Xavier Thibert-Plante

LANDR Audio Inc. · Research

Modern speciation theory has greatly benefited from a variety of simple mathematical models focusing on the conditions and patterns of speciation and diversification in the presence of gene flow. Unfortunately the application of general theoretical concepts and tools to specific ecological systems remains a challenge. Here we apply modeling tools t...

Speciation is the process that generates biodiversity, but recent empirical findings show that it can also fail, leading to the collapse of two incipient species into one. Here, we elucidate the mechanisms behind speciation collapse using a stochastic individual‐based model with explicit genetics. We investigate the impact of two types of environme...

Background: Over the last 300 years, interactions between alewives and zooplankton communities in several lakes in the U.S. have caused the alewives' morphology to transition rapidly from anadromous to landlocked. Lakes with landlocked alewives contain smaller-bodied zooplankton than those without alewives. Landlocked adult alewives display smaller...

Phenotypic plasticity is the ability of one genotype to produce different phenotypes depending on environmental conditions. Several conceptual models emphasize the role of plasticity in promoting reproductive isolation and, ultimately, speciation in populations that forage on two or more resources. These models predict that plasticity plays a criti...

Habitat preference may promote adaptive divergence and speciation, yet the conditions under which this is likely are insufficiently explored. We use individual-based simulations to study the evolution and consequence of habitat preference during divergence with gene flow, considering four different underlying genetically-based behavioral mechanisms...

Non-random mating provides multiple evolutionary benefits and can result in speciation. Biological organisms are characterised by a myriad of different traits, many of which can serve as mating cues. We consider multiple mechanisms of non-random mating simultaneously within a unified modelling framework in an attempt to understand better which are...

Compared to the vast literature linking competitive interactions and speciation, attempts to understand the role of facilitation for evolutionary diversification remain scarce. Yet, community ecologists now recognize the importance of positive interactions within plant communities. Here, we examine how facilitation may interfere with the mechanisms...

Many factors could influence progress towards sympatric speciation. Some of the potentially important ones include competition, mate choice and the degree to which alternative sympatric environments (resources) are discrete. What is not well understood is the relative importance of these different factors, as well as interactions among them. We use...

We use an individual-based numerical simulation to study the effects of phenotypic plasticity on ecological speciation. We find that adaptive plasticity evolves readily in the presence of dispersal between populations from different ecological environments. This plasticity promotes the colonization of new environments but reduces genetic divergence...

It is not yet clear under what conditions empirical studies can reliably detect progress toward ecological speciation through the analysis of allelic variation at neutral loci. We use a simulation approach to investigate the range of parameter space under which such detection is, and is not, likely. We specifically test for the conditions under whi...

Question: How does optimal size at the beginning of the juvenile stage vary with dissolved oxygen and aquatic predator pressure? Mathematical methods: An implicit model based on earlier offspring size and number optimality models, using empirical observations to motivate and interpret the results. Key assumptions: A stable, density-independent syst...

Questions: Do evolutionary changes in the levels of phenotypic plasticity occur after anthropogenic disturbance? Do these changes tend to be increases or decreases in plasticity? How do these evolutionary patterns differ among taxa and trait types? Does plasticity evolution change with time since the disturbance? Data incorporated: Evolutionary rat...

We use an individual-based simulation model to investigate factors influencing progress toward ecological speciation. We find that environmental differences can quickly lead to the evolution of substantial reproductive barriers between a population colonizing a new environment and the ancestral population in the old environment. Natural selection a...

A suite of simple metrics that can be used to analyse three-dimensional data sets is presented. We show how these metrics can be applied to raster-based, ecological mosaics sampled over uniform time intervals, such as might be obtained from a series of photographs or from repeated spatial sampling in the field. In these analyses, the concept of a 2...

We here employ 11 microsatellite markers and recently developed litter reconstruction methods to infer mating system parameters (i.e. polyandry and breeding-site fidelity) at a lemon shark nursery site in Marquesas Key, Florida. Four hundred and eight juvenile or subadult sharks were genotyped over eight complete breeding seasons. Using this inform...

The structure of interaction plays an important role in the outcome of evolutionary games. This study investigates the evolution of stochastic strategies of the prisoner's dilemma played on structures ranging from lattices to small world networks. Strategies and payoffs are analyzed as a function of the network characteristics of the node they are...

We examine the role played by crossover in a series of genetic algorithm-based evolutionary simulations of the iterated prisoner's dilemma. The simulations are characterized by extended periods of stability, during which evolutionarily meta-stable strategies remain more or less fixed in the population, interrupted by transient, unstable episodes tr...

We show that it is possible with easy-to-program algorithms to reach spatial resolutions of the order of 10 8 grid points for computing the electric potential on 2D periodic lattices, such as the Si(111)7 × 7 surface. We have used a spectral Fourier technique and parallelized FFTs with OPEN_MP on SGI machines. This method can be easily extended to...

The Poisson equation is a partial differential equation with a universal applicability embracing gravity, porous flow, materials science, and biochemical surfaces.Thus far most Poisson equations have been restricted to a relatively low resolution on the order of a thousand grid points along each direction. The imaging of nano to meso features on la...

The process by which one species becomes many (speciation) was considered by Darwin to be the mystery of mysteries. Speciation is no longer a complete mystery, but we still have a lot to discover about its mechanisms. Of particular interest is the process where reproductive isolation evolves as a byproduct of local adaptation, called ecological spe...