Biology subjects

Mullon, C.

Publications and source records attributed to Mullon, C..

4 recordsLinked to original sources

bioRxiv2018

A quantitative genetics model for the dynamics of phenotypic (co)variances under limited dispersal, with an application to the coevolution of socially synergistic traits

Darwinian evolution consists of the gradual transformation of heritable quantitative traits due to natural selection and the input of random variation by mutation. Here, we use a quantitative genetics approach to investigate the coevolution of multiple traits under selection, mutation, and limited dispersal. We track the dynamics of trait means and variance-covariances between traits that experience frequency-dependent selection. Assuming a multivariate-normal trait distribution, we recover classical dynamics of quantitative genetics, as well as stability and evolutionary branching conditions of invasion analyses, except that due to limited dispersal, selection depends on indirect fitness effects and relatedness. In particular, correlational selection that associates different traits within-individuals depends on the fitness effects of such associations between-individuals. These kin selection effects can be as relevant as pleiotropy for correlation between traits. We illustrate this with an example of the coevolution of two social traits whose association within-individual is costly but synergistically beneficial between-individuals. As dispersal becomes limited and relatedness increases, associations between-traits between-individuals become increasingly targeted by correlational selection. Consequently, the trait distribution goes from being bimodal with a negative correlation under panmixia to unimodal with a positive correlation under limited dispersal. More broadly, our approach can help understand the evolution of intra-specific variation.

evolutionary biology↗

bioRxiv2017

Eco-evolutionary dynamics under limited dispersal: ecological inheritance, altruism within and spite between species

Understanding selection on ecological interactions that take place in dispersal-limited communities is an important challenge for ecology and evolutionary biology. The problem is that local demographic stochasticity generates eco-evolutionary dynamics that are too complicated to make tractable analytical investigations. Here, we circumvent this problem by approximating the selection gradient on a quantitative trait that influences local community dynamics, assuming that such dynamics are deterministic with a stable fixed point, but incorporating the kin selection effects arising from demographic stochasticity. Our approximation reveals that selection depends on how an individual expressing a trait-change influences: (1) its own fitness and the fitness of its current relatives; and (2) the fitness of its downstream relatives through modifications of local ecological conditions (i.e., through ecological inheritance). Mathematically, the effects of ecological inheritance on selection are captured by dispersal-limited versions of press-perturbations of community ecology. We use our approximation to investigate the evolution of helping within- and harming between-species when these behaviours influence demography. We find helping evolves more readily when competition is for material resources rather than space because then, the costs of kin competition are paid by downstream relatives. Similarly, harming between species evolves when it alleviates downstream relatives from inter-specific competition. Beyond these examples, our approximation can help better understand the influence of ecological inheritance on a variety of eco-evolutionary dynamics, from plant-pollinator to predator-prey coevolution.

evolutionary biology↗

bioRxiv2017

Co-evolution of dispersal with behaviour favours social polymorphism

Dispersal determines gene flow among groups in a population and so plays a major role in many ecological and evolutionary processes, from biological invasions to species extinctions. Because patterns of gene flow shape kin structure, dispersal is also important to the evolution of social behaviours that influence reproduction and survival within groups. Conversely, dispersal patterns depend on kin structure and social behaviour. Dispersal and social behaviour therefore co-evolve but the nature and consequences of this interplay are not well understood. Here, we model this co-evolution and show that it readily leads to the emergence and maintenance of two broadly-defined social morphs: a sessile, benevolent morph expressed by individuals who tend to increase the fecundity of others within their group relative to their own; and a dispersive, selfserving morph expressed by individuals who tend to increase their own fecundity relative to others within their group. This social polymorphism arises as a consequence of a positive linkage between the loci responsible for dispersal and social behaviour, leading to benevolent individuals preferentially interacting with relatives and self-serving individuals with non-relatives. We find that this positive linkage is favoured under a large spectrum of conditions, which suggests that an association between dispersal proclivity and other social traits should be common in nature. In line with this prediction, dispersing individuals across a wide range of organisms have been reported to differ in their social tendencies from non-dispersing individuals.

evolutionary biology↗

bioRxiv2017

Invasion fitness for gene-culture co-evolution in the family and an application to cumulative culture under vertical transmission

Human evolution depends on the co-evolution between genetically determined behaviors and socially transmitted information. Although vertical transmission of cultural information from parent to off-spring is common in hominins, its effects on cumulative cultural evolution are not fully understood. Here, we investigate gene-culture co-evolution in a family-structured population by studying the invasion fitness of a mutant allele that influences a deterministic level of cultural information (e.g., amount of knowledge or skill) to which diploid carriers of the mutant are exposed in subsequent generations. We show that the selection gradient on such a mutant, and the concomitant level of cultural information it generates, can be evaluated analytically under the assumption that the cultural dynamic has a single attractor point, thereby making gene-culture co-evolution in family-structured populations with multigenerational effects mathematically tractable. We apply our result to study how genetically determined phenotypes of individual and social learning co-evolve with the level of adaptive information they generate under vertical transmission. We find that vertical transmission increases adaptive information due to kin selection effects, but when information is transmitted as efficiently between family members as between unrelated individuals, this increase is moderate in diploids. By contrast, we show that the way resource allocation into learning trades off with allocation into reproduction (the \"learning-reproduction trade-off\") significantly influences levels of adaptive information. We also show that vertical transmission prevents evolutionary branching and may therefore play a qualitative role in gene-culture co-evolutionary dynamics. More generally, our analysis of selection suggests that vertical transmission can significantly increase levels of adaptive information under the biologically plausible condition that information transmission between relatives is more efficient than between unrelated individuals.

evolutionary biology↗