scholarly journals Role of sexual imprinting in assortative mating and premating isolation in Darwin’s finches

2018 ◽  
Vol 115 (46) ◽  
pp. E10879-E10887 ◽  
Author(s):  
Peter R. Grant ◽  
B. Rosemary Grant
Keyword(s):  
Natural Habitat ◽  
Good Choice ◽  
Premating Isolation ◽  
Sexual Imprinting ◽  
Darwin's Finches ◽  
Darwin’S Finches ◽  
Adaptive Radiations ◽  
Beak Size ◽  
Species Specific

Global biodiversity is being degraded at an unprecedented rate, so it is important to preserve the potential for future speciation. Providing for the future requires understanding speciation as a contemporary ecological process. Phylogenetically young adaptive radiations are a good choice for detailed study because diversification is ongoing. A key question is how incipient species become reproductively isolated from each other. Barriers to gene exchange have been investigated experimentally in the laboratory and in the field, but little information exists from the quantitative study of mating patterns in nature. Although the degree to which genetic variation underlying mate-preference learning is unknown, we provide evidence that two species of Darwin’s finches imprint on morphological cues of their parents and mate assortatively. Statistical evidence of presumed imprinting is stronger for sons than for daughters and is stronger for imprinting on fathers than on mothers. In combination, morphology and species-specific song learned from the father constitute a barrier to interbreeding. The barrier becomes stronger the more the species diverge morphologically and ecologically. It occasionally breaks down, and the species hybridize. Hybridization is most likely to happen when species are similar to each other in adaptive morphological traits, e.g., body size and beak size and shape. Hybridization can lead to the formation of a new species reproductively isolated from the parental species as a result of sexual imprinting. Conservation of sufficiently diverse natural habitat is needed to sustain a large sample of extant biota and preserve the potential for future speciation.

scholarly journals Darwin's finches - an adaptive radiation constructed from ancestral genetic modules

2021 ◽  
Author(s):  
Carl-Johan Rubin ◽  
Erik D Enbody ◽  
Mariya P Dobreva ◽  
Arkhat Abzhanov ◽  
Brian W Davis ◽  
...  
Keyword(s):  
Environmental Variability ◽  
Phenotypic Diversity ◽  
Introgressive Hybridization ◽  
Ancestral Haplotype ◽  
Darwin's Finches ◽  
Haplotype Blocks ◽  
Darwin’S Finches ◽  
Adaptive Radiations ◽  
Beak Size ◽  
Genomic Regions

Recent adaptive radiations are models for investigating mechanisms contributing to the evolution of biodiversity. An unresolved question is the relative importance of new mutations, ancestral variants, and introgressive hybridization for phenotypic evolution and speciation. Here we address this issue using Darwin's finches, which vary in size from an 8g warbler finch with a pointed beak to a 40g large ground finch with a massive blunt beak. We present a highly contiguous genome assembly for one of the species and investigate the genomic architecture underlying phenotypic diversity in the entire radiation. Admixture mapping for beak and body size in the small, medium and large ground finches revealed 28 loci showing strong genetic differentiation. These loci represent ancestral haplotype blocks with origins as old as the Darwin's finch phylogeny (1-2 million years). Genes expressed in the developing beak are overrepresented in these genomic regions. Frequencies of allelic variants at the 28 loci covary with phenotypic similarities in body and beak size across the Darwin's finch phylogeny. These ancestral haplotypes constitute genetic modules for selection, and act as key determinants of the exceptional phenotypic diversity of Darwin's finches. Such ancestral haplotype blocks can be critical for how species adapt to environmental variability and change.

Inseparable Impulses: The Science and Aesthetics of Ernst Haeckel and Charley Harper

Leonardo ◽  
2013 ◽  
Vol 46 (5) ◽  
pp. 465-470 ◽  
Author(s):  
Megan K. Halpern ◽  
Hannah Star Rogers
Keyword(s):  
Scientific Theory ◽  
Visual Language ◽  
Ernst Haeckel ◽  
Darwin's Finches ◽  
Darwin’S Finches ◽  
Art Forms ◽  
Specific Interpretation ◽  
Scientific Argument

This article examines the role of aesthetics in scientific argument by analyzing two images. The first, from Ernst Haeckel's Art Forms in Nature (1904), depicts 15 bats evenly spaced on a white field. The second, Charley Harper's Darwin's Finches (1961), shows 13 finches, similarly displayed. Although these two images may at first appear to have little in common, they both present a specific interpretation of Darwin's theories using visual language. This article argues that the act of representation and scientific theory are inextricably intertwined.

scholarly journals Mechanical stress, fracture risk and beak evolution in Darwin's ground finches ( Geospiza )

2010 ◽  
Vol 365 (1543) ◽  
pp. 1093-1098 ◽  
Author(s):  
Joris Soons ◽  
Anthony Herrel ◽  
Annelies Genbrugge ◽  
Peter Aerts ◽  
Jeffrey Podos ◽  
...  
Keyword(s):  
Common Ancestor ◽  
High Stress ◽  
Natural Populations ◽  
Peak Stress ◽  
Food Type ◽  
Darwin's Finches ◽  
Darwin’S Finches ◽  
Competition For Food ◽  
Selection For ◽  
Beak Size

Darwin's finches have radiated from a common ancestor into 14 descendent species, each specializing on distinct food resources and evolving divergent beak forms. Beak morphology in the ground finches ( Geospiza ) has been shown to evolve via natural selection in response to variation in food type, food availability and interspecific competition for food. From a mechanical perspective, however, beak size and shape are only indirectly related to birds' abilities to crack seeds, and beak form is hypothesized to evolve mainly under selection for fracture avoidance. Here, we test the fracture-avoidance hypothesis using finite-element modelling. We find that across species, mechanical loading is similar and approaches reported values of bone strength, thus suggesting pervasive selection on fracture avoidance. Additionally, deep and wide beaks are better suited for dissipating stress than are more elongate beaks when scaled to common sizes and loadings. Our results illustrate that deep and wide beaks in ground finches enable reduction of areas with high stress and peak stress magnitudes, allowing birds to crack hard seeds while limiting the risk of beak failure. These results may explain strong selection on beak depth and width in natural populations of Darwin's finches.

scholarly journals Cranial shape evolution in adaptive radiations of birds: comparative morphometrics of Darwin's finches and Hawaiian honeycreepers

2017 ◽  
Vol 372 (1713) ◽  
pp. 20150481 ◽  
Author(s):  
Masayoshi Tokita ◽  
Wataru Yano ◽  
Helen F. James ◽  
Arhat Abzhanov
Keyword(s):  
Adaptive Radiation ◽  
Molecular Mechanisms ◽  
Rapid Evolution ◽  
Oceanic Islands ◽  
Shape Variation ◽  
Skull Morphology ◽  
Darwin's Finches ◽  
Hawaiian Honeycreepers ◽  
Darwin’S Finches ◽  
Adaptive Radiations

Adaptive radiation is the rapid evolution of morphologically and ecologically diverse species from a single ancestor. The two classic examples of adaptive radiation are Darwin's finches and the Hawaiian honeycreepers, which evolved remarkable levels of adaptive cranial morphological variation. To gain new insights into the nature of their diversification, we performed comparative three-dimensional geometric morphometric analyses based on X-ray microcomputed tomography (µCT) scanning of dried cranial skeletons. We show that cranial shapes in both Hawaiian honeycreepers and Coerebinae (Darwin's finches and their close relatives) are much more diverse than in their respective outgroups, but Hawaiian honeycreepers as a group display the highest diversity and disparity of all other bird groups studied. We also report a significant contribution of allometry to skull shape variation, and distinct patterns of evolutionary change in skull morphology in the two lineages of songbirds that underwent adaptive radiation on oceanic islands. These findings help to better understand the nature of adaptive radiations in general and provide a foundation for future investigations on the developmental and molecular mechanisms underlying diversification of these morphologically distinguished groups of birds. This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.

scholarly journals Sexual selection and natural selection in bird speciation

1998 ◽  
Vol 353 (1366) ◽  
pp. 251-260 ◽  
Author(s):  
Trevor Price
Keyword(s):  
Sexual Selection ◽  
Adaptive Radiation ◽  
Species Recognition ◽  
Correlated Response ◽  
Premating Isolation ◽  
Sexual Imprinting ◽  
Sexually Selected Traits ◽  
Isolating Mechanisms ◽  
Selected Traits

The role of sexual selection in speciation is investigated, addressing two main issues. First, how do sexually selected traits become species recognition traits? Theory and empirical evidence suggest that female preferences often do not evolve as a correlated response to evolution of male traits. This implies that, contrary to runaway (Fisherian) models of sexual selection, premating isolation will not arise as an automatic side effect of divergence between populations in sexually selected traits. I evaluate premating isolating mechanisms in one group, the birds. In this group premating isolation is often a consequence of sexual imprinting, whereby young birds learn features of their parents and use these features in mate choice. Song, morphology and plumage are known recognition cues. I conclude that perhaps the main role for sexual selection in speciation is in generating differences between populations in traits. Sexual imprinting then leads to these traits being used as species recognition mechanisms. The second issue addressed in this paper is the role of sexual selection in adaptive radiation, again concentrating on birds. Ecological differences between species include large differences in size, which may in themselves be sufficient for species recognition, and differences in habitat, which seem to evolve frequently and at all stages of an adaptive radiation. Differences in habitat often cause song and plumage patterns to evolve as a result of sexual selection for efficient communication. Therefore sexual selection is likely to have an important role in generating premating isolating mechanisms throughout an adaptive radiation. It is also possible that sexual selection, by creating more allopatric species, creates more opportunity for ecological divergence to occur. The limited available evidence does not support this idea. A role for sexual selection in accelerating ecological diversification has yet to be demonstrated.

scholarly journals The consequences of craniofacial integration for the adaptive radiations of Darwin’s finches and Hawaiian honeycreepers

2020 ◽  
Vol 4 (2) ◽  
pp. 270-278 ◽  
Author(s):  
Guillermo Navalón ◽  
Jesús Marugán-Lobón ◽  
Jen A. Bright ◽  
Christopher R. Cooney ◽  
Emily J. Rayfield
Keyword(s):  
Darwin's Finches ◽  
Hawaiian Honeycreepers ◽  
Darwin’S Finches ◽  
Adaptive Radiations

scholarly journals Adult sex ratio influences mate choice in Darwin’s finches

2019 ◽  
Vol 116 (25) ◽  
pp. 12373-12382 ◽  
Author(s):  
Peter R. Grant ◽  
B. Rosemary Grant
Keyword(s):  
Mate Choice ◽  
Sex Ratio ◽  
Phylogenetic Analyses ◽  
Sex Ratios ◽  
Differential Mortality ◽  
Sexual Imprinting ◽  
Darwin's Finches ◽  
Darwin’S Finches ◽  
Adult Sex Ratio ◽  
Geospiza Fortis

The adult sex ratio (ASR) is an important property of populations. Comparative phylogenetic analyses have shown that unequal sex ratios are associated with the frequency of changing mates, extrapair mating (EPM), mating system and parental care, sex-specific survival, and population dynamics. Comparative demographic analyses are needed to validate the inferences, and to identify the causes and consequences of sex ratio inequalities in changing environments. We tested expected consequences of biased sex ratios in two species of Darwin’s finches in the Galápagos, where annual variation in rainfall, food supply, and survival is pronounced. Environmental perturbations cause sex ratios to become strongly male-biased, and when this happens, females have increased opportunities to choose high-quality males. The choice of a mate is influenced by early experience of parental morphology (sexual imprinting), and since morphological traits are highly heritable, mate choice is expressed as a positive correlation between mates. The expected assortative mating was demonstrated when theGeospiza scandenspopulation was strongly male-biased, and not present in the contemporaryGeospiza fortispopulation with an equal sex ratio. Initial effects of parental imprinting were subsequently overridden by other factors when females changed mates, some repeatedly. Females of both species were more frequently polyandrous in male-biased populations, and fledged more offspring by changing mates. The ASR ratio indirectly affected the frequency of EPM (and hybridization), but this did not lead to social mate choice. The study provides a strong demonstration of how mating patterns change when environmental fluctuations lead to altered sex ratios through differential mortality.

scholarly journals Reproductive isolation of sympatric morphs in a population of Darwin's finches

2007 ◽  
Vol 274 (1619) ◽  
pp. 1709-1714 ◽  
Author(s):  
Sarah K Huber ◽  
Luis Fernando De León ◽  
Andrew P Hendry ◽  
Eldredge Bermingham ◽  
Jeffrey Podos
Keyword(s):  
Strong Support ◽  
Darwin's Finches ◽  
Early Stages ◽  
Darwin’S Finches ◽  
Ecological Resources ◽  
Geospiza Fortis ◽  
Breeding Seasons ◽  
Assortative Pairing ◽  
Sympatric Morphs

Recent research on speciation has identified a central role for ecological divergence, which can initiate speciation when (i) subsets of a species or population evolve to specialize on different ecological resources and (ii) the resulting phenotypic modes become reproductively isolated. Empirical evidence for these two processes working in conjunction, particularly during the early stages of divergence, has been limited. We recently described a population of the medium ground finch, Geospiza fortis , that features large and small beak morphs with relatively few intermediates. As in other Darwin's finches of the Galápagos Islands, these morphs presumably diverged in response to variation in local food availability and inter- or intraspecific competition. We here demonstrate that the two morphs show strong positive assortative pairing, a pattern that holds over three breeding seasons and during both dry and wet conditions. We also document restrictions on gene flow between the morphs, as revealed by genetic variation at 10 microsatellite loci. Our results provide strong support for the central role of ecology during the early stages of adaptive radiation.

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