Risky movement increases the rate of range expansion.

The movement rules used by an individual determine both its survival and dispersal success. Here, we develop a simple model that links inter-patch movement behaviour with population dynamics in order to explore how individual dispersal behaviour influences not only its dispersal and survival, but also the population's rate of range expansion. Whereas dispersers are most likely to survive when they follow nearly straight lines and rapidly orient movement towards a non-natal patch, the most rapid rates of range expansion are obtained for trajectories in which individuals delay biasing their movement towards a non-natal patch. This result is robust to the spatial structure of the landscape. Importantly, in a set of evolutionary simulations, we also demonstrate that the movement strategy that evolves at an expanding front is much closer to that maximizing the rate of range expansion than that which maximizes the survival of dispersers. Our results suggest that if one of our conservation goals is the facilitation of range-shifting, then current indices of connectivity need to be complemented by the development and utilization of new indices providing a measure of the ease with which a species spreads across a landscape.

Evolution of dispersal in metacommunities of interacting species.

Theoretical studies on the evolution of dispersal in metacommunities are rare despite empirical evidence suggesting that interspecific interactions can modify dispersal behaviour of organisms. To understand the role of species interactions for dispersal evolution, we utilize an individual-based model of a metacommunity where local population dynamics follows a stochastic version of the Nicholson-Bailey model and dispersal probability is an evolving trait. Our results show that in comparison with a neutral system (commensalism), parasitism promotes dispersal of hosts and parasites, while mutualism tends to reduce dispersal in both partners. Search efficiency of guests (only in the case of parasitism), dispersal mortality and external extinction risk can influence the evolution of dispersal of all partners. In systems composed of two host and two guest species, lower dispersal probabilities evolve under parasitism as well as mutualism than in one host and one guest species systems. This is because of frequency-dependent modulations of dispersal benefits emerging in such systems for all partners.

The role of mobility for the emergence of diversity in victim-exploiter systems.

Theoretical and empirical studies indicate that exploitation is a possible driver of exploiter and victim diversification. However, there are many factors which could promote and limit this diversification process. Using a spatially explicit individual-based model, where an exploiter's success depends on matching between its own and a victim's continuous trait, we simulate local communities of victims and exploiters. We investigate how exploiter mobility (searching ability and movement strategies) can influence diversification of victims. We find that if victim traits are under intermediate intensity of stabilizing selection, disruptive selection exerted by exploiters can indeed lead to diversification in victim population and the victim trait distribution can split into two or more groups. Searching ability and movement strategy of exploiters (local vs. global movement) play a role in determining the number of victim trait groups emerging. Moreover, they affect the proportion of infected victims and the formation of spatial patterns in the victim trait distribution. In addition, with a high searching ability, exploiters with global movement drive victims to be more diverse than exploiters with local movement.

Women temporarily synchronize their menstrual cycles with the luminance and gravimetric cycles of the Moon.

Many species synchronize reproductive behavior with a particular phase of the lunar cycle to increase reproductive success. In humans, a lunar influence on reproductive behavior remains controversial, although the human menstrual cycle has a period close to that of the lunar cycle. Here, we analyzed long-term menstrual recordings of individual women with distinct methods for biological rhythm analysis. We show that women's menstrual cycles with a period longer than 27 days were intermittently synchronous with the Moon's luminance and/or gravimetric cycles. With age and upon exposure to artificial nocturnal light, menstrual cycles shortened and lost this synchrony. We hypothesize that in ancient times, human reproductive behavior was synchronous with the Moon but that our modern lifestyles have changed reproductive physiology and behavior.

Evolution of reduced dispersal mortality and 'fat-tailed' dispersal kernels in autocorrelated landscapes.

Models describing the evolution of dispersal strategies have mostly focused on the evolution of dispersal rates. Taking trees as a model for organisms with undirected, passive dispersal, we have developed an individual-based, spatially explicit simulation tool to investigate the evolution of the dispersal kernel, P(r), and its resulting cumulative seed-density distribution, D(r). Simulations were run on a variety of fractal landscapes differing in the fraction of suitable habitat and the spatial autocorrelation. Starting from a uniform D(r), evolution led to an increase in the fraction of seeds staying in the home cell, a reduction of the dispersal mortality (arrival in unsuitable habitat), and the evolution of 'fat-tailed' D(r) in autocorrelated landscapes and approximately uniform D(r) in random landscapes. The evolutionary process was characterized by long periods of stasis with a few bouts of rapid change in the dispersal rate.