Evolution of dispersal distance: Maternal investment leads to bimodal dispersal kernels

Since dispersal research has mainly focused on the evolutionary dynamics of dispersal rates, it remains unclear what shape evolutionarily stable dispersal kernels have. Yet, detailed knowledge about dispersal kernels, quantifying the statistical distribution of dispersal distances, is of pivotal importance for understanding biogeographic diversity, predicting species invasions, and explaining range shifts. We therefore examine the evolution of dispersal kernels in an individual-based model of a population of sessile organisms, such as trees or corals. Specifically, we analyze the influence of three potentially important factors on the shape of dispersal kernels: distance-dependent competition, distance-dependent dispersal costs, and maternal investment reducing an offspring's dispersal costs through a trade-off with maternal fecundity. We find that without maternal investment, competition and dispersal costs lead to unimodal kernels, with increasing dispersal costs reducing the kernel's width and tail weight. Unexpectedly, maternal investment inverts this effect: kernels become bimodal at high dispersal costs. This increases a kernel's width and tail weight, and thus the fraction of long-distance dispersers, at the expense of simultaneously increasing the fraction of non-dispersers. We demonstrate the qualitative robustness of our results against variations in the tested parameter combinations

Intense or Spatially Heterogeneous Predation Can Select against Prey Dispersal

Dispersal theory generally predicts kin competition, inbreeding, and temporal variation in habitat quality should select for dispersal, whereas spatial variation in habitat quality should select against dispersal. The effect of predation on the evolution of dispersal is currently not well-known: because predation can be variable in both space and time, it is not clear whether or when predation will promote dispersal within prey. Moreover, the evolution of prey dispersal affects strongly the encounter rate of predator and prey individuals, which greatly determines the ecological dynamics, and in turn changes the selection pressures for prey dispersal, in an eco-evolutionary feedback loop. When taken all together the effect of predation on prey dispersal is rather difficult to predict. We analyze a spatially explicit, individual-based predator-prey model and its mathematical approximation to investigate the evolution of prey dispersal. Competition and predation depend on local, rather than landscape-scale densities, and the spatial pattern of predation corresponds well to that of predators using restricted home ranges (e.g. central-place foragers). Analyses show the balance between the level of competition and predation pressure an individual is expected to experience determines whether prey should disperse or stay close to their parents and siblings, and more predation selects for less prey dispersal. Predators with smaller home ranges also select for less prey dispersal; more prey dispersal is favoured if predators have large home ranges, are very mobile, and/or are evenly distributed across the landscape

"To work, or not to work, that is the question" – recent trends and avenues for research on presenteeism

This position paper brings together recent and emerging developments in the field of presenteeism. A critical synthesis of the evidence is needed due to persisting conceptual and methodological challenges as well as the increased volume of research in the field. This paper integrates emerging evidence and critical thinking into three areas: (1) concept, (2) measurement and methodological issues, and (3) the context of presenteeism. First, due to the variety of existing definitions, competing understandings, as well as the notion of positive presenteeism, it is important to reconsider the notion of presenteeism. Second, it is important to reflect on the measurement of the act of presenteeism and the productivity loss associated with that. Third, following the call to investigate presenteeism in specific contexts, it is important to explain the social, occupational, cross-cultural aspects, as well as the contemporary workplace changes. Based on this critical synthesis, we conclude by identifying recommendations for future research on presenteeism

On the destructiveness of laissez-faire versus abusive supervision: A comparative, multilevel investigation of destructive forms of leadership

Different forms of destructive leadership are prevalent in organizations, but rarely studied together. Additionally, most studies take an individual-level view on the consequences of destructive leadership. However, while most supervisors lead teams, it remains unclear how destructive leadership behaviours affect team processes and outcomes from a multilevel perspective. Building on this premise, we analysed the relationship of abusive supervision and laissez-faire leadership with OCB on the individual and team-level. As an important team process, we considered team trust as a mediating mechanism. Further, we investigated whether laissez-faire leadership is more harmful to OCB compared to abusive supervision. We tested our proposed model in a three-wave study with data from 658 team members out of 149 teams. Bayesian multilevel analysis generally supported our assumptions: Abusive supervision lowered team trust and subsequently OCB at the individual and team-level, whereas laissez-faire was not related to team trust on the team-level. Additionally, our results indicated that laissez-faire was more harmful to OCB than abusive supervision on both levels. Finally, implications for theory and practical use in organizations are discussed