Male-male competition, ornamentation and the role of testosterone in sexual selection in red jungle fowl

1990 ◽  
Vol 40 (2) ◽  
pp. 367-373 ◽  
Author(s):  
J. David Ligon ◽  
Randy Thornhill ◽  
Marlene Zuk ◽  
Kristine Johnson
Keyword(s):  
Sexual Selection ◽  
Male Competition ◽  
Red Jungle Fowl

Effects of Natural Variation in Sex Ratio and Habitat Structure On Mate-Guarding Decisions in Amphipods (Crustacea)

Behaviour ◽  
1996 ◽  
Vol 133 (13-14) ◽  
pp. 985-996 ◽  
Author(s):  
Jaimie T.A. Dick ◽  
Robert W. Elwood
Keyword(s):  
Natural Populations ◽  
Mate Guarding ◽  
Reproductive Behaviour ◽  
Male Competition ◽  
Female Body Size ◽  
The Social ◽  
Size Assortment ◽  
Assortative Pairing ◽  
Study Species

AbstractWe employed field-based studies, with complementary laboratory-based studies, to investigate social and environmental influences on tactical mate-guarding decisions in amphipods (Crustacea). Firstly, we investigated variation in precopulatory mate-guarding duration in Cammarus duebeni celticus in relation to the social structure of natural populations. Variation in population density of up to two orders of magnitude had no effect on precopula duration, whereas guarding durations increased as the sex ratios of the populations became more male biased. That is, males have some ability to assess the probability of other males taking females into precopula and are prepared to guard for longer as this threat of male: male competition increases. A field demonstration of tactical shifts in reproductive behaviour in response to pertinent social conditions is thus provided. Secondly, the 'habitat segregation' hypothesis, which proposes that positive size-assortative pairing in amphipod populations arises due to variation in the use of micro-habitats, was tested in natural field populations and under laboratory conditions in Echinogammarus marinus. This was necessary in order to distinguish any purely environmental determinants of size-assortment from the role of active decisions by males concerning mate choice and male: male competition. The hypothesis was rejected on the grounds that size-assortative pairing arises under both heterogeneous and homogeneous environmental conditions. Further, in both study species, male and female body size were positively correlated with precopula duration. Thus, indirect competition for access to large, fecund females, based on the timing of male entry into precopula, together with direct aggression, provides the explanation for size-assortative pairing in amphipods.

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.

Adaptation

2012 ◽  
Author(s):  
Lee Cronk ◽  
Beth L. Leech
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Levels Of Explanation ◽  
Different Levels ◽  
Culture And Language ◽  
Evolutionary Explanations

This chapter examines the concept of adaptation and how it is applied (and sometimes misapplied) to cooperation. It starts with George C. Williams's idea that adaptation is a “special and onerous concept that should be used only where it is really necessary,” which he articulated in Adaptation and Natural Selection. It then considers different levels of explanation that help clarify the notion of adaptation, fortuitous benefits and by-product mutualism in relation to adaptation, and the link between adaptation and natural, artificial, social, and sexual selection. It also explores how phylogeny constrains natural selection, the ways that adaptations solve specific problems found in specific environments, and how adaptation influences judgment. Finally, it analyzes the role of culture and language in adaptation and evolutionary explanations of morality.

Using Meta-analysis to Test Ecological and Evolutionary Theory

2013 ◽  
Author(s):  
Michael D. Jennions ◽  
Christopher J. Lortie ◽  
Julia Koricheva
Keyword(s):  
Sexual Selection ◽  
Sex Ratio ◽  
Case Studies ◽  
Evolutionary Theory ◽  
Meta Analysis ◽  
Basic Research ◽  
Fighting Behavior ◽  
Main Research ◽  
Sex Ratio Theory

This chapter describes nine case studies that illustrate how meta-analysis has contributed to theoretical developments in basic research in ecology and evolution. The main research topics cover are maintenance of biodiversity (Case 1); sexual selection (mate choice/fighting behavior) (cases 2, 8, 9); sex ratio theory (Case 3); allometric scaling (Case 4); the invasiveness of exotic plants (Case 5); seed size and plant abundance (Case 6); and the role of competition and predation in structuring communities (Case 7). It is hoped that these case studies will resonate with the reader and provide “templates” for ways to conduct comparable tests on analogous controversies in their own fields of research.

Male terminalia morphology of sixteen species of the Drosophila saltans group Sturtevant (Diptera, Drosophilidae)

Zootaxa ◽  
2021 ◽  
Vol 5061 (3) ◽  
pp. 523-544
Author(s):  
BRUNA EMILIA ROMAN ◽  
LILIAN MADI-RAVAZZI
Keyword(s):  
Sexual Selection ◽  
Sibling Species ◽  
Potential Role ◽  
Rapid Evolution ◽  
Variable Structure ◽  
Diagnostic Feature ◽  
Internal Fertilization ◽  
Saltans Group

Male terminalia in insects with internal fertilization evolve more rapidly than other structures. The aedeagus is the most variable structure, making it a valuable diagnostic feature to distinguish species. The saltans group Sturtevant of Drosophila Fallén contains sibling species, that can be distinguished by their aedeagi. Here, we revised and illustrated the morphology of the male terminalia of the following species: Drosophila prosaltans Duda, 1927; D. saltans Sturtevant, 1916; D. lusaltans Magalhães, 1962; D. austrosaltans Spassky, 1957; D. septentriosaltans Magalhães, 1962; D. nigrosaltans Magalhães, 1962; D. pseudosaltans Magalhães, 1956; D. sturtevanti Duda, 1927; D. lehrmanae Madi-Ravazzi et al., 2021; D. dacunhai Mourão & Bicudo, 1967; D. milleri Magalhães, 1962; D. parasaltans Magalhães, 1956; D. emarginata Sturtevant, 1942; D. neoelliptica Pavan & Magalhães in Pavan, 1950; D. neosaltans Pavan & Magalhães in Pavan, 1950 and D. neocordata Magalhães, 1956. We found that phallic structures (e.g., the aedeagus) evolve more rapidly than periphallic structures (e.g., epandrium), being completely different among the subgroups and within them. This rapid evolution may be due to the action of sexual selection or to the potential role of those structures in speciation.  

The Origins and Dynamics of Inequality

2021 ◽  
Author(s):  
Jon D. Wisman
Keyword(s):  
Sexual Selection ◽  
Evolutionary Psychology ◽  
The Political ◽  
Human History ◽  
Central Importance ◽  
Social Scientists ◽  
Political Dynamics ◽  
The Past ◽  
Historical Role

Whereas President Barack Obama identified inequality as “the defining challenge of our time,” this book claims more: it is the defining issue of all human history. The struggle over inequality has been the underlying force driving human history’s unfolding. Drawing on the dynamics of inequality, this book reinterprets history and society. Beyond according inequality the central role in human history, this book is novel in two other respects. First, transcending the general failure of social scientists and historians to anchor their work in explicit theories of human behavior, this book grounds the origins and dynamics of inequality in evolutionary psychology, or, more specifically, Darwin’s theory of sexual selection. Second, this book is novel in according central importance to the critical historical role of ideology in legitimating inequality, a role typically ignored or given little attention by social scientists and historians. Because of the central role of inequality in history, inequality’s explosion over the past 45 years has not been an anomaly. It is a return to the political dynamics by which elites have, since the rise of the state, taken practically everything for themselves, leaving all others with little more than the means with which to survive. Due to elites’ persuasive ideology, even after workers in advanced capitalist countries gained the franchise to become the overwhelming majority of voters, inequality continued to increase. The anomaly is that the only intentional politically driven decline in inequality occurred between the 1930s and 1970s following the Great Depression’s partial delegitimation (this should remain delegitimation globally) of elites’ ideology.

Diversity and Relationships

2020 ◽  
pp. 114-150
Author(s):  
Mona Sue Weissmark
Keyword(s):  
Sexual Selection ◽  
Social Relations ◽  
Human Mind ◽  
Social Psychological ◽  
Men And Women ◽  
The Social ◽  
Clinical Consequences ◽  
Key Issues ◽  
And Gender

This chapter outlines key issues in scientific literature concerning how evolutionary processes have shaped the human mind. To that end, psychologists have drawn on Charles Darwin’s sexual selection hypothesis, or how males compete for reproduction and the role of female choice in the process. Darwin argued that evolution hinged on the diversity resulting from sexual reproduction. Evolutionary psychologists posit that heterosexual men and women evolved powerful, highly patterned, and universal desires for particular characteristics in a mate. Critics, however, contend that Darwin’s theory of sexual selection was erroneous, in part because his ideas about sexual identity and gender were influenced by the social mores of his elite Victorian upper class. Despite this critique, some researchers argue similarly to Darwin that love is part of human biological makeup. According to their hypotheses, cooperation is the centerpiece of human daily life and social relations. This makes the emotion of love, both romantic and maternal love, a requirement not just for cooperation, but also for the preservation and perpetuation of the species. That said, researchers speculate that encounters with unfamiliar people, coincident with activated neural mechanisms associated with negative judgments, likely inspire avoidance behavior and contribute to emotional barriers. This suggests the need to further study the social, psychological, and clinical consequences of the link between positive and negative emotions.

Cryptic Diversity and Sexual Selection

2020 ◽  
pp. 447-471
Author(s):  
Matthias Galipaud ◽  
Loïc Bollache ◽  
Clément Lagrue
Keyword(s):  
Sexual Selection ◽  
Morphological Traits ◽  
Character Displacement ◽  
Secondary Contact ◽  
Cryptic Diversity ◽  
Reproductive Character Displacement ◽  
Behavioral Traits ◽  
Genetic Techniques ◽  
Existing Data

Recent advances in molecular and genetic techniques have revealed tremendous hidden genetic diversity in plants and animals. Crustaceans are no exception and, in fact, present one of the highest levels of cryptic diversity among the metazoans. Beyond the importance of such discovery and its multiple implications for taxonomy and ecology, it is now timely to investigate the potential causes of cryptic diversity. This chapter reviews the theoretical and experimental literature, seeking evidences for a relationship between sexual selection and cryptic diversity in crustaceans. It proposes three scenarios for the role of sexual selection on the origin and maintenance of pre-mating isolation and genetic divergence among crustacean populations, and suggests ways to discriminate among them experimentally or using existing data. Assuming that taxonomic identification is largely based on differences in sexually selected morphological traits, it also reviews evidence for a cryptic action of sexual selection on crustacean phenotypes. Specifically, if sexual selection acts primarily on chemical, visual, or behavioral traits, it is likely that allopatric crustacean populations remain morphologically similar even when they are reproductively isolated. This review shows that the strength of sexual selection likely differs among allopatric populations but does not seem to consistently induce pre-mating isolation (e.g. as in copepods and amphipods). Research is now needed to try to identify general patterns and determine the role of sexual selection on pre-mating isolation after secondary contact between populations, through reinforcement and reproductive character displacement.

scholarly journals Plumage iridescence is associated with distinct feather microbiota in a tropical passerine

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Veronika Gvoždíková Javůrková ◽  
Erik D. Enbody ◽  
Jakub Kreisinger ◽  
Kryštof Chmel ◽  
Jakub Mrázek ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Community Structure ◽  
Microbial Communities ◽  
Plumage Coloration ◽  
Microbial Load ◽  
Sexual Dichromatism ◽  
Physiological Processes ◽  
Fitness Consequences ◽  
Future Work

Abstract Birds present a stunning diversity of plumage colors that have long fascinated evolutionary ecologists. Although plumage coloration is often linked to sexual selection, it may impact a number of physiological processes, including microbial resistance. At present, the degree to which differences between pigment-based vs. structural plumage coloration may affect the feather microbiota remains unanswered. Using quantitative PCR and DGGE profiling, we investigated feather microbial load, diversity and community structure among two allopatric subspecies of White-shouldered Fairywren, Malurus alboscapulatus that vary in expression of melanin-based vs. structural plumage coloration. We found that microbial load tended to be lower and feather microbial diversity was significantly higher in the plumage of black iridescent males, compared to black matte females and brown individuals. Moreover, black iridescent males had distinct feather microbial communities compared to black matte females and brown individuals. We suggest that distinctive nanostructure properties of iridescent male feathers or different investment in preening influence feather microbiota community composition and load. This study is the first to point to structural plumage coloration as a factor that may significantly regulate feather microbiota. Future work might explore fitness consequences and the role of microorganisms in the evolution of avian sexual dichromatism, with particular reference to iridescence.

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