Pim Edelaar | Universidad Pablo de Olavide (original) (raw)

Papers by Pim Edelaar

Adaptive divergence has long been a core topic in the field of evolutionary biology, with natural... more Adaptive divergence has long been a core topic in the field of evolutionary biology, with natural selection traditionally considered its only driver. Here we focus on the ability of matching habitat choice to generate population divergence and reproductive isolation. This alternative mechanism of divergence considers that individuals choose their habitats based on an evaluation of the ecological match between their phenotype and the available environments, which subsequently limits gene flow. To test this, we conducted experiments with captive zebra fiches equipped with transponder-tags and using transponder-operated bird feeders. We thereby created within a single aviary two areas with distinct resources, and the associated ecological traits that provided access to only one of the resources. We found that most zebra finches chose to breed in the same area as where they had access to their ecological resource, thereby creating population divergence in the absence of current natural selection on the ecological trait. This choice of breeding area indirectly resulted in assortative mating for the ecological trait. If the ecological trait were heritable, this assortative mating would carry the obtained divergence into the next generation. Our results experimentally confirm the predicted ability of matching habitat choice to drive rapid population divergence and limit maladaptive gene flow, especially at the small temporal and spatial scales where natural selection is unlikely to do so (here: one generation and one aviary). This might be increasingly relevant in a world where anthropogenic impacts create rapid environmental changes. Species face unprecedented environmental challenges due to human activities rapidly altering habitats and biological communities. Understanding how species adapt is therefore crucial for conservation of endangered species and management of invasive species. Natural selection, the cornerstone of adaptive evolution, has long been considered the only driver of adaptation to the environment. Our study delves into an intriguing alternative driver called Matching Habitat Choice (MHC), where animals select their environments based on their evaluation of how well their traits match ecologically with the available local environments. Using captive zebra finches in an aviary, our research examined how these birds make choices about where to settle and breed in relation to locally available food resources. We observed that these birds preferred breeding sites matching their ecological traits. We therefore confirmed that population divergence is possible without current natural selection. Our findings carry significant implications for biodiversity management amidst rapid environmental changes. They underscore the power of individual decision-making in shaping evolutionary dynamics, offering insights for ways to preserve species in an ever-changing world.

It is a tenet of evolutionary biology that local adaptation is driven by natural selection, while... more It is a tenet of evolutionary biology that local adaptation is driven by natural selection, while it is hindered by gene flow. This is because random movements between populations disrupt the match between phenotype and the local environment. However, if individuals moved to the environments where they have higher ecological performance, movements between populations could facilitate local adaptation. Here we show that movements of individuals towards their phenotype-dependent optimal breeding areas rapidly result in adaptive population divergence. We manipulated local ecological performance in a wild population of Eurasian tree sparrows by creating an artificial ecological trait that gave differential access to a new food source. Individuals exhibited a very strong preference for the breeding sites where they had the highest ecological performance. This promoted higher reproductive success, local adaptation, assortative mating, and reproductive isolation with respect to the novel trait. Our results experimentally show how local adaptation can be achieved by directed movements of individuals, if they settle in the environment to which they are best adapted. Considering this mechanism of adaptation will improve our understanding of how populations and species adapt and diverge. This may be especially relevant for biodiversity management under global change, where organisms face rapid and novel environmental changes.

Over the last few years, matching habitat choice has gained attention as a mechanism for maintain... more Over the last few years, matching habitat choice has gained attention as a mechanism for maintaining biodiversity and driving speciation. It revolves around the idea that individuals select the habitat in which they perceive to obtain greater fitness after a prior evaluation of their local performance across heterogeneous environments. This results in individuals with similar ecological traits converging to the same patches, and hence could indirectly cause assortative mating when mating occurs in those patches. White-eyed mutants of Drosophila fruit flies have a series of disadvantages compared to wild type flies, including a poorer performance under bright light. It has been previously reported that, when given a choice, wild type Drosophila simulans preferred a brightly lit habitat while white-eyed mutants occupied a dimly lit one. This spatial segregation allowed the eye color polymorphism to be maintained for several generations, whereas normally it is quickly replaced by the wild type. Here we compare the habitat choice decisions of white-eyed and wild type flies in another species, D. melanogaster. We released groups of flies in a light gradient and recorded their departure and settlement behavior. Departure depended on sex and phenotype, but not on the light conditions of the release point. Settlement depended on sex, and on the interaction between phenotype and light conditions of the point of settlement. Nonetheless, simulations showed that this differential habitat use by the phenotypes would only cause a minimal degree of assortative mating in this species.

habitat saturation 13 2. Methods 16 2.1. Study populations 16 2.2. Warbler census and territory m... more habitat saturation 13 2. Methods 16 2.1. Study populations 16 2.2. Warbler census and territory mapping 16 2.3. Moultscores 2.4. Breeding observations 2.5. Feeding observations 2.6. Blood sampling and analyses of blood samples 2.7. Historical data .

Datasets, Nov 6, 2019

The numbers and impacts of non-native species (NNS) continue to grow. Multiple ranking protocols ... more The numbers and impacts of non-native species (NNS) continue to grow. Multiple ranking protocols have been developed to identify and manage the most damaging species. However, existing protocols differ considerably in the type of impact they consider, the way evidence of impacts is included and scored, and in the way the precautionary principle is applied. These differences may lead to inconsistent impact assessments. Since these protocols are considered a main policy tool to promote mitigation efforts, such inconsistencies are undesirable, as they can affect our ability to reliably identify the most damaging NNS, and can erode public support for NNS management. Here we propose a broadly applicable framework for building a transparent NNS impact evidence base. First, we advise to separate the collection of evidence of impacts from the act of scoring the severity of these impacts. Second, we propose to map the collected evidence along a set of distinguishing criteria: where it is published, which methodological approach was used to obtain it, the relevance of the geographical area from which it originates, and the direction of the impact. This procedure produces a transparent and reproducible evidence base which can subsequently be used for different scoring protocols, and which should be made public. Finally, we argue that the precautionary principle should only be used at the risk management stage. Conditional upon the evidence presented in an impact assessment, decision-makers may use the precautionary principle for NNS management under scientific uncertainty regarding the likelihood and magnitude of NNS impacts. Our framework paves the way for an improved application of impact assessments protocols, reducing inconsistencies and ultimately enabling more effective NNS management.Universidad Pablo de Olavide de Sevilla. Departamento de Biología Molecular e Ingeniería Bioquímic

PLOS ONE, Oct 15, 2020

Matching habitat choice is gaining attention as a mechanism for maintaining biodiversity and driv... more Matching habitat choice is gaining attention as a mechanism for maintaining biodiversity and driving speciation. It revolves around the idea that individuals select the habitat in which they perceive to obtain greater fitness based on a prior evaluation of their local performance across heterogeneous environments. This results in individuals with similar ecologically relevant traits converging to the same patches, and hence it could indirectly cause assortative mating when mating occurs in those patches. White-eyed mutants of Drosophila fruit flies have a series of disadvantages compared to wild type flies, including a poorer performance under bright light. It has been previously reported that, when given a choice, wild type Drosophila simulans preferred a brightly lit habitat while white-eyed mutants occupied a dimly lit one. This spatial segregation allowed the eye color polymorphism to be maintained for several generations, whereas normally it is quickly replaced by the wild type. Here we compare the habitat choice decisions of white-eyed and wild type flies in another species, D. melanogaster. We released groups of flies in a light gradient and recorded their departure and settlement behavior. Departure depended on sex and phenotype, but not on the light conditions of the release point. Settlement depended on sex, and on the interaction between phenotype and light conditions of the point of settlement. Nonetheless, simulations showed that this differential habitat use by the phenotypes would only cause a minimal degree of assortative mating in this species.

The data file lists genotypes, behavioural phenotypes and relevant cofactors of the Spanish and P... more The data file lists genotypes, behavioural phenotypes and relevant cofactors of the Spanish and Portuguese study populations of Yellow-crowned bishops (Euplectes afer). Euplectes_afer_genotypes_phenotypes.txt Publicado anteriormente en Dryad https://doi.org/10.5061/dryad.589t0It has been suggested that individual behavioural traits influence the potential to successfully colonize new areas. Identifying the genetic basis of behavioural variation in invasive species thus represents an important step towards understanding the evolutionary potential of the invader. Here, we sequenced a candidate region for neophilic/neophobic and activity behaviour - the complete exon 3 of the DRD4 gene - in 100 Yellow-crowned bishops (Euplectes afer) from two invasive populations in Spain and Portugal. The same birds were scored twice for activity behaviour while exposed to novel objects (battery or slice of apple) in captivity. Response to novel objects was repeatable (r = 0.41) within individuals. We identified two synonymous DRD4 SNPs that explained on average between 11% and 15% of the phenotypic variance in both populations, indicating a clear genetic component to the neophilic/neophobic/activity personality axis in this species. This consistently high estimated effect size was mainly due to the repeated measurement design, which excludes part of the within-individual nongenetic variance in the response to different novel objects. We suggest that the alternative alleles of these SNPs are likely introduced from the original population and maintained by weak or antagonistic selection during different stages of the invasion process. The identified genetic variants have not only the potential to serve as genetic markers of the neophobic/neophilic/activity personality axis, but may also help to understand the evolution of behaviour in these invasive bird populations.Universidad Pablo de Olavide de Sevilla. Departamento de Sistemas Físicos, Químicos y Naturale

Trends in Ecology and Evolution, May 1, 2019

Natural selection results in adaptation for populations, not individuals. Yet environmental chang... more Natural selection results in adaptation for populations, not individuals. Yet environmental change can reduce the expected fitness of an individual. Selection will favor the evolution of traits that allow individuals to proactively compensate for such reduced fitness. Although several well-known processes can achieve this goal, they are still often neglected and often not clearly distinguished. To facilitate greater attention to the full range of processes by which individuals can increase their fitness, we present a classification scheme that integrates these: phenotypic change, selection of the environment, and adjustment of the environment. We outline how these individual-level processes relate to natural selection and population-level fitness. This framework may help to guide research (and teaching) about how individuals and populations may respond to environmental change.

Ibis, Apr 23, 2020

This article is protected by copyright. All rights reserved Crossbills (Loxia spp) provide a clas... more This article is protected by copyright. All rights reserved Crossbills (Loxia spp) provide a classical avian model of ecological specialization on food resources. Previous studies have suggested that morphometric, genetic and vocal diversification among Common Crossbill L. curvirostra populations is better explained by ecological distance (use of different conifers) than by geographical distance, indicating that populations have diverged adaptatively. We tested for adaptive divergence in Iberian crossbills using bill and body size measurements of 6,082 crossbills from 27 sites each comprised of a dominant or single pine (Pinus) out of four possible species. Crossbills using different pines differed significantly in body size and bill size and shape. There was no correlation between geographic and morphological distance among sampling sites, consistent with the hypothesis that the morphological divergence of Iberian crossbills is shaped by their ecological differences (foraging on alternative conifers) rather than geographic distance. However, for unknown reasons, Common Crossbills foraging on P. sylvestris in Iberia have on average much smaller bills than Parrot Crossbills L. pytyopsittacus feeding on the same pine species northern Europe. The extent to which crossbills specialise on Iberian P. sylvestris remains to be established. Specialisation on conifers with overlapping geographic distributions may be facilitated by matching habitat choice of crossbills as a function of their local intake rates.

Biological Reviews, Oct 12, 2022

ABSTRACTEvolutionary theory has made large impacts on our understanding and management of the wor... more ABSTRACTEvolutionary theory has made large impacts on our understanding and management of the world, in part because it has been able to incorporate new data and new insights successfully. Nonetheless, there is currently a tension between certain biological phenomena and mainstream evolutionary theory. For example, how does the inheritance of molecular epigenetic changes fit into mainstream evolutionary theory? Is niche construction an evolutionary process? Is local adaptation via habitat choice also adaptive evolution? These examples suggest there is scope (and perhaps even a need) to broaden our views on evolution. We identify three aspects whose incorporation into a single framework would enable a more generalised approach to the understanding and study of adaptive evolution: (i) a broadened view of extended phenotypes; (ii) that traits can respond to each other; and (iii) that inheritance can be non‐genetic. We use causal modelling to integrate these three aspects with established views on the variables and mechanisms that drive and allow for adaptive evolution. Our causal model identifies natural selection and non‐genetic inheritance of adaptive parental responses as two complementary yet distinct and independent drivers of adaptive evolution. Both drivers are compatible with the Price equation; specifically, non‐genetic inheritance of parental responses is captured by an often‐neglected component of the Price equation. Our causal model is general and simplified, but can be adjusted flexibly in terms of variables and causal connections, depending on the research question and/or biological system. By revisiting the three examples given above, we show how to use it as a heuristic tool to clarify conceptual issues and to help design empirical research. In contrast to a gene‐centric view defining evolution only in terms of genetic change, our generalised approach allows us to see evolution as a change in the whole causal structure, consisting not just of genetic but also of phenotypic and environmental variables.

Molecular Ecology Resources, Nov 20, 2017

PCR is a universal tool for the multiplication of specific DNA sequences. For example, PCR-based ... more PCR is a universal tool for the multiplication of specific DNA sequences. For example, PCR-based sex determination is widely used, and a diversity of primer sets is available. However, this protocol requires thermal cycling and electrophoresis so results are typically obtained in laboratories and several days after sampling. Loop-mediated isothermal amplification (LAMP) is an alternative to PCR that can take molecular ecology outside the laboratory. Although its application has been successfully probed for sex determination in three species of a single avian Family (Raptors, Accipitridae), its generality remains untested and suitable primers across taxa are lacking. We designed and tested the first LAMP-based primer set for sex determination across the Modern birds (NEO-W) based on a fragment of the gene Chromo-Helicase-DNA binding protein located on the female-specific W-chromosome. Since nucleotide identity is expected to increase among more related taxa, taxonomically targeted primers were also developed for the Order Falconiformes and Families Psittacidae, Ciconiidae, Estrildidae and Icteridae as examples. NEO-W successfully determined sex in a subset of 21 species within 17 Families and 10 Orders and is therefore a candidate primer for all Modern birds. Primer sets designed specifically for the selected taxa correctly assigned sex to the evaluated species. A short troubleshooting guide for new LAMP users is provided to identify false negatives and optimize LAMP reactions. This study represents the crucial next step towards the use of LAMP for molecular sex determination in birds and other applications in molecular ecology.

Methods in Ecology and Evolution, Mar 23, 2023

Estimating the genetic variation underpinning a trait is crucial to understanding and predicting ... more Estimating the genetic variation underpinning a trait is crucial to understanding and predicting its evolution. A key statistical tool to estimate this variation is the animal model. Typically, the environment is modelled as an external variable independent of the organism, affecting the focal phenotypic trait via phenotypic plasticity. We studied what happens if the environment is not independent of the organism because it chooses or adjusts its environment, potentially creating non‐zero genotype–environment correlations. We simulated a set of biological scenarios assuming the presence or absence of a genetic basis for a focal phenotypic trait and/or the focal environment (treated as an extended phenotype), as well as phenotypic plasticity (the effect of the environment on the phenotypic trait) and/or ‘environmental plasticity’ (the effect of the phenotypic trait on the local environment). We then estimated the additive genetic variance of the phenotypic trait and/or the environment by applying five animal models which differed in which variables were fitted as the dependent variable and which covariates were included. We show that animal models can estimate the additive genetic variance of the local environment (i.e. the extended phenotype) and can detect environmental plasticity. We show that when the focal environment has a genetic basis, the additive genetic variance of a phenotypic trait increases if there is phenotypic plasticity. We also show that phenotypic plasticity can be mistakenly inferred to exist when it is actually absent and instead environmental plasticity is present. When the causal relationship between the phenotype and the environment is misunderstood, it can lead to severe misinterpretation of the genetic parameters, including finding ‘phantom’ genetic variation for traits that, in reality, have none. We also demonstrate how using bivariate models can partly alleviate these issues. Finally, we provide the mathematical equations describing the expected estimated values. This study highlights that not taking gene–environment correlations into account can lead to erroneous interpretations of additive genetic variation and phenotypic plasticity estimates. If we aim to understand and predict how organisms adapt to environmental change, we need a better understanding of the mechanisms that may lead to gene–environment correlations.

Haplotype of each individual, together with population and location data

Behavioral Ecology, 2015

Preexisting receiver biases are well known and empirically supported alternatives or complements ... more Preexisting receiver biases are well known and empirically supported alternatives or complements to signal evolution through coevolving mate choice, but largely neglected as drivers of sexually or socially selected agonistic signal evolution. In further pursuit of a recently revealed receiver bias for red agonistic signaling in Euplectes (17 species of widowbirds and bishops), we investigate here its presence in the yellow-crowned bishop (Euplectes afer), a representative of the earliest phylogenetic branch of the genus. In a captive population in southern Spain, where the yellow-crowned bishop is invasive, we staged and filmed 10-min dyadic contests over access to a feeder, between males with experimentally yellow-(control-) and red-painted crown plumage, respectively. Red males secured significantly more time at the feeder, and tended to win more of the limited number of supplant attempts observed. This suggests that the previously demonstrated agonistic signal function of red carotenoid coloration in widowbirds also applies to the bishop birds, and may derive from a receiver bias (aversion) that is substantially older than the convergent gains of red plumage pigmentation in Euplectes, and perhaps also predating the evolution of red in a few other weaverbird (Ploceidae) lineages. Given the similarities in ecology and behavior across Euplectes, the color diversity appears to primarily be a consequence of evolutionary limitations on mechanisms for achieving red coloration.

Differential perception and subsequent differential use of habitats can generate local adaptation... more Differential perception and subsequent differential use of habitats can generate local adaptation, especially when natural selection cannot. However, this local adaptation is not maintained into future generations unless mating happens within the chosen habitats. We currently have no experimental data on whether differential perception of environments results in sexual isolation. We induced differential perception of environments by stimulating different olfactory neurons via light pulses (optogenetics) in two groups of fruit flies. These flies were released in a cage of which only one section received light pulses. One group of flies perceives this optogenetic stimulation as the smell of a harmful concentration of CO2 and was found to avoid the illuminated section. The other group perceives it as the smell of food-related compounds and was found to be attracted to the illuminated section. Due to this self-imposed spatial segregation, we subsequently observed a considerable degree o...

The model code in Netlogo format. Download (http://ccl.northwestern.edu/netlogo) and install NetL... more The model code in Netlogo format. Download (http://ccl.northwestern.edu/netlogo) and install NetLogo for free, and you can open and run the model directly