Herbivore-Associated Bacteria as Potential Mediators and Modifiers of Induced Plant Defense Against Spider Mites and Thrips

Induced plant defense, comprising contact with exogenous stimuli, production of endogenous signals alerting the plant, associated biochemical cascades, and local and/or systemic expression of the defense mechanisms, critically depends on the nature of the inducing agents. At large, bio-trophic pathogenic microorganisms and viruses usually trigger the salicylate (SA)-mediated pathway, whereas necro-trophic pathogens and herbivores usually trigger the jasmonate (JA)-mediated pathway in plants. The SA- and JA-mediated pathways do not operate independently but commonly interfere with each other. Several recent studies revealed abnormal plant responses upon herbivore attack in diverse plant-herbivore systems. Observed abnormalities range from suppression of the common JA-pathway, induction of the SA-pathway to no response, yet the underlying proximate causes and ultimate consequences of these variations are elusive. Strikingly, some studies provide compelling evidence that anti-herbivore plant responses may decisively depend on bacteria associated with the herbivore attacking the plant (HAB for herbivore-associated bacteria). HAB may influence herbivore recognition by the plant and alter the biochemical cascades inside plants. Here, I report cases in point of HAB manipulating induced anti-herbivore plant responses, suggest spatial and temporal categorization of HAB, and point at proximate and ultimate aspects of plant defense manipulation by HAB. Following, I overview the diversity of HAB of spider mites and herbivorous thrips, argue that, considering recently reported phenomena of abnormal plant responses upon spider mite attack, some of these HAB could represent important, but hitherto largely neglected, mediators/modifiers of induced plant defense against spider mites and thrips, and conclude with suggestions for future research

Social familiarity modulates group living and foraging behaviour of juvenile predatory mites

Environmental stressors during early life may have persistent consequences for phenotypic development and fitness. In group-living species, an important stressor during juvenile development is the presence and familiarity status of conspecific individuals. To alleviate intraspecific conflicts during juvenile development, many animals evolved the ability to discriminate familiar and unfamiliar individuals based on prior association and use this ability to preferentially associate with familiar individuals. Assuming that familiar neighbours require less attention than unfamiliar ones, as predicted by limited attention theory, assorting with familiar individuals should increase the efficiency in other tasks. We assessed the influence of social familiarity on within-group association behaviour, development and foraging of juvenile life stages of the group-living, plant-inhabiting predatory mite Phytoseiulus persimilis. The observed groups consisted either of mixed-age familiar and unfamiliar juvenile mites or of age-synchronized familiar or unfamiliar juvenile mites or of pairs of familiar or unfamiliar larvae. Overall, familiar mites preferentially grouped together and foraged more efficiently, i.e. needed less prey at similar developmental speed and body size at maturity, than unfamiliar mites. Preferential association of familiar mites was also apparent in the inter-exuviae distances. Social familiarity was established by imprinting in the larval stage, was not cancelled or overridden by later conspecific contacts and persisted into adulthood. Life stage had an effect on grouping with larvae being closer together than nymphal stages. Ultimately, optimized foraging during the developmental phase may relax within-group competition, enhance current and future food supply needed for optimal development and optimize patch exploitation and leaving under limited food

Vergleich zweier Organisationsformen innerhalb des Konzerns Siemens Linz, unter Beachtung verschiedener Aspekte

Siemens Österreich ist ein gut strukturiertes Unternehmen und trotzdem gibt es Probleme, die interessant sind sie wissenschaftlich zu untersuchen. In dieser Arbeit geht um den Vergleich zweier Abteilungen (Automation and Drives und Industrial Solutions and Services) mit unterschiedlichen Organisationsformen, wobei die Hauptpunkte der Informationsaustausch zwischen Vorgesetzten und Angestellten und der Stolz der MitarbeiterInnen sind. Es werden aber auch Punkte wie die kürzlich durchgeführte Umstrukturierung, subjektiv gesehene Vor- und Nachteile der Oranisationsformen Projektorganisation und hierarchische Organisation sowie die Motivation der MitarbeiterInnen untersucht. Die Untersuchung der Forschungsfragen mit Hilfe leitfadengetützter ExpertInneninterviews und der Literaturanalyse brachten folgende Ergebnisse: Die Organisationsmitglieder nutzten sehr viele Wege für den Austausch von Informationen und trotzdem haben sie das Gefühlt zu wenig von der Leitung informiert zu werden. Durch die, in den Medien breit getretene, Schmiergeldaffäre und einer Änderung des Werteverständnisses sind die MitarbeiterInnen nicht mehr so stolz bei Siemens zu arbeiten. Überraschend waren auch Aussagen über die Möglichkeit der Teilzeitarbeit, der Schmiergeldaffäre und ihre Auswirkungen auf die MitarbeiterInnen sowie der kaum vorhandene Nachwuchs von Siemens

Interrelated effects of mycorrhiza and free-living nitrogen fixers cascade up to abovegr ound herbivores

Aboveground plant performance is strongly influenced by belowground microorganisms, some of which are pathogenic and have negative effects, while others, such as nitrogen-fixing bacteria and arbuscular mycorrhizal fungi, usually have positive effects. Recent research revealed that belowground interactions between plants and functionally distinct groups of microorganisms cascade up to aboveground plant associates such as herbivores and their natural enemies. However, while functionally distinct belowground microorganisms commonly co-occur in the rhizosphere, their combined effects, and relative contributions, respectively, on performance of aboveground plant-associated organisms are virtually unexplored. Here, we scrutinized and disentangled the effects of free-living nitrogen-fixing (diazotrophic) bacteria Azotobacter chroococcum (DB) and arbuscular mycorrhizal fungi Glomus mosseae (AMF) on host plant choice and reproduction of the herbivorous two-spotted spider mite Tetranychus urticae on common bean plants Phaseolus vulgaris. Additionally, we assessed plant growth, and AMF and DB occurrence and density as affected by each other. Both AMF alone and DB alone increased spider mite reproduction to similar levels, as compared to the control, and exerted additive effects under co-occurrence. These effects were similarly apparent in host plant choice, that is, the mites preferred leaves from plants with both AMF and DB to plants with AMF or DB to plants grown without AMF and DB. DB, which also act as AMF helper bacteria, enhanced root colonization by AMF, whereas AMF did not affect DB abundance. AMF but not DB increased growth of reproductive plant tissue and seed production, respectively. Both AMF and DB increased the biomass of vegetative aboveground plant tissue. Our study breaks new ground in multitrophic belowground–aboveground research by providing first insights into the fitness implications of plant-mediated interactions between interrelated belowground fungi–bacteria and aboveground herbivores.BK's stay and work in Vienna was financially supported by an Erasmus Mundus CASIA grant awarded to BK and a grant from Eurasia Pacific Uninet (EPU 26/2013) awarded to PS. TP's stay and work in Vienna was supported by Universitat Jaume I (UJI Research Mobility Grant, E-2013-05). We thank C. Gangl (Agrotrader Agrarhandel, Austria) for providing Azotobacter sp. and I.C. Christiansen, A. Walzer, and M. Seiter for comments on a previous version of the manuscript

Analogies and differences in optical and mathematical systems and approaches

Publication in the conference proceedings of SampTA, Bremen, Germany, 201

Використання інваріантів у визначенні інтеграції й диверсифікованості виробництва промислових підприємств

Успішний розвиток економіки багато в чому залежить від функціонування всіх її ланок. Важливу роль грає діагностика й організація процесів інтеграції й диверсифікованості виробництва промислових підприємств, що забезпечують підвищення стабільності, керованості й ефективність діяльності підприємств в умовах конкурентної боротьби