximize reproduction
and fitness. First, during the larval stage, larval feeding duration can be prolonged and relative
consumption rates and/or efficiency of larval nitrogen utilization could be increased to
compensate for low-quality larval host plants. Second, adult nectar diet can compensate for
deficiencies acquired during larval stage and generally enhance reproduction. Furthermore,
female butterflies can use male-derived nuptial gifts for egg production. Third, parents can
increase provisioning to offspring and acclimatize and oviposit progeny to anticipated host
plants by transgenerational acclimatization to increase offspring performance and fitness.
These diverse strategies during larval and adult stage and even trans-generationally to
maximize reproduction and fitness show that butterflies are well adapted to quickly changing
host plant supplies. Furthermore, it shows that the holometabolous life cycle, using different
food sources during larval and adult stage, is a favorable surviving strategy
Reviewing the Author-Function in the Age of Wikipedia
No full textIn Reviewing the Author-Function in the Age of Wikipedia, Amit Ray and Erhardt Graeff examine how wiki technology challenges traditional concepts of authorship and authority in knowledge production. The authors build on poststructuralist theory, particularly Roland Barthes\u27s Death of the Author and Michel Foucault\u27s concept of the author-function, to analyze how wikis destabilize individual authorship in favor of collaborative, community-driven content creation.
The essay argues that wikis represent a fundamental shift from the Romantic notion of the solitary author-genius to what they term the wiki writing process —a dynamic system where traditional roles of reader, writer, and editor blur into a unified community of users. Using Wikipedia as a primary case study, the authors demonstrate how the platform\u27s structure (article, discussion, and history pages) creates a digital palimpsest that archives all contributions while enabling continuous revision.
Through analysis of Wikipedia\u27s editing patterns and community oversight mechanisms, Ray and Graeff show how wikis embody poststructuralist principles in practice, creating what they call serial collaborations that exist in perpetual flux. The authors conclude that wikis represent an evolved form of textual production that realizes Foucault\u27s vision of discourse freed from traditional authorial constraints, offering new possibilities for collaborative knowledge creation while challenging established notions of intellectual authority and ownership
The invasive plant Impatiens glandulifera affects mycorrhizal fungi, plant and invertebrate diversity in deciduous forests
No full textNon-native plant species have the potential to affect an ecosystem by changing species diversity, community structure and interactions among organisms. It is therefore important to understand potential mechanisms that contribute to the success of invasive plants. In the context of my PhD thesis, I examined the effect of the invasive annual herb I. glandulifera on mycorrhizal, plant and invertebrate diversity in a deciduous forest near Basel (Switzerland). I also studied the potential mechanism that could contribute to the success of I. glandulifera. A controlled field experiment was set up in three forest areas that were affected to a different extend (little, moderatly, high) by a former wind storm. In each area, three different plot types were installed: plots invaded by I. glandulifera, plots from which the invasive plants had been manually removed and plots which were no yet colonized by the invasive plant. The results of my thesis demonstrate that I. glandulifera affects above and as well as belowground organisms and has the potential to change soil conditions.
Aboveground gastropod richness and abundance were found to be higher in invaded plots than in control plots. The presence of I. glandulifera also altered the composition of gastropod species. Belowground fewer types of ectomycorrhiza were found on root systems of F. sylvatica saplings. Moreover, in plots with I. glandulifera the composition of ectomycorrhiza morphotypes was shifted. Considering mycorrhizal colonisation on fine roots saplings of both tree species, the presence of the invasive plant resulted in a reduction of ectomycorrhizal colonisation of F. sylvatica saplings and of arbuscular mycorrhiza colonisation on A. pseudoplatanus. Thus, disruption of mycorrhizal symbiosis probably led to a lower biomass and survival rate in saplings of both species grown in invaded plots. Additional results showed that soil moisture, soil pH, available phosphorus and microbial activity were increased in invaded plots.
Increased gastropods abundance and richness could be explained by higher soil moistures and damped soil temperature in invaded plots. However, measured changes in soil conditions did not affect mycorrhizal colonisation and performance of both sapling species. Therefore allelopatic effects of I. glandulifera on mycorrhizal symbioses were also examined. Allelopatic compounds are known to contribute to the spread of some invasive plant species and can disrupt mycorrhizal symbiosis. I identified the allelopathic compound 2-methoxy-1,4-naphtoquinone (2-MNQ) in plant organs of I. glandulifera, in soil of its proximity and in rain water rinsed from its leaves. Specific bioassays using shoot and root extracts of I. glandulifera as well as synthetic 2-MNQ revealed strong inhibitory effects on mycelium growth of ectomycorrhiza fungi and on the germination of native forest herbs. This finding indicates that the release of 2-MNQ may contribute to the invasion success of I. glandulifera.
Health, function and diversity of forest ecosystems are closely linked to the abundance and richness of mycorrhizal fungi. This study demonstrates that the spread I. glandulifera into deciduous forest ecosystem resulted in lower mycorrhizal colonisation of saplings. Thus, forest regeneration might be strongly affected by I. glandulifera. Moreover, changes in soil chemistry and soil conditions induced by I. glandulifera caused shifts in above- and belowground communities. Therefore ecosystem services and functions of forest habitats can be affected. Removal or stopping the preceding spread of I. glandulifera may be an investment for the conservation of native species and may prevent potential losses in timber production
Business School_Response To Request for Syllabi/Information About Pandemic-Related Courses and Activities Email
No full textEmail thread of the response from the Maine School Business to the request for syllabi/information about pandemic-related courses and activities from the Provost Office. Content was submitted by Tracy B. Bigney, Cooperating Instructor, University of Maine to Niclas Erhardt, Associate Dean, Maine Business School, University of Maine
The Agersoe cattle : the last remnants of the Danish island cattle (Bos taurus)?
No full textThe following members of the European Cattle Genetic diversity consortium contributed to this study: Lenstra, J. A., Nijman, I. J. (both Utrecht University, The Netherlands); Moazami-Goudarzi, K. (INRA, Jouy-en-Josas, France); Erhardt, G., Wiemann, C., Prinzenberg, E.-M. (Justus-Liebig Universität, Germany); Harlizius, B. (School of Vetenary Medicine, Germany); Looft, C., Kalm, E. (Christian-Albrechts, Universität, Germany); Kantanen, J. (MTT, Finland); Olsaker, I. (Norwegian School of Vetenary Sciences); Holm, L. E. (Danish Institute of Agricultural Sciences, Denmark).vo
Traditional versus sprinkler irrigation of mountain hay meadows in the Valais : consequences for biodiversity
No full textSemi-natural grasslands including hay meadows belong to the most species-rich habitats in central Europe and are therefore of high conservation value. The high biodiversity of these grasslands has been maintained for many centuries through the regular disturbance by traditional management practices. In the Valais, an arid mountain region of Switzerland, traditional management of hay meadows includes irrigation by open water channels. In the past decades, however, the traditional irrigation technique was increasingly replaced by more efficient sprinkler-irrigation systems or irrigation was stopped on marginal and poorly accessible areas. Within the scope of this thesis, four studies were conducted to investigate different aspects of these changes in meadow irrigation.
The aim of the first study was to examine whether land-use abandonment resulting from the cessation of irrigation influenced the biodiversity of hay meadows in the Valais. For this purpose, plant and gastropod surveys were conducted in three serial stages of succession (hay meadows, early abandoned meadows and young forests). Meadow abandonment resulted in an increase in gastropod species richness and a loss of plant and gastropod species characteristic for open grassland habitats. Furthermore, functional traits of plants (plant height, the start of seed shedding and the type of reproduction) and gastropods (shell size) were affected by abandonment.
Traditional meadow irrigation is assumed to distribute the water more heterogeneously than sprinkler irrigation, which might affect meadow biodiversity as well as the distribution of plants in a small scale. The aim of the second study was to examine whether the change from traditional to sprinkler irrigation affected the local biodiversity (plants and gastropods) of hay meadows in the Valais. A high plant species richness was found in the hay meadows investigated. The diversity and composition of plant and gastropod species did not differ between traditionally and sprinkler-irrigated meadows. However, the installation of sprinkler systems resulted in an increase in the grass-to-forb ratio and affected the leaf distribution and the start of seed shedding in plants.
The third study aimed to investigate whether the change in irrigation technique affected the small-scale distribution of plants and soil characteristics in these hay meadows. Three sampling plots consisting of 13 subplots of increasing size were installed in traditionally and sprinkler-irrigated meadows to assess plant species richness and soil characteristics within subplots. The type of irrigation technique did not affect the shape of the plant species-area relationship. Furthermore, spatial autocorrelation in the soil characteristics examined was low and their small-scale distributions were mostly not influenced by the irrigation technique. These findings indicate a pronounced small-scale heterogeneity in the distribution of plant species and soil characteristics in the hay meadows investigated. Therefore, as practiced in our study areas, the distribution of water by sprinklers might be less homogenous than commonly assumed.
The abandonment of traditional management practices of semi-natural grasslands is suggested to result in a reduced landscape heterogeneity, which in turn might contribute to the loss of local plant diversity. The fourth study aimed to investigate whether the change from traditional to sprinkler irrigation resulted in alterations in the surrounding landscape of species-rich hay meadows. Furthermore, we asked if plant diversity of differently irrigated meadows is influenced by landscape composition and the heterogeneity of the surrounding landscape. Landscape composition was more diverse for traditionally than for sprinkler-irrigated meadows, but did not differ prior to the installation of sprinklers. A diverse small-scale landscape composition in the close surroundings of hay meadows had a positive effect on the number of generalists but not on total plant species richness or the number of specialists. Finally, sprinkler-irrigated meadows had an increased number of generalist plant species.
The findings of this thesis suggest that the installation of sprinklers did not affect the local species richness of plants and gastropods in the hay meadows investigated. Nevertheless, the change in irrigation technique influenced functional aspects of plant diversity (plant traits, grass-to-forb ratio and generalist species). Furthermore, the installation of sprinklers was associated with a homogenization of the landscape, which may eventually result in an intensification of land use. For the conservation of the biodiversity of these hay meadows it is recommended to maintain the relatively extensive irrigation and management practices
Milk protein polymorphism in taurine (Bos taurus) and zebu (Bos indicus) populations bred in hot climate
No full textThe genetic variation at four milk protein loci alpha(s1)-casein (CSN1S1), beta-casein (CSN2), kappa-casein (CSN3) and beta-lactoglobulin (LGB) was investigated in 358 animals belonging to seven populations well adapted to hot climatic conditions, reared in Africa and Italy. Bos taurus (Somba, Lagune and Modicana), Bos indicus (Sudanese Zebu Peul, Azaouak and Adamawa), and B. taurus x B. indicus (Borgou) were studied by adapting different molecular methodologies to evaluate their genetic variability. All loci were polymorphic and a new CSN2 synonymous variant, named A(2'), was detected and characterized. Noteworthy differences in the distribution of alleles and haplotypes were observed between zebuine and taurine cattle showing that milk protein polymorphism is suited for discriminating B. taurus from B. indicus efficiently, and also taurine breeds. Milk protein loci, being positively selected loci, can also provide information about the occurrence of germplasm particularly useful for breeding strategies and production improvement
Short communication: Milk protein genetic variation and casein haplotype structure in the Original Pinzgauer cattle
No full textMilk protein genetic polymorphisms are often used for characterizing domesticated mammalian species and breeds, and for studying associations with economic traits. The aim of this work was to analyze milk protein genetic variation in the Original Pinzgauer, a dual-purpose (dairy and beef) cattle breed of European origin that was influenced in the past by human movements from different regions as well as by crossbreeding with Red Holstein. A total of 485 milk samples from Original Pinzgauer from Austria (n=275) and Germany (n=210) were typed at milk proteins alphaS1-casein, beta-casein, kappa-casein, alpha-lactalbumin, and beta-lactoglobulin by isoelectrofocusing to analyze the genetic variation affecting the protein amino acid charge. The Original Pinzgauer breed is characterized by a rather high genetic variation affecting the amino acid charge of milk proteins, with a total of 15 alleles, 12 of which were found at a frequency >0.05. The most polymorphic protein was beta-casein with 4 alleles detected. The prevalent alleles were CSN1S1*B, CSN2*A 2 , CSN1S2*A, CSN3*A, LGB*A, and LAA*B. A relatively high frequency of CSN1S2*B (0.202 in the whole data set) was found, mainly occurring within the C-A 2 -B-A haplotype (in the order CSN1S1-CSN2-CSN1S2-CSN3), which seems to be peculiar to the Original Pinzgauer, possibly because the survival of an ancestral haplotype or the introgression of Bos indicus
Distribution, life history, food choice and chemical ecology of the invasive box-tree pyralid "cydalima perspectalis"
No full textSUMMARY: The box-tree pyralid Cydalima perspectalis (Walker 1859) (Lepidoptera: Pyralidae)
is a new invasive moth species in Europe. Its larvae feed on box-tree leaves and
can cause severe damage within short time. Therefore, this species is of great
concern for park and public garden manager in Europe.
In the context of my PhD thesis, I examined the spread in the region of Basel,
the national distribution as well as the biology of this moth. The natural
dispersal speed was assessed using a public survey in the region of Basel.
The number of adult moths caught with light traps allowed the determination of
two distinct periods of appearance of adult moths: the first in July and the
second, less pronounced, from September to mid-October.
In collaboration with CABI Switzerland in Delémont, a geographic model based
on literature data from Europe and Asia as well as field and laboratory data was
developed. It shows the potential distribution, life-history and relative
abundance of the box-tree pyralid in Europe. The model suggests that the box-tree
pyralid might spread across most of Europe, except North Fenno-Scandinavia,
Northern Scotland and high mountain regions, where the overall temperatures are
too low to allow the completion of an entire generation per year. In most parts
of Central Europe, two generations of C. perspectalis may occur, whereas in
Northern and North-Western Europe, low temperatures allow only one yearly
generation.
In an experiment, a potential preference of the box-tree pyralid for a particular
box-tree variety was investigated. Female moths deposited their eggs preferably
on varieties with large leaves. Larval growth and survival did not differ between
the five most frequently planted box-tree varieties in Central Europe, suggesting
that the box-tree pyralid has a broad food acceptance in Europe. The discrepancy
between adult preference and larval performance could be explained by the fact
that the larval generation which was tested in this experiment was only about the
tenth in Central Europe, and that the adaptation to the new ecosystem is not fully
accomplished yet.
Another study involving chemical analyses showed that larvae take up toxic
compounds (alkaloids) from the box-tree leaves on which they feed and therefore
become unpalatable for predators. Young larvae contain twice as much alkaloids as
larvae in later instars. In box-tree leaves, the concentration of alkaloids
doubles between one year-old leaves and older leaves. This finding suggests a
preference of larvae for leaves containing a high concentration of alkaloids,
which may explain why damage on a box-tree most often starts in the lower part,
where the oldest leaves are found.
Finally, an instrument for decision-making when facing the choice of long-term
care and replacement of large box-tree plantations was developed using the example
of the cemetery “am Hörnli” in Riehen, close to Basel. The cemetery “am Hörnli”
would suffer a great financial damage due to the loss of box-trees, having
estimated 3.3 km of box-tree hedges and 650 solitary trees. Since a replacement of
all box-tree plants does neither come into consideration financially nor
materially, the municipal parks and garden department chose a financially more
attractive solution for the clearance, care, and replacement of box-trees,
following a concept of commensurability and efficiency: important trees from a
heritage point of view are management and functionally less important trees are
cleared and replaced by optically different but less pricy plants or not replaced
at all. This strategy proves to be the most cost-efficient: after only four years
this strategy is financially more attractive than a hypothetical care of all
box-tree plants.
The findings of this doctoral thesis suggest that it will become unavoidable to
monitor box-trees in gardens, parks and in natural sites and to treat them with
pesticides in case of need. ---------- Zusammenfassung: Der Buchsbaumzünsler Cydalima perspectalis (Walker 1859) (Lepidoptera: Pyralidae)
ist eine in Europa neu auftretende, invasive Schmetterlingsart, dessen Raupen sich
von Buchsblättern ernähren. Diese können innert kurzer Zeit grosse Schäden
anrichten und bereiten daher den Verantwortlichen für Parks und Grünanlagen in
Europa grosse Sorgen.
Im Rahmen meiner Dissertation untersuchte ich die regionale und nationale
Ausbreitung sowie die Biologie des Falters. Mittels einer Umfrage bei der
Bevölkerung der Region Basel wurde die natürliche Ausbreitungs-geschwindigkeit des
Buchsbaumzünslers erfasst. Mithilfe der Aufzeichnung von Lichtfängen an zwei
Standorten in Basel konnten zwei deutlich getrennte Perioden des Erscheinens der
Falter festgestellt werden: die erste im Juli und die zweite, weniger stark
ausgeprägte, von Anfang September bis Mitte Oktober.
In Zusammenarbeit mit CABI Switzerland in Delémont wurde ein geographisches Modell
erstellt, welches anhand von Literaturdaten aus Europa und Asien sowie Feld- und
Labor-Daten die potentielle Verbreitung, die relative Abundanz sowie den
jährlichen Rhythmus des Buchsbaumzünslers in Europa simuliert. Das Modell lässt
darauf schliessen, dass sich der Buchsbaumzünsler in ganz Europa ausbreiten kann,
mit Ausnahme vom nördlichen Fennoskandinavien, dem Norden Schottlands und hohen
Bergregionen wo die Temperaturen insgesamt zu niedrig sind, um eine komplette
Generation pro Jahr auszubilden. In weiten Teilen Mitteleuropas bildet der
Schädling zwei jährliche Generationen aus. In Nordeuropa erlauben die tieferen
Temperaturen hingegen nur eine einzige Generation pro Jahr.
Mit einem Experiment wurde eine allfällige Buchsbaum-Sortenpräferenz des
Buchsbaumzünslers untersucht. Legebereite Weibchen zeigten eine Vorliebe für
grossblättrige Buchssorten. Die Wachstumsrate und Sterblichkeit der Raupen zeigten
keine Unterschiede zwischen den häufigsten Sorten in Mitteleuropa, was darauf
schliessen lässt, dass der Buchsbaumzünsler in Europa eine breite Futterpflanzen-
akzeptanz aufweist. Die Abweichung zwischen der Präferenz der Falter und der
Wachstumsrate der Raupen kann daraus herrühren, dass die getesteten Raupen und
Falter erst etwa die zehnte Generation ist, welche in Mitteleuropa auftritt, und
die Anpassung an das neue Ökosystem noch nicht optimiert wurde.
In einer weiteren Untersuchung konnte anhand von chemischen Analysen gezeigt
werden, dass die Raupen giftige Stoffe (Alkaloide) aus den Buchsblättern aufnehmen
und speichern und deshalb für Frassfeinde ungeniessbar sind. Junge Raupen weisen
einen doppelt so hohen Alkaloidgehalt auf wie spätere Stadien. Beim Buchs sind
die Alkaloidkonzentration in einjährigen Blättern nur etwa halb so gross ist wie
in älteren Blättern. Diese Beobachtung legt nahe, dass Raupen Blätter mit hohem
Alkaloidgehalt vorziehen, was erklären mag weshalb der Frass an einer Buchspflanze
meist im unteren Bereich anfängt, wo die ältesten Blätter sind.
Es wurde ebenfalls ein Instrument zur Entscheidungsfindung zwischen Ersatz oder
langjähriger Pflege grosser Buchsbestände anhand des Friedhofes am Hörnli in
Riehen bei Basel entwickelt, da dieser mit seinen geschätzten 3.3 km Buchshecken
und 650 Solitärbuchsbäumen von einem erheblichen finanziellen Schaden durch den
Verlust von Buchs betroffen ist. Da ein Ersatz aller Buchspflanzen weder
finanziell noch materiell in Frage kommt, wird von der Stadtgärtnerei –
entsprechend dem Konzept der Verhältnismässigkeit – ein weit niedrigerer Betrag
für Rodung, Ersatz und Pflege aufgewendet: Denkmal-pflegerisch wichtige
Buchspflanzen werden erhalten und gepflegt, funktionell weniger wichtige
Buchspflanzen gerodet und je nach Situation gar nicht oder durch optisch
verschiedene aber dafür günstigere Straucharten ersetzt. Diese Strategie erweist
sich als die rentabelste: bereits nach vier Jahren ist diese Strategie finanziell
attraktiver als eine hypothetische Pflege des gesamten Buchsbestandes.
Aufgrund der verschiedenen Erkenntnisse, welche im Verlauf dieser Doktorarbeit
gewonnen wurden, wird es in Zukunft unvermeidlich sein, Buchspflanzen in Gärten,
Parkanlagen und an natürlichen Standorten zu überwachen und notfalls mit
Insektenschutzmitteln zu behandeln
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