University of Konstanz

About: University of Konstanz is a education organization based out in Konstanz, Baden-Württemberg, Germany. It is known for research contribution in the topics: Population & Membrane. The organization has 12115 authors who have published 27401 publications receiving 951162 citations. The organization is also known as: University of Constance & Universität Konstanz.

Interindividual variability in social insects - proximate causes and ultimate consequences

Abstract: Individuals within social groups often show consistent differences in behaviour across time and context. Such interindividual differences and the evolutionary challenge they present have recently generated considerable interest. Social insects provide some of the most familiar and spectacular examples of social groups with large interindividual differences. Investigating these within-group differences has a long research tradition, and behavioural variability among the workers of a colony is increasingly regarded as fundamental for a key feature of social insects: division of labour. The goal of this review is to illustrate what we know about both the proximate mechanisms underlying behavioural variability among the workers of a colony and its ultimate consequences; and to highlight the many open questions in this research field. We begin by reviewing the literature on mechanisms that potentially introduce, maintain, and adjust the behavioural differentiation among workers. We highlight the fact that so far, most studies have focused on behavioural variability based on genetic variability, provided by e.g. multiple mating of the queen, while other mechanisms that may be responsible for the behavioural differentiation among workers have been largely neglected. These include maturational, nutritional and environmental influences. We further discuss how feedback provided by the social environment and learning and experience of adult workers provides potent and little-explored sources of differentiation. In a second part, we address what is known about the potential benefits and costs of increased behavioural variability within the workers of a colony. We argue that all studies documenting a benefit of variability so far have done so by manipulating genetic variability, and that a direct test of the effect of behavioural variability on colony productivity has yet to be provided. We emphasize that the costs associated with interindividual variability have been largely overlooked, and that a better knowledge of the cost/benefit balance of behavioural variability is crucial for our understanding of the evolution of the mechanisms underlying the social organization of insect societies. We conclude by highlighting what we believe to be promising but little-explored avenues for future research on how within-colony variability has evolved and is maintained. We emphasize the need for comparative studies and point out that, so far, most studies on interindividual variability have focused on variability in individual response thresholds, while the significance of variability in other parameters of individual response, such as probability and intensity of the response, has been largely overlooked. We propose that these parameters have important consequences for the colony response. Much more research is needed to understand if and how interindividual variability is modulated in order to benefit division of labour, homeostasis and ultimately colony fitness in social insects.

Urbanization and its effects on personality traits: a result of microevolution or phenotypic plasticity?

Abstract: Human-altered environmental conditions affect many species at the global scale. An extreme form of anthropogenic alteration is the existence and rapid increase of urban areas. A key question, then, is how species cope with urbanization. It has been suggested that rural and urban conspecifics show differences in behaviour and personality. However, (i) a generalization of this phenomenon has never been made; and (ii) it is still unclear whether differences in personality traits between rural and urban conspecifics are the result of phenotypic plasticity or of intrinsic differences. In a literature review, we show that behavioural differences between rural and urban conspecifics are common and taxonomically widespread among animals, suggesting a significant ecological impact of urbanization on animal behaviour. In order to gain insight into the mechanisms leading to behavioural differences in urban individuals, we hand-raised and kept European blackbirds (Turdus merula) from a rural and a nearby urban area under common-garden conditions. Using these birds, we investigated individual variation in two behavioural responses to the presence of novel objects: approach to an object in a familiar area (here defined as neophilia), and avoidance of an object in a familiar foraging context (defined as neophobia). Neophilic and neophobic behaviours were mildly correlated and repeatable even across a time period of one year, indicating stable individual behavioural strategies. Blackbirds from the urban population were more neophobic and seasonally less neophilic than blackbirds from the nearby rural area. These intrinsic differences in personality traits are likely the result of microevolutionary changes, although we cannot fully exclude early developmental influences.

Muon spin rotation study of the correlation between Tc and ns/m* in overdoped Tl2Ba2CuO6+ delta.

Abstract: The muon spin depolarization rate \ensuremath{\sigma} was measured in overdoped ${\mathrm{Tl}}_{2}$${\mathrm{Ba}}_{3}$${\mathrm{CuO}}_{6+\mathrm{\ensuremath{\delta}}}$. \ensuremath{\sigma}(T\ensuremath{\rightarrow}0) was found to decrease proportional to the superconducting transition temperature ${\mathit{T}}_{\mathit{c}}$ as doping \ensuremath{\delta} is increased. In the framework of the clean-limit London model, \ensuremath{\sigma}(0)\ensuremath{\sim}${\ensuremath{\lambda}}^{\mathrm{\ensuremath{-}}2}$\ensuremath{\sim}${\mathit{n}}_{\mathit{s}}$/${\mathit{m}}^{\mathrm{*}}$, this implies that the depression of ${\mathit{T}}_{\mathit{c}}$ by overdoping is associated with a decrease of the superconducting condensate density ${\mathit{n}}_{\mathit{s}}$ in spite of the increasing normal-state carrier density. This can be largely accounted for in terms of strong pair breaking, which depresses both the condensate density and ${\mathit{T}}_{\mathit{c}}$ with increased doping.

Coherent control of a classical nanomechanical two-level system

Abstract: Coherent control of two flexural modes of a nanoscale oscillator using radiofrequency signals is now demonstrated. This oscillator is analogous to quantum two-level systems such as superconducting circuits and quantum dots, and therefore this technique raises the possibility of information processing using nanomechanical resonators.

Erroneous efficiency reports harm organic solar cell research

Abstract: Mischaracterization of solar cell power conversion efficiencies and widespread publication of inconsistent data in scientific journals threatens to undermine progress in organic and hybrid photovoltaics research.