TY - JOUR AB - Natural selection is usually studied between mutants that differ in reproductive rate, but are subject to the same population structure. Here we explore how natural selection acts on mutants that have the same reproductive rate, but different population structures. In our framework, population structure is given by a graph that specifies where offspring can disperse. The invading mutant disperses offspring on a different graph than the resident wild-type. We find that more densely connected dispersal graphs tend to increase the invader’s fixation probability, but the exact relationship between structure and fixation probability is subtle. We present three main results. First, we prove that if both invader and resident are on complete dispersal graphs, then removing a single edge in the invader’s dispersal graph reduces its fixation probability. Second, we show that for certain island models higher invader’s connectivity increases its fixation probability, but the magnitude of the effect depends on the exact layout of the connections. Third, we show that for lattices the effect of different connectivity is comparable to that of different fitness: for large population size, the invader’s fixation probability is either constant or exponentially small, depending on whether it is more or less connected than the resident. AU - Tkadlec, Josef AU - Kaveh, Kamran AU - Chatterjee, Krishnendu AU - Nowak, Martin A. ID - 14657 IS - 208 JF - Journal of the Royal Society, Interface TI - Evolutionary dynamics of mutants that modify population structure VL - 20 ER - TY - JOUR AB - The growth of snail shells can be described by simple mathematical rules. Variation in a few parameters can explain much of the diversity of shell shapes seen in nature. However, empirical studies of gastropod shell shape variation typically use geometric morphometric approaches, which do not capture this growth pattern. We have developed a way to infer a set of developmentally descriptive shape parameters based on three-dimensional logarithmic helicospiral growth and using landmarks from two-dimensional shell images as input. We demonstrate the utility of this approach, and compare it to the geometric morphometric approach, using a large set of Littorina saxatilis shells in which locally adapted populations differ in shape. Our method can be modified easily to make it applicable to a wide range of shell forms, which would allow for investigations of the similarities and differences between and within many different species of gastropods. AU - Larsson, J. AU - Westram, Anja M AU - Bengmark, S. AU - Lundh, T. AU - Butlin, R. K. ID - 7651 IS - 163 JF - Journal of The Royal Society Interface SN - 1742-5689 TI - A developmentally descriptive method for quantifying shape in gastropod shells VL - 17 ER - TY - JOUR AB - We consider a class of students learning a language from a teacher. The situation can be interpreted as a group of child learners receiving input from the linguistic environment. The teacher provides sample sentences. The students try to learn the grammar from the teacher. In addition to just listening to the teacher, the students can also communicate with each other. The students hold hypotheses about the grammar and change them if they receive counter evidence. The process stops when all students have converged to the correct grammar. We study how the time to convergence depends on the structure of the classroom by introducing and evaluating various complexity measures. We find that structured communication between students, although potentially introducing confusion, can greatly reduce some of the complexity measures. Our theory can also be interpreted as applying to the scientific process, where nature is the teacher and the scientists are the students. AU - Ibsen-Jensen, Rasmus AU - Tkadlec, Josef AU - Chatterjee, Krishnendu AU - Nowak, Martin ID - 198 IS - 140 JF - Journal of the Royal Society Interface TI - Language acquisition with communication between learners VL - 15 ER -