scholarly journals Visual habitat geometry predicts relative morph abundance in the colour-polymorphic ornate rainbowfish

2013 ◽  
Vol 280 (1752) ◽  
pp. 20122377 ◽  
Author(s):  
Daniel Hancox ◽  
Robbie S. Wilson ◽  
Craig R. White
Keyword(s):  
Sexual Selection ◽  
Signal Transmission ◽  
Aquatic Environments ◽  
Visual Context ◽  
Ambient Light ◽  
Polymorphic Species ◽  
Local Abundance ◽  
Selection For ◽  
Natural And Sexual Selection ◽  
Colour Signal

During colour signalling in aquatic environments, the colour of the ambient light, the background against which signals are viewed and signal transmission through the environment can all have profound impacts on the efficacy of a given signal. In colour-polymorphic species, where alternative morphs persist owing to a balance in the natural and sexual selection for each, changes to the visual context can have large effects on the local success and relative abundance of competing phenotypes. The ornate rainbowfish, Rhadinocentrus ornatus , is composed of populations that vary in the relative frequency of red and blue individuals, and inhabit sites that vary in water transmittance from clear (white) to heavily tannin-stained (red-shifted). Using spectroradiometry, we measured the downwelling and sidewelling irradiance, bank radiance and water transmittance of 10 R. ornatus habitats. We found that the relative local abundance of each morph was predicted not by water transmittance but by chromatic differences between the vertical (downwelling light) and horizontal (bank colour) components of the habitat. This visual habitat geometry should increase contrast between the colour signal and background, with large potential to influence the strength of natural and sexual selection in this system.

scholarly journals Natural and sexual selection act on different axes of variation in avian plumage color

2015 ◽  
Vol 1 (2) ◽  
pp. e1400155 ◽  
Author(s):  
Peter O. Dunn ◽  
Jessica K. Armenta ◽  
Linda A. Whittingham
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Habitat Type ◽  
Sexual Differences ◽  
Plumage Color ◽  
Evolutionary Transitions ◽  
Testes Size ◽  
Selection For ◽  
Bird Coloration ◽  
Natural And Sexual Selection

The bright colors of birds are often attributed to sexual selection on males, but in many species both sexes are colorful and it has been long debated whether sexual selection can also explain this variation. We show that most evolutionary transitions in color have been toward similar plumage in both sexes, and the color of both sexes (for example, bright or dull) was associated with indices of natural selection (for example, habitat type), whereas sexual differences in color were primarily associated with indices of sexual selection on males (for example, polygyny and large testes size). Debate about the evolution of bird coloration can be resolved by recognizing that both natural and sexual selection have been influential, but they have generally acted on two different axes: sexual selection on an axis of sexual differences and natural selection on both sexes for the type of color (for example, bright or dull).

scholarly journals The physical environment mediates male harm and its effect on selection in females

2017 ◽  
Vol 284 (1858) ◽  
pp. 20170424 ◽  
Author(s):  
Li Yun ◽  
Patrick J. Chen ◽  
Amardeep Singh ◽  
Aneil F. Agrawal ◽  
Howard D. Rundle
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Physical Environment ◽  
Selective Advantage ◽  
Laboratory Studies ◽  
Male Choice ◽  
Female Fitness ◽  
High Quality ◽  
Evolutionary Consequences ◽  
Natural And Sexual Selection

Recent experiments indicate that male preferential harassment of high-quality females reduces the variance in female fitness, thereby weakening natural selection through females and hampering adaptation and purging. We propose that this phenomenon, which results from a combination of male choice and male-induced harm, should be mediated by the physical environment in which intersexual interactions occur. Using Drosophila melanogaster , we examined intersexual interactions in small and simple (standard fly vials) versus slightly more realistic (small cages with spatial structure) environments. We show that in these more realistic environments, sexual interactions are less frequent, are no longer biased towards high-quality females, and that overall male harm is reduced. Next, we examine the selective advantage of high- over low-quality females while manipulating the opportunity for male choice. Male choice weakens the viability advantage of high-quality females in the simple environment, consistent with previous work, but strengthens selection on females in the more realistic environment. Laboratory studies in simple environments have strongly shaped our understanding of sexual conflict but may provide biased insight. Our results suggest that the physical environment plays a key role in the evolutionary consequences of sexual interactions and ultimately the alignment of natural and sexual selection.

scholarly journals Losses of female song with changes from tropical to temperate breeding in the New World blackbirds

2009 ◽  
Vol 276 (1664) ◽  
pp. 1971-1980 ◽  
Author(s):  
J. Jordan Price ◽  
Scott M. Lanyon ◽  
Kevin E. Omland
Keyword(s):  
Sexual Selection ◽  
New World ◽  
Female Song ◽  
Complex Song ◽  
Evolutionary Changes ◽  
Apparent Relationship ◽  
Song Production ◽  
Selection For ◽  
The Tropics

Birds in which both sexes produce complex songs are thought to be more common in the tropics than in temperate areas, where typically only males sing. Yet the role of phylogeny in this apparent relationship between female song and latitude has never been examined. Here, we reconstruct evolutionary changes in female song and breeding latitude in the New World blackbirds (Icteridae), a family with both temperate and tropical representatives. We provide strong evidence that members of this group have moved repeatedly from tropical to temperate breeding ranges and, furthermore, that these range shifts were associated with losses of female song more often than expected by chance. This historical perspective suggests that male-biased song production in many temperate species is the result not of sexual selection for complex song in males but of selection against such songs in females. Our results provide new insights into the differences we see today between tropical and temperate songbirds, and suggest that the role of sexual selection in the evolution of bird song might not be as simple as we think.

The New Synthesis

2018 ◽  
pp. 235-245
Author(s):  
Erika Lorraine Milam
Keyword(s):  
Sexual Selection ◽  
Information Processing ◽  
Human Nature ◽  
Genetic Information ◽  
Next Generation ◽  
New Synthesis ◽  
Genetic Information Processing ◽  
The 1960S ◽  
Natural And Sexual Selection

This chapter discusses new understandings of humanity from the 1960s onward. It shows how a particular group of scientists struggled with the question of human nature by conceiving of natural and sexual selection as acting at the level of individuals, who in turn served as genetic-information processing units. A trait could not spread in a population unless it conferred some advantage to the individuals who possessed it, allowing them to contribute more copies of their genes to the next generation of that population than other individuals. These struggles are furthermore framed within a period when sociobiology was just starting to get a foothold in academics.

Principles of evolutionary theory, evolutionary psychopathology, and genetics

2015 ◽  
pp. 3-40
Author(s):  
Martin Brüne
Keyword(s):  
Sexual Selection ◽  
Human Brain ◽  
Psychosomatic Medicine ◽  
Genetic Variants ◽  
Driving Force ◽  
Human Cognition ◽  
Protective Effects ◽  
Changing Environments ◽  
Genes And Environment ◽  
Natural And Sexual Selection

Darwin’s work on evolution by natural and sexual selection is the central scientific framework in biology that explains how life developed through adaptation to changing environments. Evolution has been the driving force that has shaped the human brain and mind in the same way as it has formed somatic traits. Many adaptations pertaining to human cognition, emotions, and behaviour emerged in ancestral environments of evolutionary adaptedness, from which modern living conditions deviate in one way or another. Such ‘mismatches’ of evolved traits and current environments may cause vulnerability to dysfunctional operation of cognitive, emotional, and behavioural traits. Genes and environment interact in manifold ways, yet genetic plasticity may not only convey vulnerability to dysfunction. Instead, the very same genetic variants that may lead to dysfunction when associated with environmental adversity exert protective effects against dysfunction when environments are more favourable. These insights have yet to be acknowledged by psychiatry and psychosomatic medicine.

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