Sexual Shape Research Articles

Sexual dimorphism in the size and shape of the raptorial pedipalps of Giant Whip Spiders (Arachnida: Amblypygi)

AbstractSexual dimorphism in the form of elaborate crests, horns and swellings can be a clear indicator of the differing evolutionary pressures to which males and females are subject. However, dimorphism can also be expressed in more subtle shape differences not outwardly obvious to the observer. Whip spiders (Amblypygi) possess a unique pair of spined pedipalps hypothesized to primarily function in prey capture, but also serving multiple other functions. Little is known regarding the intraspecific shape variation of these limbs and its potential causes. Because a role during courtship and male contest has also been hypothesized, sexual selection may contribute to shape differences. As such, we hypothesize that sexual dimorphism will be present in the size and shape of amblypygid pedipalps, with male contest selecting for longer and thicker pedipalps, and larger spines in males. This study aims to test this hypothesis, by quantifying the contribution of ontogeny and sexual dimorphism to shape within the raptorial pedipalps of Damon variegatus. Discriminant function analysis using GMM landmark data reveals statistically significant sexual shape dimorphism in both the tibia and femur of the pedipalp. Contrary to our hypothesis, males display a more gracile pedipalp morphology with reduced spination. Sex differences in the allometric slope and overall size were also found in a number of linear appendicular metrics using Type‐II regression. Males have statistically longer pedipalp tibiae, whip femora, and leg two femora. We propose that males have evolved a longer pedipalps in the context of display contest rather than physical aggression. The elongation of structures used in display‐based contest and courtship found herein further emphasizes the contribution of visual cues to the evolution of morphology more broadly.

Black Lesbian Feminist Intellectuals and the Struggle against HIV/AIDS

This essay examines the significance of the work of three black lesbian feminist intellectuals--Cathy Cohen, Evelynn Hammonds, Linda Villarosa--to intellectual genealogies of HIV/AIDS. Since the early era of the AIDS epidemic, these scholars have challenged dominant and indigenous discourses of HIV/AIDS through traditional and public forms of scholarship. Working across an array of disciplines, they have helped us to understand the disproportionate effects of AIDS on black communities not as a matter of “risk” and inherent “deviance,” but as an effect of multiple marginalization. Moreover, these black lesbian feminist intellectuals have challenged some of the prevailing epistemological assumptions about the epidemic: examining how racial, class, gender, and sexual biases shape state and community responses to the epidemic, and the erasure and othering of black women in state and media discourses. Foregrounding the significance of black lesbian feminist identity and politics to their knowledge production, the essay demonstrates how the work of black lesbian feminist intellectuals extends the long history of black health activism into the late 20th and 21st centuries, while stressing the importance of lesbian sexuality to historical examinations of black (women's) intellectual traditions.

Characterization of the unarmored dinoflagellate Pseliodinium pirum (Ceratoperidiniaceae) from Jiaozhou Bay, China

SUMMARYA strain of Pseliodinium pirum was isolated from Jiaozhou Bay, China, identified based on a recently emended classification, and further characterized for its morphology using light, scanning electron, and transmission electron microscopy, and phylogeny based on SSU and partial LSU rDNA sequences. The pigment composition, life history, and potential effects on aquatic animals were also examined. We observed the typical characteristics of Ceratoperidiniaceae, in which its apical structure complex (ASC) formed a circular loop, and the ASC of our isolate comprised four to five rows of vesicles, and connected with sulcal intrusion. Epifluorescence and transmission electron microscopy revealed a bean‐shaped, centrally located nucleus, with at least 76 chromosomes. Numerous rod‐shaped chloroplasts were in connection to the irregularly shaped pyrenoids. Pigment analysis showed that peridinin was the most abundant among all carotenoids and other pigments. Phylogenetic analyses using maximum likelihood and Bayesian inference indicated that our isolate is conspecific with the entity Cochlodinium cf. helix (accession No. KF245459), but different from Ceratoperidinium, Kirithra, and other unidentified species of the family Ceratoperidiniaceae. Pseliodinium pirum could produce sexual, thin‐walled cyst, with subspherical and spherical shape and smooth surface (without spines or rough projections). The cyst could germinate within 3 days. Bioassays did not show adverse effects of P. pirum on the finfish Oryzias melastigma and the rotifer Brachionus plicatilis, indicating it may not be a harmful species.

Foregrounding intersectionality in rural youth’s schooling experiences in China: a queer re-reading

This article uses a queer lens in an intersectional analysis of students’ schooling experiences in rural China. I argue that a queer perspective has been largely neglected and issues related to sexuality have not been carefully investigated in Chinese educational contexts. Drawing on queer theory and an intersectional framework, I re-interpret one of my earlier qualitative studies ‘queerly’ and examine the different ways that the discourses of sexuality and gender shape rural Chinese students’ schooling lives. Findings reveal that these discourses marginalize both effeminate boys who demonstrate ‘too little’ masculinity and male ‘troublemakers’ who perform ‘too much’ masculinity. This queer route of rereading also disrupts other constructions of normalcy associated with class- and place-based identities, such as students’ ‘half-rural identity.’ The analysis shows the importance of foregrounding the intersectional dimensions of inequalities and embracing a queer theoretical framework in understanding rural education in China.

How sexual and natural selection shape sexual size dimorphism: Evidence from multiple evolutionary scales

Abstract Sexual size dimorphism (SSD) is pervasive across taxa and reflects differences in the effects of sexual and natural selection on body size between the sexes. However, disentangling the complex eco‐evolutionary interactions between these two mechanisms remains a major challenge for biologists. Here, we combine macro‐evolutionary (between‐species), local evolutionary (between‐population) and fine‐scale evolutionary (within‐population) patterns of SSD to explore how sexual and natural selection interact and shape the evolution of SSD in Australian agamid lizards. Australian agamid lizards show substantial variation in SSD, ecological traits and species density making them an ideal study system to address this question. At the between‐species level, population density, ecological generalism and mean species size significantly predict SSD variation; however, only ecological generalism was found to significantly explain variation in larger‐than‐average male‐biased SSD. At the population level, density positively correlated with SSD in native habitats, but not city park habitats. Last, agonistic behaviour acted as the primary driver of SSD at the within‐population level. Our results indicate how sexual and natural selection can interact at different evolutionary scales, and show the importance of considering both selective mechanisms when investigating patterns of SSD. A plain language summary is available for this article.

Interspecific size- and sex-related variation in the cranium of European brown frogs (Genus Rana)

The vertebrate skull is considered as phylogenetically conserved, but shows extensive diversification in many clades due to various environmental, climate and habitat influences. We explored the cranial size and shape differences of three closely related brown frog species, Rana temporaria, R. dalmatina and R. graeca to emphases the interspecific variation and intraspecific sexual differences, the allometric patterns in cranial shape changes and the relationship between cranial shape, phylogeny, and ecological similarity. Brown frogs significantly differ in cranial size and shape. Interspecific cranial shape changes are under strong influence of size variation. When size is considered, our results show that R. dalmatina is the most divergent species, while differences between R. dalmatina and R. temporaria cranial shapes are diminished when size is removed and peculiar features of R. graeca cranium arise (the most robust and rounded cranium). In both cases, with size and without size, major shape changes are related to the position of quadratum and width of the cranium at the level of anterior margin of eye. When comparing non-allometric shape with ecological similarity and phylogenetic relatedness we found that ecologically similar but phylogenetically more distant species shared the cranial morphology. Intraspecific patterns of cranial phenotypic variation in brown frogs showed significant cranium sexual size and shape dimorphism and absence of allometric scaling between sexes. More detailed studies on the relation of morphology and ecology in brown frogs are necessary to explain the mechanism behind cranial size and shape variation.

Lost in the (National) Archive: The Modern Girl and the Magazine

This essay forms part of a special online issue of modernism/modernity focusing on methods of reading the magazine, using the case study of Canada's Western Home Monthly. It focuses on the way in which national, aesthetic, and sexual politics shape and exclude certain figures and stories from literary history, on the one hand; and on the opportunities afforded by studying magazines for revising traditional understandings of national literary history, and literary modernity, on the other. Once sidelined as merely commercial artefacts, magazines were long considered enemies of women and literary culture, both of which they promiscuously courted and entangled. More recent scholarship of magazines—beginning with important work of Margaret Beetham on Victorian periodials, and extending into the Modernist Journals Project, which inspired the Canadian equivalent Modern Magazines Project (out of which this essay cluster arises)—have highlighted their value in assisting scholars to understand what was widely read in its own time and place, in ways that force serious reconsiderations of the literary past. As Anne Ardis has observed, these reconsiderations have have important implications for understandings of literary modernism, more wedded as it typically is to the logics of cultural scarcity, and for broader understandings of literary modernity, including literary feminism. This essay is self-reflexive methods-based reading of one full year of this monthly periodical, October 1931-October 1932, which raises issues about how its stories featuring the Modern Girl (more typically known as the Flapper), challenge established understandings of literary, cultural, and feminist history of Canada.

Sexual orientation at work: Documenting and understanding wage inequality

AbstractA growing body of research focuses on the labor market experiences and outcomes of LGBTQ+ people. Yet sexual orientation has been incorporated unevenly into research on labor market inequality, developing in parallel across work in labor economics and the sociology of work and organizations. In this review, we describe research on sexual orientation and wage inequality, bridging insights from quantitative studies of wage gaps and qualitative work on the organizational and occupational experiences of sexual minorities. We further discuss theoretical developments in the sociology of sexuality to provide background to the concepts and measures both bodies of research employ in practice. We argue that future research should integrate these approaches to consider how local and diffuse cultural understandings of sexual orientation shape the valuation of workers.

Sexual dimorphism in the Chinese endemic species Pachyhynobius shangchengensis Fei, Qu and Wu, 1983 (Urodela: Hynobiidae).

Sexual dimorphism (SD) is a widespread phenomenon in most vertebrate species and is exhibited in a myriad of ways. In amphibians, sexual size dimorphism, in which females are larger than males, is the most common type, and sexual shape dimorphism varies among species. Different selection forces (sexual selection, fecundity selection, and ecological selection) that act differently upon the sexes form the consequence of SD. Thus, studies of SD provide information about the general intersexual divergence of the same species and allow insights into the impact of selective forces on the sexes. In this study, we analyzed morphometric data of the Shangcheng stout salamander, Pachyhynobius shangchengensis, an endemic and poorly known Chinese salamander, to examine sexual dimorphism in size and shape. The morphometric data included 15 characteristics of 68 females and 55 males which were analyzed using univariate and multivariate methods. A significant difference was found between the sexes in terms of both body size (snout-vent length) and some body shapes (e.g., head length and width, tail length and width, distance between limbs, and limb length and width) in this salamander. The longer snout-vent length in males may be attributed to sexual selection, longer and wider head in males may contribute to male-male competition, longer and wider tail in males may be attributed to energy storage and reproductive success, the larger distance between limbs in females is likely due to a fecundity advantage, and longer and more robust limbs in males may be related to reproductive or competitive behaviors. These results demonstrated that sexual dimorphism of different morphological traits is the consequence of different selection forces that act differently upon the sexes.

Mechanical incompatibility caused by modifications of multiple male genital structures using genomic introgression inDrosophila*

Mechanical incompatibility of male and female genitalia is common in animals with internal fertilization. However, our knowledge regarding the precise mechanisms is limited. One key question regards the susceptibility of the match between male and female genitalia to morphological modification. To address this issue, we generated six different second-chromosome introgression lines possessing partially Drosophila mauritiana-like genital morphology in multiple structures in D. simulans background. Three of the six introgression males showed elevated mobility at some stages during copulation with D. simulans females; this was assumed to be an indication of genital mismatch. Notably, one of the introgression males with D. mauritiana-like enlarged anal plates showed occasional leakage of adhesive ejaculate on the body surface when mated with pure D. simulans females, suggesting apparent structural incompatibility in genital coupling. These observations suggested that both sexual and natural selection shape the anal plate morphology, highlighting the role of this structure as an important component of mechanical isolation. Partial replacement (introgression) by a sibling species genome can induce perturbations in genital coupling mechanics, suggesting that genital compatibility can be susceptible to subtle genomic changes at the early stages of divergence in these species.

Migration and Adolescent Health

Migration and Adolescent Health

Early sex shape dimorphism (SShD) in Rachycentron canadum (Linnaeus, 1766) and its applications for monosex culture

Rachycentron canadum (cobia) is a species that has attracted the interest of the marine fish farming industry due to displaying numerous traits favorable to cultivation. The species is characterized by its large size, rapid growth, robustness and established technological support for cultivation. Cobia shows sexual size dimorphism (SSD) as adults, with females being significantly larger than males. In fish, sexual dimorphism related to morphology can be the result of ecological, functional, or adaptive selection. Methodologies that allow the application of monosex cultures increase both the biotechnological and production potential of a species. With a view to establishing parameters for early sex determination in R. canadum, morphological analyses were conducted in juveniles aged 139 days (4.6 months) using geometric morphometrics. Sexual shape dimorphism (SShD) in female cobia is expressed by an elongated body and extended space between pectoral and anal fins, suggesting fecundity-related morphological adaptations. The results are promising and indicate a high index of early sex discrimination using geometric morphometrics, demonstrating the possibility of developing routine protocols that can be applied to increase species production.

Heroism and Comics Form: Feminist and Queer Speculations

Heroism and Comics Form: Feminist and Queer Speculations

In pursuit of intimacy: disability stigma, womanhood and intimate partnerships in South Africa

Notions of womanhood inculcate naturalised ideologies of femininity, sexuality, motherhood and caregiving. The paper asks how disability stigma intersects with womanhood to characterise intimate partnerships in South Africa. In-depth interviews with 30 women with a range of disabilities were conducted in informal settlements in Cape Town. Findings suggest that disability stigma may hamper attainment of normative womanhood and sexual relationships for women with disabilities in South Africa. Limited opportunities to meet potential partners, hegemonic gender expectations and restricted sexual and physical contact shape their intimate partnerships. However, women with disabilities also challenge ableist constructs of normalcy and discredit negative images of disabled womanhood. Because of this, theoretical models of intimate partner violence should consider the influence of disability on constructions of sexuality and norms in intimate partnerships. Building on women with disabilities’ stigma-avoidance strategies will help facilitate better relationship outcomes. Social norms interventions with broader society, communities, women with disabilities and their partners, family and carers can help destabilise assumptions that women with disabilities are unable to have long-lasting and fulfilling sexual and intimate partnerships. Moreover, accessible and relevant sexuality education and information on relationships, intimate partner violence, maternal and sexual and reproductive health care can ensure healthy and safe intimate partnerships for women with disabilities.

Wing morphometrics of Aedes (Ochlerotatus) albifasciatus (Macquart, 1838) (Diptera: Culicidae) from different climatic regions of Argentina

BackgroundGene flow restrictions between populations of Aedes albifasciatus, the vector of Western equine encephalitis and Dirophilaria immitis, have been described in the central region of Argentina. Genetic and eco-physiological variations usually result in local forms reflecting the climatic regions. Mosquito wings and their different parts have ecological functions in flight and communication. Therefore, wing shape could be considered an aspect of sexual dimorphism, and its eco-physiological responses can be expressed as morphological changes induced by the environment.MethodsTo compare the geographical and sexual variations with respect to wing shape and size in two Ae. albifasciatus populations from contrasting climates of Argentina (temperate: Buenos Aires, and the arid steppe of Patagonia: Sarmiento), the wings of adults reared in thermal trays at different constant temperatures (10–29 °C) were analyzed.ResultsThe wing size of Ae. albifasciatus showed inverse linear relationships with the rearing thermal condition and higher slope for Buenos Aires. In the cool range (10–17 °C), geographical size variations responded to the converse Bergmann’s rule, where Buenos Aires individuals were larger than those from Sarmiento. Sexual shape dimorphism occurred in both populations while geographical variation in shape was observed in both sexes.ConclusionsBuenos Aires individuals showed greater response sensitivity with respect to the size-temperature relation than those from Sarmiento. The converse Bergmann’s rule in size variation could be due to a higher development rate in Sarmiento to produce more cohorts in the limited favorable season. The shape could be more relevant with respect to the size in the study of population structures due to the size being more liable to vary due to changes in the environment. The geographical variations with respect to morphology could be favored by the isolation between populations and adaptations to the environmental conditions. Our results demonstrate that the shape and size of wing provide useful phenotypic information for studies related to sexual and environmental adaptations.

Ontogenetic shape changes and sexual dimorphism in Aegla marginata Bond-Buckup and Buckup, 1994.

A study on relative growth, sexual dimorphism and ontogenetic trajectory was carried out in a population of the aeglidAegla marginata coming from Barrinha River, Iguape River Basin, Tunas do Paraná, Paraná State, Brazil. The size the of morphological sexual maturity was estimated for males and females. The analysis of sexual dimorphism and ontogenetic trajectory were performed using geometric morphometric technique. Males reach maturity with 10.58 mm of carapace length (CL) and females with 10.38 mm CL. Sexual size dimorphism was only visible among adults, with males reaching larger sizes. This is probably related to the reproductive strategy of males. However, sexual shape dimorphism was found for both juveniles and adults: the posterior region of the carapace was wider in females. As the contrast of this feature was stronger in adults, it can be considered that large abdomen is advantageous for egg incubation. The allometric trajectories of juveniles presented similar directions, becoming divergent during the adult phase. The shape variation inA. marginataoccurred gradually throughout its development, with no abrupt transformation upon reaching sexual maturity. The reproductive adaptation is the main reason for the morphological variation within populations ofA. marginata.

Delineating modern variation from extinct morphology in the fossil record using shells of the Eastern Box Turtle (Terrapene carolina).

Characterization of morphological variation in the shells of extant Eastern Box Turtles, Terrapene carolina, provides a baseline for comparison to fossil populations. It also provides an example of the difficulties inherent to recognizing intraspecific diversity in the fossil record. The degree to which variation in fossils of T. carolina can be accommodated by extant variation in the species has been disagreed upon for over eighty years. Using morphometric analyses of the carapace, I address the relationship between modern and fossil T. carolina in terms of sexual dimorphism, geographic and subspecific variation, and allometric variation. Modern T. carolina display weak male-biased sexual size dimorphism. Sexual shape dimorphism cannot be reliably detected in the fossil record. Rather than a four-part subspecific division, patterns of geographic variation are more consistent with clinal variation between various regions in the species distribution. Allometric patterns are qualitatively similar to those documented in other emydid turtles and explain a significant amount of shape variation. When allometric patterns are accounted for, Holocene specimens are not significantly different from modern specimens. In contrast, several geologically older specimens have significantly different carapace shape with no modern analogue. Those large, fossilized specimens represent extinct variation occupying novel portions of morphospace. This study highlights the need for additional documentation of modern osteological variation that can be used to test hypotheses of intraspecific evolution in the fossil record.

Quantifying the shape variation of the elytra in Patagonian populations of the ground beetle Ceroglossus chilensis (Coleoptera: Carabidae)

Elytra shape variation was analyzed from two forest systems in the Chilean Patagonia, one composed of Nothofagus dombeyi and N. nitida and a second-growth stand of N. pumilo. Geometric morphometrics analysis and multivariate analyses were used on the complete elytra having the shape information (outline) of the trait. The results show several shape variations on the mid bottom of the elytra and confirm the local adaptation of the Patagoninan population at different traits with the results found at the abdominal section of previous studies of the same species, nevertheless, here we found a complete absence of sexual shape dimorphism using the elytra as a trait of sexual differentiation. A positive allometry was found, however, this was not related with sexual dimorphism differentiation but rather with to the forest and second-growth forest.

Real Men Get the Best Bar Girls: Performing Masculinities in China’s Global Sex Industry

ABSTRACTThe shifting power relations in China after the global financial crisis are redefining masculinity for both Western and Asian men. Connell (1995) argues that in most societies a hegemonic masculinity usually exists that privileges heterosexual middle-class and economically successful men who exhibit characteristics associated with being masculine. The global financial crisis has led to a new global financial order that has created paths for people to reimagine hierarchies of class, gender, nation, race, and sexuality. “Entangled masculinities” recognizes that the intersections of class, gender, nation, race, and sexuality shape identities of male clients who buy commercial sex. The article looks specifically at clients from three niche commercial sex markets (low, mid, and high tier) in Dongguan, China. Specifically, five patterns of behavior exhibited by male clients to rationalize and assert their masculinity will be analyzed in depth: vigorous and macho; austere and essentialist; suppressive and anxious; extravagant and competitive; and refined and collaborative. This article argues clients with vigorous and macho, austere and essentialist, and suppressive and anxious behavior types are frequently found in low-end and mid-tier bars. Patrons of higher-tier bars tended to engage in extravagant and competitive and refined and collaborative behavior through expressions of wealth and power.

Lesbian, Gay, and Bisexual Contact with Police in Chicago: Disparities across Sexuality, Race, and Socioeconomic Status

In this article, we examine intersections of race, sexuality, and socioeconomic status (SES) in people’s experiences with police contact in Chicago. Utilizing representative data concerning police contact as well as sexual and racial identification, we examine variations in police contact for respondents occupying different racial, sexual, and economic social locations. In so doing, we examine the case of an urban area often lauded for progress in sexual minority rights to quantitatively evaluate disparities in the experiences of sexual minorities occupying different racial and sexual positions in society. In conclusion, we draw out implications for (1) developing intersectional analyses of contemporary sexual minority experience; (2) understanding the ways race, sexuality, and SES shape experiences with police contact even in settings deemed more progressive than the broader society; and (3) the ways in which incorporating an analysis of bisexuality into mainstream social science complicates existing assumptions and theories.