Etienne Danchin

• PhD
• DRCE at French National Centre for Scientific Research

Among species reproducing sexually, mating strategies represent a major component of individual fitness. The Major Histocompatibility Complex (MHC) is an extremely diverse set of genes responsible for immunological recognition and defence against pathogens. Although MHC dissimilarity between mates has been proposed to drive mate choice through incr...

Long-term social memory (LTSM) is a key feature to elicit the cultural inheritance of behaviour independently of genetics. However, the neurobiological basis of LTSM remains largely unknown. We previously used the Drosophila animal model, which is known to perform mate copying through observational learning of the mate choice of conspecifics to sho...

Mate choice is a crucial decision in any animal. In terms of fitness, the best mate is the one that leads to the most abundant and productive offspring. Pairing with a low-quality mate would reduce fitness, generating selection for accurate and subtle mate choice in all animal species. Hence, mate choice is expected to be highly context dependent,...

Social learning is learning from the observation of how others interact with the environment. However, in nature, individuals often need to process serial social information and may favour either the most recent information (recency bias), constantly updating knowledge to match the environment, or the information that appeared first in the series (...

This handbook is currently in development, with individual articles publishing online in advance of print publication. At this time, we cannot add information about unpublished articles in this handbook, however the table of contents will continue to grow as additional articles pass through the review process and are added to the site. Please note...

Mate choice constitutes a major fitness-affecting decision often involving social learning leading to copying the preference of other individuals (i.e., mate copying). While mate copying exists in many taxa, its underlying neurobiological mechanisms remain virtually unknown. Here, we show in Drosophila melanogaster that the rutabaga gene is necessa...

After reviewing the evidence that led many evolutionary biologists to highlight the necessity to have the Modern Synthesis of Evolution evolve towards a new more integrative framework, I discuss characteristics that should prevail in this endeavour. I sketch a pathway towards the new synthesis by building the new synthesis around inheritance mechan...

The zebrafish Danio rerio is an important model organism, but little is known about its mating preferences and how these are influenced by personality traits like boldness. In this study, we tested two strains of zebrafish and addressed whether females used social information to build a mating preference, a behavior called mate copying, and whether...

Although the environment is three-dimensional (3-D), humans are able to extract subtle information from two-dimensional (2-D) images, particularly in the domain of sex. However, whether animals with simpler nervous systems are capable of such information extraction remains to be demonstrated, as this ability would suggest a functional generalisatio...

Although conformity as a major driver for human cultural evolution is a well‐accepted and intensely studied phenomenon, its importance for non‐human animal culture has been largely overlooked until recently. This limited for decades the possibility of studying the roots of human culture. Here, we provide a historical review of the study of conformi...

Acceptance and avoidance can be socially transmitted, especially in the case of mate choice. When a Drosophila melanogaster female observes a conspecific female (called demonstrator female) choosing to mate with one of two males, the former female (called observer female) can memorize and copy the latter female’s choice. Traditionally in mate-copyi...

High levels of within-population behavioural variation can have drastic demographic consequences, thus changing the evolutionary fate of populations. A major source of within-population heterogeneity is personality. Nonetheless, it is still relatively rarely accounted for in social learning studies that constitute the most basic process of cultural...

After being coined by Conrad Waddington in the context of development, today the term epigenetics focuses on the molecular machinery beyond genes. Epigenetics is central to early in life effects and their consequences in eco-evolutionary dynamics. I review the two historical understandings of epigenetics, i.e. its Developmental and Evolutionary und...

Theory predicts that parental heritable characteristics should shape sex allocation decisions when their effects on reproduction or survival are offspring sex-dependent. Numerous studies have questioned to what extent characteristics displayed by one of the parents matched theoretical expectations. This contrasts with the handful of studies that in...

Cultural evolution requires the social transmission of information. For this reason, scholars have emphasized social learning when explaining how and why culture evolves. Yet cultural evolution results from many mechanisms operating in concert. Here, we argue that the emphasis on social learning has distracted scholars from appreciating both the fu...

A good overlap between offspring energetic requirements and availability of resources is required for successful reproduction. Accordingly, individuals from numerous species fine-tune their timing of breeding by integrating cues that predict environmental conditions during the offspring period. Besides acquiring information from their direct intera...

We describe here a protocol for the generation of sequence-ready libraries for population epigenomics studies, and the analysis of alignment results. We show that the protocol can be used to monitor chromatin structure changes in populations when exposed to environmental cues. The protocol is a streamlined version of the Assay for transposase acces...

Genes of the major histocompatibility complex (MHC) play a pivotal role in parasite resistance, and their allelic diversity has been associated with fitness variations in several taxa. However, studies report inconsistencies in the direction of this association, with either positive, quadratic or no association being described. These discrepancies...

Background: This study therefore describes the classical experimental system postulated by Richard Woltereck 100 years ago: the adaptive morphological phenotypic plasticity of daphnia . Phenotypic plasticity is an important feature of biological systems that is likely to play a major role in the adaptation of organisms exposed to an environmental s...

Trophic cascades – the indirect effect of predators on non‐adjacent lower trophic levels – are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underlying e...

The discovery of the multidimensional nature of the inherited information carried by the epigenome and the characterization of its intra‐ and intergenerational dynamics have profoundly changed our understanding of the functioning of biological organisms and the origins of phenotypic diversity. This has raised considerable interest in the study of e...

Phenotypic plasticity is an important feature of biological systems that is likely to play a major role in the future adaptation of organisms to the ongoing global changes. It may allow an organism to produce alternative phenotypes in responses to environmental cues. Modifications in the phenotype can be reversible but are sometimes enduring and ca...

Thornquist and Crickmore claim that systematic experimental error may explain the results of Danchin and colleagues. Their claim rests on mistakes in their analyses, for which we provide corrections. We reassert that conformity in fruitflies predicts long-lasting mate-preference traditions.

Carotenoid-based ornaments are common signaling features in animals. Although the mechanisms that link color-based signals to individual condition is key to understanding the evolution and function of these ornaments, they are most often poorly known. Several hypotheses have been posited. They include (i) the role of foraging abilities on carotenoi...

Inbreeding, i.e. the mating of genetically related individuals, can lead to reduced fitness and is considered to be a major selective force of mate choice. Although inbreeding avoidance has been found in numerous taxa, individuals may face constraints when pairing, leading to mating with suboptimal partners. In such circumstances, individuals that...

Inbreeding, i.e. the mating of genetically related individuals, can lead to reduced fitness and is considered to be a major selective force of mate choice. Although inbreeding avoidance has been found in numerous taxa, individuals may face constraints when pairing, leading to mating with suboptimal partners. In such circumstances, individuals that...

A bstract Trophic cascades—the indirect effect of predators on non-adjacent lower trophic levels—are important drivers of the structure and dynamics of ecological communities. However, the influence of intraspecific trait variation on the strength of trophic cascade remains largely unexplored, which limits our understanding of the mechanisms underl...

Phenotypic plasticity is a ubiquitous process found in all living organisms. Polyphenism is an extreme case of phenotypic plasticity which shares a common scheme in insects such as honeybees, locusts or aphids: an initial perception of environmental stimuli, a neuroendocrine transmission of these signals to the target tissues, the activation of epi...

The role of intraspecific variation in the magnitude and direction of plastic responses in ecology and evolution is increasingly recognized. However, the factors underlying intraspecific variation in plastic responses remain largely unexplored, particularly for the hypothesis that the herbivores’ phenotypic response to predators might vary amongst...

Sex allocation studies among birds and mammals are notoriously inconsistent with theoretical predictions. One explanation is the difficulty of collecting data on costs and benefits of sex-ratio adjustments, which prevents the investigation of underlying assumptions. Some predictions may thus have been tested in species where they should not have be...

Sexually transmitted infections (STIs) in animals may have profound eco-evolutionary consequences, yet experimental studies of the sexual transmission of pathogens in wild populations are lacking. Here to identify sexually transmitted bacteria, we experimentally manipulated ejaculate transfer in black-legged kittiwakes (Rissa tridactyla) by blockin...

Recent discoveries show that early in life effects often have long-lasting influences, sometimes even spanning several generations. Such intergenerational effects of early life events appear not easily reconcilable with strict genetic inheritance. However, an integrative evolutionary medicine of early life effects needs a sound view of inheritance...

Table S1. A description of published models of non‐genetic inheritance and genetic assimilation. Table S2. Description of the model parameters.

Mate-copying is a form of social learning in which the mate-choice decision of an individual (often a female) is influenced by the mate-choice of conspecifics. Drosophila melanogaster females are known to perform such social learning, and in particular, to mate-copy after a single observation of one conspecific female mating with a male of one phen...

Trendsetting flies Though once believed to be confined to humans, culture has now been demonstrated in many different animal species, from whales to parrots. Most such animals have high levels of cognition, but the basics of transmission and copying could easily occur in less cognitively advanced species. Danchin et al. show that mating culture can...

L’épigénétique, à savoir l’ensemble des modifications héritables étroitement liées au génome mais sans être basées sur des modifications de séquences de l’ADN, a émergé ces dernières années comme une discipline incontournable pour la compréhension des processus biologiques. Les avancées considérables des techniques de séquençage permettent aujourd’...

After decades of debate about the existence of non‐genetic inheritance, the focus is now slowly shifting towards dissecting its underlying mechanisms. Here, we propose a new mechanism that, by integrating non‐genetic and genetic inheritance, may help build the long‐sought inclusive vision of evolution. After briefly reviewing the wealth of evidence...

Mate-copying is a form of social learning in which witnessing sexual interactions between conspecifics biases an observer individual's future mate-choice. Mate-copying exists in many vertebrates, as well as in Drosophila melanogaster. Here, we show that female fruit flies can copy the choice for mutant males (Curly-wing [Cy] mutants vs. wild types...

Transgenerational phenotypic plasticity is a fast non-genetic response to environmental modifications that can buffer the effects of environmental stresses on populations. However, little is known about the evolution of plasticity in the absence of standing genetic variation although several non-genetic inheritance mechanisms have now been identifi...

Aggregation during diapause is a common phenomenon in arthropods that nevertheless remains poorly understood. The most commonly claimed benefit is that survival is higher in aggregations but animal aggregations could also be driven by sexual selection. In this perspective, we investigated whether aggregations in insects could be part of their matin...

To assess potential mates' quality individuals can observe sexually interacting conspecifics. Such social information use is called mate copying and occurs when observer individuals witnessing sexual interactions of conspecifics later show a mating preference for mates that were seen mating. Most studies have focused on female mate copying, as fema...

Although there are many examples of contemporary directional selection, evidence for responses to selection that match predictions are often missing in quantitative genetic studies of wild populations. This is despite the presence of genetic variation and selection pressures - theoretical prerequisites for the response to selection. This conundrum...

In many sexually reproducing species, individuals can gather information about potential mates by observing their mating success. This behavioural pattern, that we call mate-copying, was reported in the fruit fly Drosophila melanogaster where females choosing between two males of contrasting phenotypes can build a preference for males of the phenot...

Breeding habitat selection is strongly influenced by social information, which is that extracted from the behaviour and performance of other individuals. Also, signals shaped by selection to convey information may be used by unintended receivers as a particular form of social information that has been neglected in a breeding habitat selection conte...

Individuals must trade‐off between energetically costly activities to maximize their fitness. However, the underlying physiological mechanism remains elusive. Oxidative stress, the imbalance between reactive oxygen species production and antioxidant and/or repair activities, has been suggested to underlie life‐history trade‐offs: greater investment...

Mate choice can strongly affect fitness in sexually reproducing organisms. A form of mate choice is mate copying, in which individuals use information about potential mates by copying the mate choice of other individuals. While many studies have documented mate copying, little is known about the effect of environmental conditions on this behaviour....

Maternal effects occur when the mother’s phenotype influences her offspring’s phenotype. In birds, differential allocation in egg yolk components can allow mothers to compensate for the competitive disadvantage of junior chicks. We hypothesise that the parent-older chick conflict peaks at intermediate conditions: parents benefit from the younger ch...

Table S1. Summary of the linear mixed models and linear models describing variation in growth rate and mass gain in the first 10 days in senior chicks (N = 39) and junior chicks (N = 39, outlier included), respectively. Table S2. Summary of the linear models describing variation in maximum weight in senior chicks (N = 33) and junior chicks (N = 33...

Understanding how organisms cope with global change is a major scientific challenge. The molecular pathways underlying rapid adaptive phenotypic responses to global change remain poorly understood. Here, we highlight the relevance of two environment-sensitive molecular elements: transposable elements (TEs) and epigenetic components (ECs). We first...

We confront the neo-Darwinian core tenet of blind variation, or random mutation, with classical and recent models of genetic assimilation. We first argue that all the mechanisms proposed so far rely on blind genetic variation fuelling natural selection. Then, we examine a new hypothetical mechanism of genetic assimilation, relying on non-blind gene...

Carotenoid-based integument coloration is extremely widespread in animals and commonly used as an honest signal of condition in sexual selection. Besides being used for color expression, carotenoids have antioxidant and immunomodulatory activity. Being a limited resource, carotenoid allocation to competing demands generates a trade-off. Recent stud...

In Danchin & Pocheville (2014), we urged that physiology and evolution be better integrated, as it is more and more apparent that they represent two facets of a single biological process. The first reason for this integration is somehow classical but still essential. Physiology is central in determining the selective value of organisms, and thus th...

Sex allocation theory predicts that parents should bias offspring sex according to the costs and benefits associated with producing either sex in a given context. Accurately interpreting sex-ratio biases, therefore, requires a precise identification of these selective pressures. However, such information is generally lacking. This may partly explai...

Animals are known to select mates to maximize the genetic diversity of their offspring in order to achieve immunity against a broader range of pathogens. Although several bird species preferentially mate with partners that are dissimilar at the major histocompatibility complex (MHC), it remains unknown whether they can use olfactory cues to assess...

Physiology and evolutionary biology have developed as two separated disciplines, a separation that mirrored the hypothesis that the physiological and evolutionary processes could be decoupled. We argue that non-genetic inheritance shatters the frontier between physiology and evolution, and leads to the coupling of physiological and evolutionary pro...

In many circumstances, heritability estimates are subject to two potentially interacting pitfalls: the spatial and the regression to the mean (RTM) fallacies. The spatial fallacy occurs when the set of potential movement options differs among individuals according to where individuals depart. The RTM fallacy occurs when extreme measurements are fol...

In unpredictable environments, any tactic that enables avian parents to adjust brood size and, thus, energy expenditure to environmental conditions should be favoured. Hatching asynchrony (HA), which occurs whenever incubation commences before clutch completion, may comprise such a tactic. For instance, the sibling rivalry hypothesis states that th...

Fluctuating asymmetry has been suggested to be a phenotypic marker of developmental stability and is often seen as an indicator of overall quality. However, its role in sexual selection has been debated. To determine the potential role of black wingtip asymmetry in sexual selection in Black-legged Kittiwakes (Rissa tridactyla), we investigated whet...

Transgenerational sources of biological variation have been at the center of evolutionary studies ever since Darwin and Wallace identified natural selection. This is because evolution can only operate on traits whose variation is transmitted, i.e. traits that are heritable. The discovery of genetic inheritance has led to a semantic shift, resulting...

Following the discovery that inheritance entails the interaction between genetic and nongenetic processes, biology is undergoing a profound mutation. This paradigm shift implies that the model of heredity that is emerging incorporates genetic and nongenetic processes. A way to integrate all forms of inheritance harmoniously is to consider what unif...

Background Gastrointestinal bacteria play a central role in the health of animals. The bacteria that individuals acquire as they age may therefore have profound consequences for their future fitness. However, changes in microbial community structure with host age remain poorly understood. We characterised the cloacal bacteria assemblages of chicks...

What role does non-genetic inheritance play in evolution? In recent work we have independently and collectively argued that the existence and scope of non-genetic inheritance systems, including epigenetic inheritance, niche construction/ecological inheritance, and cultural inheritance—alongside certain other theory revi-sions—necessitates an extens...

The literature is full of examples of inbreeding avoidance, while recent mathematical models predict that inbreeding tolerance or even inbreeding preference should be expected under several realistic conditions like e.g. polygyny. We investigated male and female mate preferences with respect to relatedness in the fruit fly D. melanogaster. Experime...

Semen limitation (lack of semen to fertilize all of a female's eggs) imposes high fitness costs to female partners. Females should therefore avoid mating with semen-limited males. This can be achieved by using public information extracted from watching individual males' previous copulating activities. This adaptive preference should be flexible giv...

Sex allocation theory predicts that parents should favor offspring of the sex that provides the greatest fitness return. Despite growing evidence suggesting that vertebrates are able to overcome the constraint of chromosomal sex determination, the general pattern remains equivocal, indicating a need for experimental investigations. We used an experi...