Biology subjects

Aubier, T. G.

Publications and source records attributed to Aubier, T. G..

8 recordsLinked to original sources

bioRxiv2025

Perceptual maps reveal rampant convergence in butterfly wing patterns across the Neotropics

In 1879, Fritz Muller formulated the first mathematical evolutionary model to explain mutualistic mimicry between coexisting defended prey. Yet, whether local mimicry drives the structure of aposematic prey signals across their entire geographic distribution remains untested because the perception of pattern similarity has never been assessed at large spatial scale. Here, we implement a citizen science survey to map, throughout the Neotropics, variation in the wing patterns of heliconiine butterflies (Nymphalidae) as perceived by vertebrate cognitive systems. We show that despite a continuum of perceived similarity in wing patterns at the continental scale, the convergence of sympatric species into discrete mimicry rings is ubiquitous among local communities. These results expand Mullers historical predictions by quantifying the rampant convergence of prey signals across an entire continent.

evolutionary biology↗

bioRxiv2024

Time-dependent effects of species interactions at macroevolutionary scale shape the diversity of mimetic butterflies.

Evidence that species interactions can affect macroevolutionary dynamics of trait and species diversification is scarce. Mutualistic Mullerian mimicry is a compelling example of example of ecological interactions that has been shown to drive evolutionary convergence, Here, we test how mutualistic Mullerian mimicry shapes macroevolutionary patterns of diversification in the Ithomiini butterflies. We show that the age of color patterns is the primary determinant of species richness within mimicry rings but not phylogenetic diversity. We find pervasive phylogenetic signal in mimicry rings and in color patterns associated within polymorphic species. Only a small set of mimicry rings show high phylogenetic diversity. We identify patterns of saturation in the accumulation of new mimicry rings and in the number of evolutionary convergences towards the most species-rich mimicry rings. Those saturation patterns are likely caused by niche filling along various ecological dimensions, within and among the mimetic communities living in sympatry. The time-dependent effects detected in our study illustrate how neutral processes and ecological interactions interact and shape species and phenotypic diversification.

evolutionary biology↗

bioRxiv2023

The effectiveness of pseudomagic traits in promoting premating isolation

Upon the secondary contact of populations, speciation with gene flow is greatly facilitated when the same pleiotropic loci are both subject to divergent ecological selection and induce non-random mating, leading to loci with this fortuitous combination of functions being referred to as "magic trait" loci. We use a population genetics model to examine whether "pseudomagic trait" complexes, composed of physically linked loci fulfilling these two functions, are as efficient in promoting premating isolation as magic traits. We specifically measure the evolution of choosiness, which controls the strength of assortative mating. We show that, surprisingly, pseudomagic trait complexes, and to a lesser extent also physically unlinked loci, can lead to the evolution of considerably stronger assortative mating preferences than do magic traits, provided polymorphism at the involved loci is maintained. This is because assortative mating preferences are generally favored when there is a risk of producing maladapted recombinants, as occurs with nonmagic trait complexes but not with magic traits (since pleiotropy precludes recombination). Contrary to current belief, magic traits may not be the most effective genetic architecture for promoting strong premating isolation. Distinguishing between magic traits and pseudomagic trait complexes is therefore important when inferring their role in premating isolation. This calls for further fine-scale genomic research on speciation genes.

evolutionary biology↗

bioRxiv2021

Balancing quality and quantity of social relationships in volatile social environments

Cooperation does not occur in a vacuum: interactions develop over time in social groups that undergo demographic changes. Intuition suggests that stable social environments favour developing few but strong reciprocal relationships (a focused strategy), while volatile social environments favour the opposite: more but weaker social relationships (a diversifying strategy). We model reciprocal investments under a quality-quantity tradeoff for social relationships. We find that volatility, counterintuitively, can favour a focused strategy. This result becomes explicable through applying the theory of antagonistic pleiotropy, originally developed for senescence, to social life. Diversifying strategies show superior performance later in life, but with costs paid at young ages while the social network is slowly being built. Under volatile environments, many individuals die before reaching sufficiently old ages to reap the benefits. Social strategies that do well early in life are then favoured: a focused strategy leads individuals to form their first few social bonds quickly and to make strong use of existing bonds. Our model highlights the importance of pleiotropy and population age structure for the evolution of cooperative strategies and other social traits, and shows that it is not sufficient to reflect on the fate of survivors only, when evaluating the benefits of social strategies.

evolutionary biology↗

bioRxiv2020

Costly mate preferences can promote reproductive isolation along ecological gradients

Species often replace each other spatially along contact zones, giving scope for parapatric speciation. In models of parapatric speciation driven by assortative mating, costs of female choosiness have so far be ignored. Yet, if females encounter only a limited number of males, those that are too choosy may remain unmated, and this should create direct sexual selection against choosiness. In our individual-based model of parapatric ecological speciation, disruptive viability selection leads to divergence of an ecological trait. Additionally, female choosiness (following a matching mating rule based on the same ecological trait) can evolve at the risk of remaining unmated, and can limit gene flow between diverging populations. In line with previous litterature, out of the contact zone, the evolution of cost-free choosiness stops at intermediate values due to indirect selection against strong choosiness. Here we show that a weak cost of choosiness, by modifying genotypic frequencies on which viability selection acts, reduces this selection pressure, thus permitting the evolution of stronger choosiness than in the absence of costs. In strong contrast to sympatric models, costs of choosiness can therefore promote reproductive isolation in parapatry.

evolutionary biology↗

bioRxiv2020

Transmissible cancers do not easily select for sexual reproduction

The predominance of sexual reproduction in eukaryotes remains paradoxical in evolutionary theory. Of the hypotheses proposed to resolve this paradox, the "Red Queen hypothesis" emphasizes the potential of antagonistic interactions to cause fluctuating selection, which favours the evolution and maintenance of sex. While empirical and theoretical developments have focused on host-parasite interactions, the premises of the Red Queen theory apply equally well to any type of antagonistic interactions. Recently, it has been suggested that early multicellular organisms with basic anticancer defenses were presumably plagued by antagonistic interactions with transmissible cancers, and that this could have played a pivotal role in the evolution of sex. Here, we dissect this argument using a population genetic model. One fundamental aspect distinguishing transmissible cancers from other parasites is the continual production of cancerous cell lines from hosts own tissues. We show that this influx dampens fluctuating selection and therefore makes the evolution of sex more difficult than in standard Red Queen models. Although coevolutionary cycling can remain sufficient to select for sex under some parameter regions of our model, we show that the size of those regions shrinks once we account for epidemiological constraints. Altogether, our results suggest that horizontal transmission of cancerous cells is unlikely to cause fluctuating selection favouring sexual reproduction. Nonetheless, we confirm that vertical transmission of cancerous cells can promote the evolution of sex through a separate mechanism, known as similarity selection, that does not depend on coevolutionary fluctuations.

evolutionary biology↗

bioRxiv2019

Evolution of conspicuousness in defended species involved in Mullerian mimicry

Variation in the conspicuousness of colour patterns is observed within and among defended prey species. The evolution of conspicuous colour pattern in defended species can be strongly impaired because of increased detectability by predators. Nevertheless, such evolution of the colour pattern can be favoured if changes in conspicuousness result in Mullerian mimicry with other defended prey. Here, we develop a model describing the population dynamics of a conspicuous defended prey species, and we assess the invasion conditions of derived phenotypes that differ from the ancestral phenotype by their conspicuousness. Such change in conspicuousness may then modify their level of mimicry with the local community of defended species. Derived colour pattern displayed in this focal population can therefore be either exactly similar, partially resembling or completely dissimilar to the local mimicry ring displaying the ancestral colour pattern. We assume that predation risk depends (1) on the number of individuals sharing a given colour pattern within the population, (2) on the occurrence of co-mimetic defended species, and (3) on the availability of alternative edible prey. Using a combination of analytical derivations and numerical simulations, we show that less conspicuous colour patterns are generally favoured within mimicry rings, unless reduced conspicuousness impairs mimicry. By contrast, when a mutation affecting the colour pattern leads to a shift toward a better protected mimicry ring, crypsis is no longer necessarily beneficial and a more conspicuous colour pattern can be favoured. The selected aposematic pattern then depends on the local composition of mimetic communities, as well as on the detectability, memorability and level of mimicry of the colour patterns.

evolutionary biology↗

bioRxiv2018

Coevolution of male and female mate choice can hamper speciation

Sexual interactions play an important role in the evolution of reproductive isolation, with important consequences for speciation. Theoretical studies have focused on the evolution of mate preferences in each sex separately. However, mounting empirical evidence suggests that premating isolation often involves mutual mate choice. Here, using a population genetic model, we investigate how female and male mate choice coevolve under a phenotype matching rule and how this affects reproductive isolation. We show that the evolution of female preferences increases the mating success of males with reciprocal preferences, favouring mutual mate choice. However, the evolution of male preferences weakens indirect selection on female preferences and, with weak genetic drift, the coevolution of female and male mate choice leads to periodic episodes of random mating with increased hybridization (deterministic preference cycling triggered by stochasticity). Thus, counterintuitively, the process of establishing premating isolation proves rather fragile if both male and female mate choice contribute to assortative mating.

evolutionary biology↗