Biology subjects

LLAURENS, V.

Publications and source records attributed to LLAURENS, V..

5 recordsLinked to original sources

bioRxiv2023

Convergence in sympatric swallowtail butterflies reveals ecological interactions as a key driver of worldwide trait diversification.

Ecological interactions may fuel phenotypic diversification in sympatric species. While competition can enhance trait divergence, other ecological interactions may promote convergence in sympatric species. Within butterflies, evolutionary convergences in wing color patterns have been reported between distantly-related species, especially in females from palatable species, where mimetic color patterns are promoted by predator communities shared with defended species living in sympatry. Wing color patterns are also often involved in species recognition in butterflies, and divergence in this trait has been reported in closely-related species living in sympatry as a result of reproductive character displacement. Here we investigate the effect of sympatry between species on the convergence vs. divergence of their wing color patterns in relation to phylogenetic distance, focusing on the iconic swallowtail butterflies (family Papilionidae). We developed a new unsupervised machine-learning-based method to estimate phenotypic distances among wing color patterns from 337 species allowing to finely quantify morphological diversity at global scale within and among species, allowing to compute pairwise phenotypic distances between sympatric and allopatric species pairs. We found that sympatry promoted strong convergence, while divergence in sympatry was less frequent and weaker. The effect of sympatry on convergence was stronger on females than males, suggesting that differential selective pressures acting on the two sexes drove sexual dimorphism. Our results highlight the significant effect of ecological interactions driven by predation pressures on trait diversification in Papilionidae and evidence the interaction between phylogenetic proximity and ecological interactions in sympatry acting on macroevolutionary patterns of phenotypic diversification.

evolutionary biology↗

bioRxiv2022

How many cues are sexy? Evolution of mate preference towards multiple traits in sympatric species

Mate preferences may target traits (1) enhancing offspring adaptation and (2) reducing heterospecific matings. Because similar selective pressures are acting on traits shared by different sympatric species, preference enhancing offspring adaptation may increase heterospecific mating, in sharp contrast with the classical case of so-called magic traits. Using a mathematical model, we study which and how many traits will be used during mate choice, when preferences for locally adapted traits increase heterospecific mating. In particular, we study the evolution of preference towards an adaptive vs. a neutral trait in sympatric species. We take into account sensory trade-offs which may limit the emergence of preference for several traits. Our model highlights that the evolution of preference towards adaptive vs. neutral traits depends on the selective regimes acting on traits but also on heterospecific interactions. When the costs of heterospecific interactions are high, mate preference is likely to target neutral traits that become a reliable cue limiting heterospecific matings. We show that the evolution of preference towards a neutral trait benefits from a positive feedback loop: the more preference targets the neutral trait, the more it becomes a reliable cue for species recognition. We then reveal the key role of sensory trade-offs and the cost of choosiness favouring the evolution of preferences targeting adaptive traits, rather than traits reducing heterospecific mating. When sensory trade-offs and the cost of choosiness are low, we also show that preferences targeting multiple traits evolve, improving offspring fitness by both transmitting adapted alleles and reducing heterospecific mating. Altogether, our model aims at reconciling good gene and reinforcement models to provide general predictions on the evolution of mate preferences within natural communities. Impact SummaryMate preferences are widespread throughout the animal kingdom and generate powerful selective forces impacting the diversification of traits and species. The evolution of such preferences has been the focus of multiple theoretical and empirical studies and intense scientific debates. The evolution of mate preference (1) enhancing offspring fitness and (2) reducing heterospecific mating have been mostly studied separately, except in the specific case of preference for so-called magic traits that increase both offspring survival and species divergence. However, in many cases, the evolution of traits in sympatric species generates conflicting evolutionary forces acting on preferences. On one hand, enhanced offspring survival promotes preference towards locally adaptive traits and may thus lead to convergent evolution of traits among sympatric species. On the other hand, the evolution of similar traits in sympatric species may generate costly heterospecific sexual interactions promoting preference towards traits that diverge between species. Here, we thus build a general mathematical model to investigate the evolutionary factors determining which and how many traits are targeted by mate choice. We especially determine whether preferences will likely target adaptive vs. neutral traits. Our model highlights that the evolution of preferences for adaptive vs. neutral traits in sympatric species depends on within-species mating opportunities but also on the niche overlap between species, tuning heterospecific interactions. By jointly considering (1) the selection regimes acting on the targeted traits within species, as well as (2) interactions with other species living in sympatry, our theoretical study provides a general framework reconciling these research fields.

evolutionary biology↗

bioRxiv2021

Evolutionary origins of sexual dimorphism : Lessons from female-limited mimicry in butterflies.

The striking female-limited mimicry observed in some butterfly species is a text-book example of sexually-dimorphic trait submitted to intense natural selection. Two main evolutionary hypotheses, based on natural and sexual selection respectively, have been proposed. Predation pressure favouring mimicry toward defended species could be higher in females because of their slower flight, and thus overcome developmental constraints favouring the ancestral trait that limits the evolution of mimicry in males but not in females. Alternatively, the evolution of mimicry in males could be limited by females preference for non-mimetic males. However, the evolutionary origin of female preference for non-mimetic males remains unclear. Here, we hypothesise that costly sexual interactions between individuals from distinct sympatric species might intensify because of mimicry, therefore promoting female preference for non-mimetic trait. Using a mathematical model, we compare the evolution of female-limited mimicry when assuming either alternative selective hypotheses. We show that the patterns of divergence of male and female trait from the ancestral traits can differ between these selection regimes. We specifically highlight that divergence in females trait is not a signature of the effect of natural selection. Our results also evidence why female-limited mimicry is more frequently observed in Batesian mimics.

evolutionary biology↗

bioRxiv2020

Sex, Competition and Mimicry : an eco-evolutionary model reveals how ecological interactions shape the evolution of phenotypes in sympatry.

1Phenotypic evolution in sympatric species can be strongly impacted by species interactions, either mutualistic or antagonistic, which may favour local phenotypic divergence or convergence. Interspecific sexual interactions between sympatric species has been shown to favour phenotypic divergence of traits used as sexual cues for example. Those traits may also be involved in local adaptation or in other types of species interactions resulting in complex evolution of traits shared by sympatric species. Here we focus on mimicry and study how reproductive interference may impair phenotypic convergence between species with various levels of defences. We use a deterministic model assuming two sympatric species and where individuals can display two different warning colour patterns. This eco-evolutionary model explores how ecological interactions shape phenotypic evolution within sympatric species. We investigate the effect of (1) the opposing density-dependent selections exerted on colour patterns by predation and reproductive behaviour, and (2) the impact of relative species and phenotype abundances on the fitness costs faced by each individual depending on their species and phenotype. Our model shows that reproductive interference may limit the convergent effect of mimetic interactions and may promote phenotypic divergence between Mullerian mimics. The divergent and convergent evolution of traits also strongly depends on the relative species and phenotype abundances and levels of trophic competition, highlighting how the eco-evolutionary feedbacks between phenotypic evolution and species abundances may result in strikingly different evolutionary routes.

evolutionary biology↗

bioRxiv2020

Convergence in sympatry: evolution of blue-banded wing pattern in Morpho butterflies

Species interactions such as mimicry can promote trait convergence but disentangling this effect from those of shared ecology, evolutionary history and niche conservatism is often challenging. Here by focusing on wing color pattern variation within and between three butterfly species living in sympatry in a large proportion of their range, we tested the effect of species interactions on trait diversification. These butterflies display a conspicuous iridescent blue coloration on the dorsal side of their wings and a cryptic brownish colour on the ventral side. Combined with an erratic and fast flight, these color patterns increase the difficulty of capture by predators and contribute to the high escape abilities of these butterflies. We hypothesize that, beyond their direct contribution to predator escape, these wing patterns can be used as signals of escape abilities by predators, resulting in positive frequency-dependent selection favouring convergence in wing pattern in sympatry. To test this hypothesis, we quantified dorsal wing pattern variations of 723 butterflies from the three species sampled throughout their distribution, including sympatric and allopatric situations and compared the phenotypic distances between species, sex and localities. We detected a significant effect of localities on colour pattern, and higher inter-specific resemblance in sympatry as compared to allopatry, consistent with the hypothesis of local convergence of wing patterns. Our results provide some support to the existence of escape mimicry in the wild and stress the importance of estimating trait variation within species to understand trait variation between species, and to a larger extent, trait diversification at the macro-evolutionary scale.

evolutionary biology↗