Sexual dimorphism and sex pheromone detection in Aphidoletes aphidimyza

2020 ◽  
Vol 70 (1) ◽  
pp. 13-25
Author(s):  
Aurore Nicolas ◽  
Julie Pourtois ◽  
Pol Karier ◽  
István Markó ◽  
Thierry Hance
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sex Pheromone ◽  
Choice Experiments ◽  
Morphometric Study ◽  
Sexually Dimorphic ◽  
Aphidoletes Aphidimyza ◽  
Long Distance ◽  
The Right ◽  
The Relationship

Abstract Sexual dimorphism, particularly at the level of sensory and locomotor organs, is usually attributed to sexual selection. Antennae are notably developed in males of species that need to detect a sex pheromone at low concentration or at long distance. In addition to their role in intrasexual selection, antennae can be seen as important ornaments in intersexual selection. Antennae of Aphidoletes aphidimyza are clearly sexually dimorphic (males have longer antennae than females, with highly developed sensilla) while females emit a sex pheromone for mating. Males with longer and more symmetrical antennae than others could be more successful in reaching the source of sex pheromone, especially if they can fly properly. A morphometric study was first conducted, to apprehend the variability of antennae, wings and tibias in lab conditions. The length of the antennae of male A. aphidimyza is impressive and the right antenna is longer than the left antenna. Secondly, choice experiments were conducted in a Y-shaped olfactometer with males of A. aphidimyza facing the sex pheromone. The relationship between choice patterns and morphology of males was then studied, but no link was found between the morphology of males and their behaviour while exposed to the sex pheromone, although males were indeed attracted by the olfactometer arm containing the sex pheromone.

scholarly journals Artificial sexual selection alters allometry in the stalk-eyed fly Cyrtodiopsis dalmanni (Diptera: Diopsidae)

1993 ◽  
Vol 62 (3) ◽  
pp. 213-222 ◽  
Author(s):  
Gerald S. Wilkinson
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Body Length ◽  
Sexually Dimorphic ◽  
Selected Lines ◽  
Variable Intensity ◽  
High Line ◽  
Cumulative Selection ◽  
Selection For ◽  
Selection Of

SummarySelection for increased and decreased ratio of eye span to body length was exerted on male stalk-eyed flies (Cyrtodiopsis dalmanni) from Malaysia using replicate selected and unselected lines. Response to selection was symmetrical. After 10 generations high line male eye span increased to 1·3 body lengths while low line male eye span declined to 1·1 body lengths. Realized heritabilities for eye span to body length ratio, estimated using regressions of deviations from unselected controls on cumulative selection differentials, were greater than zero for all four selected lines with average h2 = 0·35 + 0·06. The static linear allometric relationship between eye span and body length diverged between selected lines and rotated among selected line males in the same direction as among males in other sexually dimorphic diopsid species. Crosses between lines after 13 generations of selection indicate that the genes which influence relative eye span combine additively and do not exhibit sex linkage or maternal effects. The genetic correlation between the sexes, 0·29 + 0·05 as estimated by the regression of female on male change in eye span, did not prevent sexual dimorphism in eye span from diverging between lines. These results suggest that the exaggerated eye span of male C. dalmanni is maintained by natural selection opposing sexual selection rather than by lack of or asymmetry in additive genetic variation. Furthermore, the variation in sexual dimorphism for eye span-body length allometry observed among extant diopsid species is consistent with sexual selection of variable intensity acting on relative eye span.

scholarly journals Sexual dimorphism of viscerocranium-A logistic model

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Lucas del Vigna Peixoto ◽  
Stefany de Lima Gomes ◽  
Ana Amelia Barbieri ◽  
Francisco Carlos Groppo ◽  
Cristhiane Martins Schmidt ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Sexual Dimorphism ◽  
Regression Model ◽  
Logistic Model ◽  
Quantitative Method ◽  
Logistic Regression Model ◽  
Sexually Dimorphic ◽  
Qualitative And Quantitative ◽  
The Right

Introduction: Sex estimates are generally based on the evaluation of qualitative and quantitative aspects of anatomic structures, however, the latter has better reproducibility and reliability. Objective: Aiming to evaluate the viscerocranium as a tool for sexual prediction and verify the possibility of creation of a logistic regression model for sexual prediction. Materials and Methods: 167 craniums - 100 male and 67 female between 22 and 85 years old from a Brazilian university´s Biobank - were evaluated. Results: It was observed that of the measures carried out were presented as sexually dimorphic, except for the measures of the right frontozygomatic point – right zygion; left frontozygomatic point – left zygion. Besides, it was possible to create a logistic regression model Sex = [logits/Sex = -24.5 + (0.20 * Nasion - Naso spine) + (0.18 * Right zygion - Naso spine)]. Conclusion: It was concluded that the measures of the viscerocranium present themselves as a factor of sexual dimorphism and the quantitative method developed was 81.4% accurate.

Sexual dimorphism in two savannah sparrow populations

1980 ◽  
Vol 58 (3) ◽  
pp. 412-415 ◽  
Author(s):  
Patrick J. Weatherhead
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Stabilizing Selection ◽  
Sexually Dimorphic ◽  
Mainland Population ◽  
Savannah Sparrow ◽  
Savannah Sparrows ◽  
Insular Population

Contrary to predictions, a monogamous, mainland population of savannah sparrows was found to be more sexually dimorphic than a polygynous, insular population. When only trophic characters were considered, the insular population fit the prediction of greater sexual dimorphism. Several explanations for increased sexual selection or decreased stabilizing selection in the more dimorphic population are considered. While none of the explanations seem readily applicable from the available evidence, further avenues of investigation are suggested.

scholarly journals How and why patterns of sexual dimorphism in human faces vary across the world

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Karel Kleisner ◽  
Petr Tureček ◽  
S. Craig Roberts ◽  
Jan Havlíček ◽  
Jaroslava Varella Valentova ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Mate Choice ◽  
Body Height ◽  
Human Populations ◽  
Sexually Dimorphic ◽  
Shape Variation ◽  
Cross Cultural Differences ◽  
Facial Shape ◽  
Human Faces

AbstractSexual selection, including mate choice and intrasexual competition, is responsible for the evolution of some of the most elaborated and sexually dimorphic traits in animals. Although there is sexual dimorphism in the shape of human faces, it is not clear whether this is similarly due to mate choice, or whether mate choice affects only part of the facial shape difference between men and women. Here we explore these questions by investigating patterns of both facial shape and facial preference across a diverse set of human populations. We find evidence that human populations vary substantially and unexpectedly in both the magnitude and direction of facial sexually dimorphic traits. In particular, European and South American populations display larger levels of facial sexual dimorphism than African populations. Neither cross-cultural differences in facial shape variation, sex differences in body height, nor differing preferences for facial femininity and masculinity across countries, explain the observed patterns of facial dimorphism. Altogether, the association between sexual shape dimorphism and attractiveness is moderate for women and weak (or absent) for men. Analysis that distinguishes between allometric and non-allometric components reveals that non-allometric facial dimorphism is preferred in women’s faces but not in faces of men. This might be due to different regimes of ongoing sexual selection acting on men, such as stronger intersexual selection for body height and more intense intrasexual physical competition, compared with women.

Differences in sexual dimorphism among four gazelle taxa (Gazella spp.) in the Middle East

2010 ◽  
Vol 60 (4) ◽  
pp. 395-412 ◽  
Author(s):  
Peter Cunningham ◽  
Martin Plath ◽  
Torsten Wronski ◽  
Mohamed Sandouka
Keyword(s):  
Body Weight ◽  
Sexual Selection ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Mating Systems ◽  
Research Centre ◽  
Sexually Dimorphic ◽  
Male Sex ◽  
The Difference ◽  
Horn Development

AbstractSexual selection can lead to sexual dimorphism, where elaborated traits used in mate attraction or weaponry are more expressed in the male sex. The degree of sexual dimorphism, however, is known to vary even among closely related taxa. Here we examined sexual dimorphism in horn length and three measures related to body size (body weight, shoulder height, and neck circumference) in four gazelle taxa, representing at least three species, i.e. Dorcas gazelle (G. dorcas), Sand gazelle (G. subgutturosa marica) and Mountain gazelle (G. gazella). The latter is represented by two distinctive phenotypes maintained and bred at the King Khalid Wildlife Research Centre in Saudi Arabia. We describe marked differences in sexual dimorphism among taxa. For example, the difference in sexually dimorphic horn development was driven primarily by females exhibiting pronounced differences in horn development. We discuss how divergent mating systems, and group sizes affect these differences among the examined taxa, with more competition in larger groups probably promoting the evolution of larger horns in females, thereby leading to less sexual dimorphism.

scholarly journals Is male dimorphism under sexual selection in humans? A meta-analysis

2020 ◽  
Author(s):  
L. H. Lidborg ◽  
C. P. Cross ◽  
L. G. Boothroyd
Keyword(s):  
Sexual Selection ◽  
Meta Analysis ◽  
Sexually Dimorphic ◽  
Pitch Height ◽  
Voice Pitch ◽  
Male Dimorphism ◽  
Men And Women ◽  
Digit Ratios ◽  
Craniofacial Structure ◽  
The Relationship

AbstractHumans are sexually dimorphic: men and women differ in body build and composition, craniofacial structure, and voice pitch, likely mediated in part by developmental testosterone. Sexual selection hypotheses posit that, ancestrally, more ‘masculine’ men may have acquired more mates and/or sired more viable offspring. Thus far, however, evidence for either association is unclear. Here, we meta-analyze the relationship between six masculine traits and mating/reproductive outcomes (96 studies, 474 effects, N = 177,044). Voice pitch, height, digit ratios, and testosterone all predicted mating; however, strength/muscularity was the strongest and only consistent predictor of both mating and reproduction. Facial masculinity did not significantly predict either. There was insufficient evidence for any effects of masculinity on offspring viability. Our findings support arguments that strength/muscularity can be considered sexually selected in humans, but raise concerns over other forms of masculinity and highlight the need to increase tests of evolutionary hypotheses outside of industrialized populations.

Sex Recognition in Zebra Finch Males Results From Early Experience

Behaviour ◽  
1994 ◽  
Vol 128 (1-2) ◽  
pp. 1-14 ◽  
Author(s):  
Dave R. Vos
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Zebra Finch ◽  
White Male ◽  
Morphological Characteristics ◽  
Early Experience ◽  
White Female ◽  
Sexually Dimorphic ◽  
Sex Recognition ◽  
Sexual Imprinting

AbstractThis study investigated whether sexual imprinting plays a role in the recognition of the sex of conspecifics. Subjects were zebra finch males that had been raised with either normal pairs, white pairs or pairs of both morphs. They were tested for their preferences in six two-stimuli tests covering all combinations of both morphs of either sex. Males of all groups showed a clear preference for females of their mother's morph over males of their father's morph. Moreover, a majority of the males from mixed parentage preferred a male of their mother's morph over a female of their father's morph, indicating that morphological characteristics are more important than behavioural differences for discrimination between the sexes. This was confirmed in a subsequent series of tests in which males raised by parents of the white morph, which are sexually dimorphic only in respect to the intensity of the red colour of the bill, were given a choice between a white male with his bill painted orange and a white female with her bill painted red. All males of this group preferred to court the male in this test. In addition to differential responses in a sexual context, males showed discrimination in an aggressive context; that is, most aggression was directed towards stimulus birds resembling the father. The implications of these results for the evolution of sexual dimorphism and sexual selection are considered.

scholarly journals How and why patterns of sexual dimorphism in human faces vary across the world

2020 ◽  
Author(s):  
Karel Kleisner ◽  
Petr Tureček ◽  
S. Craig Roberts ◽  
Jan Havlicek ◽  
Jaroslava Varella Valentova ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Mate Choice ◽  
Body Height ◽  
Human Populations ◽  
Sexually Dimorphic ◽  
Shape Variation ◽  
Cross Cultural Differences ◽  
Facial Shape ◽  
Human Faces

Sexual selection, including mate choice and intrasexual competition, is responsible for the evolution of some of the most elaborated and sexually dimorphic traits in animals. Although there is clear sexual dimorphism in the shape of human faces, it is not clear whether this is similarly due to mate choice, or whether mate choice affects only part of the facial shape difference between men and women. Here we explore these questions by investigating patterns of both facial shape and facial preference across a diverse set of human populations. We find evidence that human populations vary substantially and unexpectedly in both the range and pattern of facial sexually dimorphic traits. In particular, European and South American populations display larger levels of facial sexual dimorphism than African populations. Neither cross-cultural differences in facial shape variation, differences in body height between sexes, nor differing preferences for facial sex-typicality across countries, explain the observed patterns of facial dimorphism. Altogether, the association between morphological sex-typicality and attractiveness is moderate for women and weak (or absent) for men. Analysis that distinguishes between allometric and non-allometric components reveals that non-allometric sex-typicality is preferred in women’s faces but not in faces of men. This might be due to different regimes of ongoing sexual selection acting on men, such as stronger intersexual selection for body height and more intense intrasexual physical competition, compared with women.

scholarly journals Sex differences in ocular morphology in Caucasian people: a dubious role of sexual selection in the evolution of sexual dimorphism of the human eye

2020 ◽  
Vol 74 (10) ◽  
Author(s):  
Dariusz P. Danel ◽  
Sławomir Wacewicz ◽  
Karel Kleisner ◽  
Zdzisław Lewandowski ◽  
Mariska E. Kret ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Facial Attractiveness ◽  
Total Surface Area ◽  
Sexually Dimorphic ◽  
Human Eye ◽  
Eye Morphology ◽  
Caucasian Men

Abstract The horizontal size of the exposed depigmented sclera in Caucasians has been previously suggested to be sexually dimorphic, and the significance of this phenomenon remains unclear. Here we build on a previous study and extend it by (i) examining sex differences in other measures of ocular morphology and (ii) exploring the link between eye morphology and biometric markers of facial attractiveness. We used facial photographs of 100 Caucasians (50 men) from Eastern-Central Europe and digitally measured four ocular features. Eye measurements were tested for sex differences and associations with morphometric data on facial averageness and sexual shape dimorphism. We found that sclera surface is more horizontally exposed in men, even though the total surface area is similar in both sexes. We also found that eye fissures are rounder (less rectangular) in women than in men and that irises are brighter in women. We did not find any relationship between the examined eye features and two aspects of facial attractiveness: facial averageness and sexual dimorphism in facial shape. Despite being sexually dimorphic, eye features may be loosely linked with the development of facial sexual ornamentation. The role of sexual selection in the evolution of the observed phenomena is disputable. Significance statement It is often argued that because of their physical appearance, human eyes are crucial to interpersonal and social interactions. In many aspects, however, the significance of the human eye architecture is unclear. In this study, we examine sex differences in eye morphology and explore the link between ocular features and biometric measures of facial attractiveness in Caucasian men and women. We found that despite being sexually dimorphic, eye features may be loosely linked with biometric markers of facial attractiveness. We argue that the role of sexual selection in the evolution of the observed sex differences is disputable.

scholarly journals Independent evolution of the sexes promotes amphibian diversification

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142213 ◽  
Author(s):  
Stephen P. De Lisle ◽  
Locke Rowe
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sexual Size Dimorphism ◽  
Alternative Hypothesis ◽  
Ecological Theory ◽  
Adaptive Landscape ◽  
Extinction Rate ◽  
Independent Evolution ◽  
Threat Status ◽  
The Relationship

Classic ecological theory predicts that the evolution of sexual dimorphism constrains diversification by limiting morphospace available for speciation. Alternatively, sexual selection may lead to the evolution of reproductive isolation and increased diversification. We test contrasting predictions of these hypotheses by examining the relationship between sexual dimorphism and diversification in amphibians. Our analysis shows that the evolution of sexual size dimorphism (SSD) is associated with increased diversification and speciation, contrary to the ecological theory. Further, this result is unlikely to be explained by traditional sexual selection models because variation in amphibian SSD is unlikely to be driven entirely by sexual selection. We suggest that relaxing a central assumption of classic ecological models—that the sexes share a common adaptive landscape—leads to the alternative hypothesis that independent evolution of the sexes may promote diversification. Once the constraints of sexual conflict are relaxed, the sexes can explore morphospace that would otherwise be inaccessible. Consistent with this novel hypothesis, the evolution of SSD in amphibians is associated with reduced current extinction threat status, and an historical reduction in extinction rate. Our work reconciles conflicting predictions from ecological and evolutionary theory and illustrates that the ability of the sexes to evolve independently is associated with a spectacular vertebrate radiation.

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