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Ilik J. Saccheri - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Convergence of Industrial Melanism in Three Geometrid Moths
    Biology letters, 2019
    Co-Authors: Arjen E. Van’t Hof, Carl J. Yung, Louise A. Reynolds, Laurence M. Cook, Ilik J. Saccheri
    Abstract:

    The rise of dark (melanic) forms of many species of moth in heavily coal-polluted areas of nineteenth- and twentieth-century Britain, and their post-1970s fall, point to a common selective pressure (camouflage against bird predators) acting at the community level. The extent to which this convergent phenotypic response relied on similar genetic and developmental mechanisms is unknown. We examine this problem by testing the hypothesis that the locus controlling melanism in Phigalia pilosaria and Odontopera bidentata, two species of geometrid moth that showed strong associations between melanism and coal pollution, is the same as that controlling melanism in Biston betularia, previously identified as the gene cortex. Comparative linkage mapping using family material supports the hypothesis for both species, indicating a deeply conserved developmental mechanism for melanism involving cortex. However, in contrast to the strong selective sweep signature seen in British B. betularia, no significant association was detected between cortex-region markers and melanic morphs in wild-caught samples of P. pilosaria and O. bidentata, implying much older, or diverse, origins of melanic morph alleles in these latter species.

  • Colour change of twig-mimicking peppered moth larvae is a continuous reaction norm that increases camouflage against avian predators
    PeerJ, 2017
    Co-Authors: Amy Eacock, Nicola Edmonds, Hannah M. Rowland, Ilik J. Saccheri
    Abstract:

    Camouflage, and in particular background-matching, is one of the most common anti-predator strategies observed in nature. Animals can improve their match to the colour/pattern of their surroundings through background selection, and/or by plastic colour change. Colour change can occur rapidly (a few seconds), or it may be slow, taking hours to days. Many studies have explored the cues and mechanisms behind rapid colour change, but there is a considerable lack of information about slow colour change in the context of predation: the cues that initiate it, and the range of phenotypes that are produced. Here we show that peppered moth (Biston betularia) larvae respond to colour and luminance of the twigs they rest on, and exhibit a continuous reaction norm of phenotypes. When presented with a heterogeneous environment of mixed twig colours, individual larvae specialise crypsis towards one colour rather than developing an intermediate colour. Flexible colour change in this species has likely evolved in association with wind dispersal and polyphagy, which result in caterpillars settling and feeding in a diverse range of visual environments. This is the first example of visually induced slow colour change in Lepidoptera that has been objectively quantified and measured from the visual perspective of natural predators.

  • The industrial melanism mutation in British peppered moths is a transposable element
    Nature, 2016
    Co-Authors: Arjen E. Van’t Hof, Pascal Campagne, Daniel J. Rigden, Carl J. Yung, Jessica Lingley, Michael A. Quail, Neil Hall, Alistair C. Darby, Ilik J. Saccheri
    Abstract:

    Discovering the mutational events that fuel adaptation to environmental change remains an important challenge for evolutionary biology. The classroom example of a visible evolutionary response is industrial melanism in the peppered moth (Biston betularia): the replacement, during the Industrial Revolution, of the common pale typica form by a previously unknown black (carbonaria) form, driven by the interaction between bird predation and coal pollution. The carbonaria locus has been coarsely localized to a 200-kilobase region, but the specific identity and nature of the sequence difference controlling the carbonaria-typica polymorphism, and the gene it influences, are unknown. Here we show that the mutation event giving rise to industrial melanism in Britain was the insertion of a large, tandemly repeated, transposable element into the first intron of the gene cortex. Statistical inference based on the distribution of recombined carbonaria haplotypes indicates that this transposition event occurred around 1819, consistent with the historical record. We have begun to dissect the mode of action of the carbonaria transposable element by showing that it increases the abundance of a cortex transcript, the protein product of which plays an important role in cell-cycle regulation, during early wing disc development. Our findings fill a substantial knowledge gap in the iconic example of microevolutionary change, adding a further layer of insight into the mechanism of adaptation in response to natural selection. The discovery that the mutation itself is a transposable element will stimulate further debate about the importance of 'jumping genes' as a source of major phenotypic novelty.

  • The industrial melanism mutation in British peppered moths is a transposable element
    'Springer Science and Business Media LLC', 2016
    Co-Authors: Hof Aevt, Campagne P, Dj Rigden, Cj Yung, Lingley J, Hall N, Ac Darby, Ilik J. Saccheri
    Abstract:

    © 2016 Macmillan Publishers Limited. All rights reserved.Discovering the mutational events that fuel adaptation to environmental change remains an important challenge for evolutionary biology. The classroom example of a visible evolutionary response is industrial melanism in the peppered moth (Biston betularia): the replacement, during the Industrial Revolution, of the common pale typica form by a previously unknown black (carbonaria) form, driven by the interaction between bird predation and coal pollution. The carbonaria locus has been coarsely localized to a 200-kilobase region, but the specific identity and nature of the sequence difference controlling the carbonaria-typica polymorphism, and the gene it influences, are unknown. Here we show that the mutation event giving rise to industrial melanism in Britain was the insertion of a large, tandemly repeated, transposable element into the first intron of the gene cortex. Statistical inference based on the distribution of recombined carbonaria haplotypes indicates that this transposition event occurred around 1819, consistent with the historical record. We have begun to dissect the mode of action of the carbonaria transposable element by showing that it increases the abundance of a cortex transcript, the protein product of which plays an important role in cell-cycle regulation, during early wing disc development. Our findings fill a substantial knowledge gap in the iconic example of microevolutionary change, adding a further layer of insight into the mechanism of adaptation in response to natural selection. The discovery that the mutation itself is a transposable element will stimulate further debate about the importance of € jumping genes' as a source of major phenotypic novelty

  • selective bird predation on the peppered moth the last experiment of michael majerus
    Biology Letters, 2012
    Co-Authors: L M Cook, Bruce Grant, Ilik J. Saccheri
    Abstract:

    Colour variation in the peppered moth Biston betularia was long accepted to be under strong natural selection. Melanics were believed to be fitter than pale morphs because of lower predation at daytime resting sites on dark, sooty bark. Melanics became common during the industrial revolution, but since 1970 there has been a rapid reversal, assumed to have been caused by predators selecting against melanics resting on today's less sooty bark. Recently, these classical explanations of melanism were attacked, and there has been general scepticism about birds as selective agents. Experiments and observations were accordingly carried out by Michael Majerus to address perceived weaknesses of earlier work. Unfortunately, he did not live to publish the results, which are analysed and presented here by the authors. Majerus released 4864 moths in his six-year experiment, the largest ever attempted for any similar study. There was strong differential bird predation against melanic peppered moths. Daily selection against melanics (s ≃ 0.1) was sufficient in magnitude and direction to explain the recent rapid decline of melanism in post-industrial Britain. These data provide the most direct evidence yet to implicate camouflage and bird predation as the overriding explanation for the rise and fall of melanism in moths.

Graeme D Ruxton - One of the best experts on this subject based on the ideXlab platform.

  • mimicking multiple models polyphenetic masqueraders gain additional benefits from crypsis
    Behavioral Ecology, 2011
    Co-Authors: John Skelhorn, Graeme D Ruxton
    Abstract:

    Many prey organisms avoid predation by mimicking inanimate objects: a phenomenon known as masquerade. It is expected that masquerade will show a frequency-dependent advantage such that masquerading species benefit more from their appearance when they are rare in comparison with their models. In such circumstances, selection may favor the coexistence of different phenotypes (polyphenism or polymorphism). The American peppered moth caterpillar Biston betularia cognataria appears to show polyphenetic masquerade: caterpillars found on birch trees look like birch twigs; those on willow trees look like willow twigs. Here, we show in laboratory experiments that the caterpillar does benefit from masquerade and that polyphenism is key to this benefit: avian predators misclassified birch-fed larvae as birch twigs and willow-fed larvae as willow twigs. In a second experiment where the benefits of masquerade were excluded, we show that larvae are less likely to be attacked when located on the host species whose twigs they resemble than when found on an alternative species whose twigs they do not resemble; thus, the polyphenism provides antipredatory benefits through crypsis as well as through masquerade. This is the first time that a species has been demonstrated to have the capacity to benefit both from masquerade and from crypsis, and the first time, polyphenism has been demonstrated to benefit masquerade. Copyright 2011, Oxford University Press.

John Skelhorn - One of the best experts on this subject based on the ideXlab platform.

  • mimicking multiple models polyphenetic masqueraders gain additional benefits from crypsis
    Behavioral Ecology, 2011
    Co-Authors: John Skelhorn, Graeme D Ruxton
    Abstract:

    Many prey organisms avoid predation by mimicking inanimate objects: a phenomenon known as masquerade. It is expected that masquerade will show a frequency-dependent advantage such that masquerading species benefit more from their appearance when they are rare in comparison with their models. In such circumstances, selection may favor the coexistence of different phenotypes (polyphenism or polymorphism). The American peppered moth caterpillar Biston betularia cognataria appears to show polyphenetic masquerade: caterpillars found on birch trees look like birch twigs; those on willow trees look like willow twigs. Here, we show in laboratory experiments that the caterpillar does benefit from masquerade and that polyphenism is key to this benefit: avian predators misclassified birch-fed larvae as birch twigs and willow-fed larvae as willow twigs. In a second experiment where the benefits of masquerade were excluded, we show that larvae are less likely to be attacked when located on the host species whose twigs they resemble than when found on an alternative species whose twigs they do not resemble; thus, the polyphenism provides antipredatory benefits through crypsis as well as through masquerade. This is the first time that a species has been demonstrated to have the capacity to benefit both from masquerade and from crypsis, and the first time, polyphenism has been demonstrated to benefit masquerade. Copyright 2011, Oxford University Press.

Laurence M. Cook - One of the best experts on this subject based on the ideXlab platform.

  • Genetic Convergence of Industrial Melanism in Three Geometrid Moths
    Biology letters, 2019
    Co-Authors: Arjen E. Van’t Hof, Carl J. Yung, Louise A. Reynolds, Laurence M. Cook, Ilik J. Saccheri
    Abstract:

    The rise of dark (melanic) forms of many species of moth in heavily coal-polluted areas of nineteenth- and twentieth-century Britain, and their post-1970s fall, point to a common selective pressure (camouflage against bird predators) acting at the community level. The extent to which this convergent phenotypic response relied on similar genetic and developmental mechanisms is unknown. We examine this problem by testing the hypothesis that the locus controlling melanism in Phigalia pilosaria and Odontopera bidentata, two species of geometrid moth that showed strong associations between melanism and coal pollution, is the same as that controlling melanism in Biston betularia, previously identified as the gene cortex. Comparative linkage mapping using family material supports the hypothesis for both species, indicating a deeply conserved developmental mechanism for melanism involving cortex. However, in contrast to the strong selective sweep signature seen in British B. betularia, no significant association was detected between cortex-region markers and melanic morphs in wild-caught samples of P. pilosaria and O. bidentata, implying much older, or diverse, origins of melanic morph alleles in these latter species.

  • Melanic frequencies in three species of moths in post industrial Britain
    Biological Journal of the Linnean Society, 2002
    Co-Authors: Laurence M. Cook, A. M. Riley, Ian P. Woiwod
    Abstract:

    Changing patterns of morph frequency in three moth species (Biston betularia, Odontoptera bidentata and Apocheima pilosaria) have been investigated using data from the Rothamsted Insect Survey. All three exhibited industrial melanism during the period of high atmospheric pollution in Britain. Three historical and habitat types are compared, the old industrial north of England, rural Scotland, Wales and South-West England, and a southern English intermediate region of high human population density but generally low industrialization. Between 1974 and 1999 the carbonaria morph of B. betularia declined in frequency in the industrial region and is nearly absent from rural areas. It is the form which most closely tracks atmospheric change. It is shown that the insularia forms of B. betularia and the melanic morphs in the other two species have decreased in the industrial region, commencing later than carbonaria, but have maintained their presence and possibly reached equilibrium elsewhere. They may be non-industrial polymorphisms. B. betularia is rarer than the other species and all three species are at lower densities in industrial than in non-industrial regions.

  • Frequency of insularia during the decline in melanics in the peppered moth Biston betularia in Britain.
    Heredity, 2000
    Co-Authors: Laurence M. Cook, Bruce Grant
    Abstract:

    Over the last three decades the frequency of the dark melanic form carbonaria of the peppered moth Biston betularia has declined in Britain. Data have been examined which show the intermediate phenotype insularia, controlled by alleles at the same locus, to have increased or remained level in frequency. Phenotype frequency of insularia does not always track allele frequency accurately because it is recessive to its alternative when carbonaria is common but dominant to the alternative when typical is common. It is shown that if insularia fitness lies between that of carbonaria and typical, and melanics replace typicals or vice versa, there will be a rise and fall in insularia allele frequency during a transitory period. The path followed is strongly affected by initial gene frequencies. During the high melanic period in Britain, differences in insularia frequency between localities may have been influenced by history of arrival of the novel morphs as well as by local selective conditions.

  • Changing views on melanic moths
    Biological Journal of the Linnean Society, 2000
    Co-Authors: Laurence M. Cook
    Abstract:

    The rapid rise in frequency of melanic morphs in several moth species, especially the peppered moth Biston betularia, in industrial regions during the 19th century, and the subsequent rapid decline, indicate the action of strong selection. There has recently been a tendency to criticise and question all aspects of research on industrial melanism, including the experiments which suggest that selective predation plays an important part in the changes. These experiments are reexamined, together with evidence for changes in appearance of tree surfaces and for relation of initial melanic frequency to subsequent rate of decline. It is suggested that intense pollution may have been required to drive the carbonaria morph to a high frequency, with frequency patterns over a mosaic environment smoothed by migration. Improvements in these extreme locations then triggered the decline, with little indication of the environmental changes in areas of moderate pollution. Reasons for criticism of past work are discussed. Industrial melanism continues to provide an exceptional opportunity to analyse a pattern of selection and change in gene frequency.

Menegaz A. - One of the best experts on this subject based on the ideXlab platform.

  • “El juego de las mariposas”. Propuesta didáctica para el tratamiento del cambio biológico
    'Servicio de Publicaciones de la Universidad de Cadiz', 2017
    Co-Authors: Mengascini A., Menegaz A.
    Abstract:

    Se presenta una propuesta didáctica para el abordaje del concepto de cambio evolutivo que permite trabajar concepciones alternativas y llegar a una mejor comprensión del tema. La actividad consiste en una simulación de los cambios poblacionales de Biston betularia (melanismo industrial) y comprende la explicitación y análisis reflexivo de conocimientos previos, la formulación de hipótesis explicativas, y la revisión, resignificación y aplicación de los conceptos utilizados.Palabras clave:juego de simulación, cambio biológico, concepciones alternativas."The game of butterflies". Didactic proposal for the treatment of biological changeAn activity related to the concept of biological change is presented to attain a better comprehension of evolutionary processes and elicit alternative conceptions. The activity includes the simulation of changes en populations of Biston betularia together with an analysis about the elicited preconceptions, the formulation of hypothesis and a critical reflection and application of related concepts.Key words: simulation play, biological change, alternative conceptions