Biology subjects

Nitschke, M. C.

Publications and source records attributed to Nitschke, M. C..

2 recordsLinked to original sources

bioRxiv2024

Evolution of human pair bonds as a consequence of male-biased mating sex ratios?

Compared to our closest primate relatives, human life history involves greater longevity, which includes a distinctive postmenopausal life stage. The extension of the human lifes-pan (and continued fertility in old males) without lengthening female fertility directly changes the ratio of fertile males to fertile females, called the adult sex ratio (ASR). Additionally, this affects a more fine-grained ratio, the operational sex ratio (OSR), defined as the ratio of males to females currently able to conceive. Here, we construct an ODE model with minimal age structure, in which males compete for paternities using either a multiple-mating or mate-guarding strategy. Our focus is on investigating the differences of strategy choice between populations with chimpanzee-like and human-like life histories. By simulating the system, we determine the dominant strategy and its dependence on various parameter combinations. We introduce a new measure we call the lifetime paternity opportunities (LPO) of a given male strategy. The LPO directly calculates the payoffs of different male strategies and hence enables us to predict when strategies may shift. Our results show that an increase in OSR and ASR correlates well with a change in the dominant strategy from multiple mating to guarding.

evolutionary biology↗

bioRxiv2022

The Effect of Bottleneck Size on Evolution in Nested Darwinian Populations

Previous work has shown how a minimal ecological structure consisting of patchily distributed resources and recurrent dispersal between patches can scaffold Darwinian properties onto collections of cells. When the timescale of dispersal is long compared with the time to consume resources, patches evolve such that their size increases, but at the expense of cells whose growth rate decreases within patches. This creates the conditions that initiate evolutionary transitions in individuality. A key assumption of this scaffolding is that a bottleneck is created during dispersal, so patches are founded by single cells. The bottleneck decreases competition within patches and hence creates a strong hereditary link at the level of patches. Here we construct a fully stochastic model of nested Darwinian populations and investigate how larger bottlenecks affect the evolutionary dynamics at both cell and collective levels. It is shown that, up to a point, larger bottlenecks simply slow the dynamics, but at some point, which depends on the parameters of the within-patch model, the direction of evolution toward the equilibrium is reversed. Introducing random bottleneck sizes with some positive probability of smaller sizes can counteract this, even if the probability of smaller bottlenecks is small.

evolutionary biology↗