scholarly journals Evolutionary trade-offs between male secondary sexual traits revealed by a phylogeny of the hyperdiverse tribe Eumaeini (Lepidoptera: Lycaenidae)

2021 ◽  
Vol 288 (1950) ◽  
Author(s):  
Wendy A. Valencia-Montoya ◽  
Tiago B. Quental ◽  
João Filipe R. Tonini ◽  
Gerard Talavera ◽  
James D. Crall ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Secondary Sexual Traits ◽  
Secondary Sexual Characteristics ◽  
Sexually Selected Traits ◽  
Trade Offs ◽  
Sexual Characteristics ◽  
Phylogenetic Framework ◽  
Sexual Traits ◽  
Selected Traits ◽  
Secondary Sexual

Male butterflies in the hyperdiverse tribe Eumaeini possess an unusually complex and diverse repertoire of secondary sexual characteristics involved in pheromone production and dissemination. Maintaining multiple sexually selected traits is likely to be metabolically costly, potentially resulting in trade-offs in the evolution of male signals. However, a phylogenetic framework to test hypotheses regarding the evolution and maintenance of male sexual traits in Eumaeini has been lacking. Here, we infer a comprehensive, time-calibrated phylogeny from 379 loci for 187 species representing 91% of the 87 described genera. Eumaeini is a monophyletic group that originated in the late Oligocene and underwent rapid radiation in the Neotropics. We examined specimens of 818 of the 1096 described species (75%) and found that secondary sexual traits are present in males of 91% of the surveyed species. Scent pads and scent patches on the wings and brush organs associated with the genitalia were probably present in the common ancestor of Eumaeini and are widespread throughout the tribe. Brush organs and scent pads are negatively correlated across the phylogeny, exhibiting a trade-off in which lineages with brush organs are unlikely to regain scent pads and vice versa . In contrast, scent patches seem to facilitate the evolution of scent pads, although they are readily lost once scent pads have evolved. Our results illustrate the complex interplay between natural and sexual selection in the origin and maintenance of multiple male secondary sexual characteristics and highlight the potential role of sexual selection spurring diversification in this lineage.

scholarly journals Baseline corticosterone does not reflect iridescent plumage traits in female tree swallows

2018 ◽  
Author(s):  
Keneth Sarpong ◽  
Christine L. Madliger ◽  
Christopher M. Harris ◽  
Oliver P. Love ◽  
Stéphanie M. Doucet ◽  
...  
Keyword(s):  
Tree Swallows ◽  
Secondary Sexual Traits ◽  
Factors Affecting ◽  
Brood Rearing ◽  
Trade Offs ◽  
Female Tree ◽  
Baseline Corticosterone ◽  
Sexual Characteristics ◽  
The Relationship ◽  
Secondary Sexual

AbstractThe production of high quality secondary sexual traits can be constrained by trade-offs in the allocation of energy and nutrients with other metabolic activities, and is mediated by physiological processes. In birds, the factors influencing male plumage quality have been well studied; however, factors affecting female plumage quality are poorly understood. Furthermore, it remains uncertain which physiological traits mediate the relationship between body condition and ornaments. In this three-year study of after-second-year female tree swallows (Tachycineta bicolor), we investigated (1) the relationship between baseline corticosterone near the end of the brood-rearing period (CORTBR) and feather colour characteristics (hue, saturation, brightness) the following year, and (2) the relationship between baseline corticosterone measured during incubation (CORTI) and brood rearing (CORTBR), and feather colour in the same year. To control for reproductive effort, we included reproductive parameters as covariates in all analyses. In this first study between CORT and the plumage colour characteristics of a species bearing iridescent feathers, we did not find any relationship between CORTBRand the colour of subsequently-produced feathers, nor did we find any relationship between CORTIand the colour of feathers displayed during that breeding season. If CORT levels at the end of breeding carry over to influence the immediately subsequent moult period as we expect, our results generally indicate that structural plumage quality may not be as sensitive to circulating CORT levels compared to carotenoid-based colouration. Future studies, particularly those employing experimental manipulations of CORT during moult in species with iridescent traits, are necessary to fully determine the role glucocorticoids play in mediating the quality of secondary sexual characteristics.

scholarly journals Impact of trait exaggeration on sex-biased gene expression and genome architecture in a water strider

2020 ◽  
Author(s):  
William Toubiana ◽  
David Armisén ◽  
Corentin Dechaud ◽  
Roberto Arbore ◽  
Abderrahman Khila
Keyword(s):  
Gene Expression ◽  
Sexual Selection ◽  
Enrichment Analysis ◽  
Purifying Selection ◽  
Genome Architecture ◽  
Water Strider ◽  
Secondary Sexual Traits ◽  
Specific Trait ◽  
Sexual Traits ◽  
Secondary Sexual

AbstractExaggerated secondary sexual traits are widespread in nature and often evolve under strong directional sexual selection. Although heavily studied from both theoretical and empirical viewpoints, we have little understanding of how sexual selection influences sex-biased gene regulation during the development of sex-specific phenotypes, and how these changes are reflected in genomic architecture. This is primarily due to the lack of a representative genome and transcriptomes to study the development of secondary sexual traits. Here we present the genome and developmental transcriptomes, focused on the legs of the water strider Microvelia longipes, a species where males exhibit strikingly long third legs used as weapons. The quality of the genome assembly is such that over 90% of the sequence is captured in 13 scaffolds. The most exaggerated legs in males were particularly enriched in sex-biased genes, indicating a specific signature of gene expression in association with sex-specific trait exaggeration. We also found that male-biased genes showed patterns of fast evolution compared to non-biased and female-biased genes, indicative of directional or relaxed purifying selection. Interestingly, we found that female-biased genes that are expressed in the third legs only, but not male-biased genes, were over-represented in the X chromosome compared to the autosomes. An enrichment analysis for sex-biased genes along the chromosomes revealed that they can arrange in large genomic regions or in small clusters of two to four consecutive genes. The number and expression of these enriched regions were often associated with the exaggerated legs of males, suggesting a pattern of common regulation through genomic proximity in association with trait exaggeration. Our findings shed light on how directional sexual selection drives sex-biased gene expression and genome architecture along the path to trait exaggeration and sexual dimorphism.

3. Choosing from the field of competitors

2018 ◽  
pp. 34-51
Author(s):  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Mate Choice ◽  
Animal Species ◽  
Theoretical Models ◽  
Mating Preferences ◽  
Contemporary View ◽  
Sexual Characteristics ◽  
Sexual Traits ◽  
Secondary Sexual

There is now unequivocal evidence for Darwin’s long-rejected suggestion that females choose among potential mates based on their secondary sexual traits. This has shifted attention from the question of whether females exercised mate choice, to why they should exhibit the mating preferences they do. ‘Choosing from the field of competitors’ gives a contemporary view of mate choice and its occurrence in a wide variety of animal species, along with some examples of what females are choosing and why parasites and disease may play a role in the evolution of extravagant secondary sexual characteristics. Several theoretical models are discussed along with the role of sexual selection in the evolution of humans.

Sexual dimorphism and condition dependence in the anal pad of the small Indian mongoose (Herpestes auropunctatus)

2015 ◽  
Vol 93 (5) ◽  
pp. 397-402
Author(s):  
M.A. Owen ◽  
D.C. Lahti
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Indirect Evidence ◽  
Condition Dependence ◽  
Secondary Sexual Traits ◽  
Herpestes Auropunctatus ◽  
Sexual Traits ◽  
Indian Mongoose ◽  
Small Indian Mongoose ◽  
Secondary Sexual

Secondary sexual traits tend to be sexually dimorphic, and theory predicts that such traits should also be condition-dependent in a sex-specific manner. We investigate these phenomena in a field study of the small Indian mongoose (Herpestes auropunctatus (Hodgson, 1836); formerly Herpestes javanicus (É. Geoffroy Saint-Hillaire, 1818)), in the first attempt at understanding secondary sexual traits and sexual selection in this species. Small Indian mongooses are solitary and nonterritorial, and they likely depend on chemical (scent) rather than visual or acoustic signals for communication. Additionally, they possess a fleshy projection around their anus, the anal pad, thought to aid in scent-marking. Our results revealed strong male-biased sexual dimorphism in mass, skull and body lengths, canine diameters, and anal pad area. After controlling for the influence of body length, males were 31% heavier and possessed anal pads that were 68% larger than females’. Additionally, anal pad size was positively related to body size in males but not in females and was condition-dependent in males but not in females. Taken together, our findings provide indirect evidence that the anal pad might have evolved, at least in part, via sexual selection.

scholarly journals Sexual selection affects the evolution of physiological and life history traits

2021 ◽  
Author(s):  
Martin David Garlovsky ◽  
Luke Holman ◽  
Andrew L Brooks ◽  
Rhonda R Snook
Keyword(s):  
Sexual Selection ◽  
Life History ◽  
Sexual Conflict ◽  
Life History Traits ◽  
Experimental Manipulation ◽  
Endurance Capacity ◽  
Development Activity ◽  
Sexually Selected Traits ◽  
Trade Offs ◽  
Selected Traits

Sexual selection and sexual conflict are expected to affect all aspects of the phenotype, not only traits that are directly involved in reproduction. Here, we show coordinated evolution of multiple physiological and life history traits in response to long-term experimental manipulation of the mating system in populations of Drosophila pseudoobscura. Development time was extended under polyandry relative to monogamy in both sexes, potentially due to higher investment in traits linked to sexual selection and sexual conflict. Individuals (especially males) evolving under polyandry had higher metabolic rates and locomotor activity than those evolving under monogamy. Polyandry individuals also invested more in metabolites associated with increased endurance capacity and efficient energy metabolism and regulation, namely lipid and glycogen. Finally, polyandry males were less desiccation- and starvation-resistant than monogamy males, suggesting trade-offs between resistance and sexually selected traits. Our results provide experimental evidence that mating systems can impose selection that influences the evolution of non-sexual phenotypes such as development, activity, metabolism, and nutrient homeostasis.

scholarly journals Sexual selection: when to expect trade-offs

2010 ◽  
Vol 7 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Dave Shutler
Keyword(s):  
Sexual Selection ◽  
Empirical Evidence ◽  
Negative Binomial ◽  
Empirical Distributions ◽  
Sexually Selected Traits ◽  
Trade Offs ◽  
Selected Traits ◽  
Positive Correlations ◽  
The Way ◽  
Normally Distributed

Empirical evidence is mixed for interspecific trade-offs in investment among sexually selected traits. One important reason may be the way resources are allocated among species. Consider a set of species that obtains the same fitness pay-off for investment in song or plumage. Simulations where resources were normally distributed among species revealed significant trade-offs between song and plumage ( ± s.d. of r = −0.54 ± 0.06). However, simulations where resources were distributed in a negative binomial fashion usually produced positive correlations ( r = 0.11 ± 0.09). Repeating simulations on three published studies that concomitantly quantified elaboration of song and plumage indicated that trade-offs are likely, although these analyses make assumptions that require further evaluation. Moreover, there are currently too few empirical distributions to make generalizations about the likelihood of interspecific trade-offs in sexually selected traits.

Allometric relationships and character evolution in Onthophagus taurus (Coleoptera: Scarabaeidae)

2000 ◽  
Vol 78 (7) ◽  
pp. 1199-1206 ◽  
Author(s):  
Claudia Palestrini ◽  
Antonio Rolando ◽  
Paola Laiolo
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Small Body ◽  
Dung Beetle ◽  
Allometric Relationships ◽  
Secondary Sexual Traits ◽  
Onthophagus Taurus ◽  
Sexual Traits ◽  
External Body ◽  
Secondary Sexual

Allometric relationships in primary sexual traits (male and female genitalia), secondary sexual traits (male horns and female carinae), and non-sex-related traits (external body traits, epipharynx traits) were studied in the dung beetle Onthophagus taurus. Model II regressions of log-transformed data were used to quantify relationships, with pronotum width as regressor and indicator of overall body size. Slopes (allometric values) for the different trait categories were significantly different, with secondary sexual traits showing the highest values (higher than 1.0), followed by external body traits (slightly lower than 1.00) and epipharynx traits (around 0.2). Primary sexual traits and body size were mostly uncorrelated and genital sizes were virtually constant. Allometries of secondary sexual traits were quite different in the two sexes: the relationship between male horn length and pronotum width was approximately sigmoidal, while that between female carina length and pronotum width was linear. External body traits had significantly higher allometric values in females than in males. Our results suggest that traits in the different categories are under different kinds of selection. Genital allometries can be explained on the basis of sexual selection by cryptic female choice or by the lock-and-key hypothesis. Among secondary sexual characters, male horn morphology seems to be mostly "environmentally" determined and sexual selection would affect only a component of the developmental mechanism of horn expression. External body characters are likely under natural selection, even though a few traits could be sex-related. Finally, in both sexes, internal epipharynx traits seem to be subject to the same selective pressure, probably because males and females use the same feeding niche. The constancy of genital sizes in O. taurus suggests that in developmental processes, more is invested in primary sexual traits (to produce genitalia of the proper size) than in secondary sexual or body traits. Males receiving low quantities of food may incur costs associated with a small horn or small body size, but do not incur costs associated with small genitalia. Females probably share the same developmental pattern.

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