Copulation, mating system and sexual dimorphism in an Australian millipede, Cladethosoma clarum

2010 ◽  
Vol 58 (2) ◽  
pp. 127 ◽  
Author(s):  
Melissah Rowe
Keyword(s):  
Sexual Dimorphism ◽  
Mating System ◽  
Body Mass ◽  
Multiple Mating ◽  
Mate Location ◽  
Location Strategy ◽  
Leg Length ◽  
Body Width ◽  
Opposite Sex ◽  
Copulation Behaviour

Investigations of millipede mating dynamics have focussed primarily on Old World or North American species. In contrast, data for the diverse and abundant polydesmid millipedes of Australia are lacking. Here I examine copulation, behaviour and sexual dimorphism in an Australian millipede, Cladethosoma clarum. In this species, copula position is best described as ‘in parallel’. Both females and males mated with two or more individuals of the opposite sex, and average copulation duration was 4.7 min. Behavioural observations revealed differences between the sexes in patterns of behaviour. Specifically, females devoted most of their time to feeding, whereas males were more mobile and were observed walking more often than females. The sexes also exhibited marked sexual dimorphism in that females exhibited greater body width and body mass compared with males, whereas males had longer legs relative to females. In millipedes, longer legs allow an individual to walk faster. Consequently, male C. clarum appear to be capable of relatively rapid locomotion. As Australian millipede densities are spatially unpredictable, the increased mobility of males likely reflects an active mate-location strategy. Furthermore, the occurrence of multiple mating by females suggests that male leg length may have evolved as an adaptation for rapid mate location under scramble competition polygyny.

scholarly journals Sexual conflict drives micro- and macroevolution of sexual dimorphism in immunity

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Basabi Bagchi ◽  
Quentin Corbel ◽  
Imroze Khan ◽  
Ellen Payne ◽  
Devshuvam Banerji ◽  
...  
Keyword(s):  
Sex Differences ◽  
Sexual Dimorphism ◽  
Mating System ◽  
Sexual Conflict ◽  
Experimental Evolution ◽  
Parasitic Infections ◽  
Pathogen Dynamics ◽  
Trade Offs ◽  
Host Pathogen ◽  
Seed Beetles

Abstract Background Sexual dimorphism in immunity is believed to reflect sex differences in reproductive strategies and trade-offs between competing life history demands. Sexual selection can have major effects on mating rates and sex-specific costs of mating and may thereby influence sex differences in immunity as well as associated host–pathogen dynamics. Yet, experimental evidence linking the mating system to evolved sexual dimorphism in immunity are scarce and the direct effects of mating rate on immunity are not well established. Here, we use transcriptomic analyses, experimental evolution and phylogenetic comparative methods to study the association between the mating system and sexual dimorphism in immunity in seed beetles, where mating causes internal injuries in females. Results We demonstrate that female phenoloxidase (PO) activity, involved in wound healing and defence against parasitic infections, is elevated relative to males. This difference is accompanied by concomitant sex differences in the expression of genes in the prophenoloxidase activating cascade. We document substantial phenotypic plasticity in female PO activity in response to mating and show that experimental evolution under enforced monogamy (resulting in low remating rates and reduced sexual conflict relative to natural polygamy) rapidly decreases female (but not male) PO activity. Moreover, monogamous females had evolved increased tolerance to bacterial infection unrelated to mating, implying that female responses to costly mating may trade off with other aspects of immune defence, an hypothesis which broadly accords with the documented sex differences in gene expression. Finally, female (but not male) PO activity shows correlated evolution with the perceived harmfulness of male genitalia across 12 species of seed beetles, suggesting that sexual conflict has a significant influence on sexual dimorphisms in immunity in this group of insects. Conclusions Our study provides insights into the links between sexual conflict and sexual dimorphism in immunity and suggests that selection pressures moulded by mating interactions can lead to a sex-specific mosaic of immune responses with important implications for host–pathogen dynamics in sexually reproducing organisms.

Ideal body image for the opposite sex and its association with body mass index

2021 ◽  
pp. 1-9
Author(s):  
María Eugenia Ibáñez-Zamacona ◽  
Alaitz Poveda ◽  
Esther Rebato
Keyword(s):  
Body Mass Index ◽  
Body Image ◽  
Body Mass ◽  
Normal Weight ◽  
Age Group ◽  
Younger Age ◽  
Opposite Sex ◽  
Ideal Body Image ◽  
Ideal Body ◽  
Spearman’S Correlation

Abstract This research studied the preferences reported by women and men about their Ideal Body Image for the Opposite Sex (IBIOS), and its association with body mass index (BMI). It also analysed the preferences of each sex for a woman’s ideal body image (W-IBI) and a man’s ideal body image (M-IBI). A total of 450 participants aged 18–70 years with different weights were studied. Their IBIOS was assessed using standard figural stimuli. The sample was divided in four groups by sex and age (<45 years; ≥45 years). Sex and age differences in IBIOS, as well as sex differences in the preferences for a woman’s ideal body image (W-IBI) and a man’s ideal body image (M-IBI), were tested using a non-parametric Mann-Whitney U test. The association between IBIOS and BMI was analysed using Spearman’s correlation. In all groups, the most chosen silhouette as IBIOS was number 4. In the under-45 years group, women chose bigger silhouettes for the opposite sex than men did (p<0.05). In this age group women chose as ideal smaller silhouettes for the female body than men did (p<0.01). In addition, women and men in the younger age group and with normal weight chose smaller silhouettes, while those who were overweight or obese selected larger silhouettes (p<0.001). Age was found to be a relevant factor in IBIOS preferences, and in the association between IBIOS and nutritional status as measured by BMI, which was only observed to be significant in the younger age group.

scholarly journals Prevalence and Characteristics of Back Pain in Children and Adolescents from the Region of Murcia (Spain): ISQUIOS Programme

2022 ◽  
Vol 19 (2) ◽  
pp. 946
Author(s):  
María Teresa Martínez-Romero ◽  
Antonio Cejudo ◽  
Pilar Sainz de Baranda
Keyword(s):  
Back Pain ◽  
Body Mass ◽  
Ad Hoc ◽  
Pubertal Development ◽  
Body Height ◽  
Maturity Stage ◽  
Leg Length ◽  
Anthropometric Measures ◽  
School Aged Children ◽  
The Past

Puberty is a vulnerable period for musculoskeletal disorders due to the existence of a wide inter-individual variation in growth and development. The main objective of the present study was to describe the prevalence of back pain (BP) in the past year and month in school-aged children according to sex, age, maturity status, body mass index (BMI) and pain characteristics. This study involved 513 students aged between 9 and 16 years. Anthropometric measures were recorded to calculate the maturity stage of the students using a regression equation comprising measures for age, body mass, body height, sitting height and leg length. An ad hoc questionnaire composed of eight questions was used to describe BP prevalence in school-aged children. The results showed that the prevalence of BP in school-aged children was observed in 35.1% over the last year (45% boys and 55% girls), and 17.3% (40.4% boys and 59.6% girls, with an association found between female sex and BP) in the last month. The prevalence of back pain in the past year and month was higher the older the students were, or the more pubertal development they had experienced. The prevalence of BP in the last year was also higher in those with overweight or obesity. After adjustment for sex, there was an association between BP and older age and higher BMI in boys and an association between BP and higher pubertal development in girls. In summary, the present study showed that the prevalence of BP was related to the maturity stage and weight of the participants, with different prevalence patterns found according to sex.

Sexual dimorphism, mating system, and effect of phylogeny in De Brazza's monkey (Cercopithecus neglectus)

1987 ◽  
Vol 13 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Walter Leutenegger ◽  
Gabriele Lubach
Keyword(s):  
Sexual Dimorphism ◽  
Mating System ◽  
Cercopithecus Neglectus

Sexual dimorphism in leg length among orb-weaving spiders: a possible role for sexual cannibalism

1990 ◽  
Vol 222 (3) ◽  
pp. 455-470 ◽  
Author(s):  
M. A. Elgar ◽  
N. Ghaffar ◽  
A. F. Read
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Cannibalism ◽  
Leg Length

Factors Affecting Peak Vertical Ground Reaction Forces in Running

1986 ◽  
Vol 2 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Edward C. Frederick ◽  
John L. Hagy
Keyword(s):  
Body Mass ◽  
Stride Length ◽  
Reaction Force ◽  
Step Length ◽  
Leg Length ◽  
Vertical Ground Reaction Force ◽  
Anthropometric Parameters ◽  
Factors Affecting ◽  
Reaction Forces ◽  
Vertical Ground

Nine subjects (6 males, 3 females) ranging in body mass from 90.9 to 45.5 kg ran repeated trials across a force platform while being filmed at 50 fps. The subjects ran five barefooted trials at each of three speeds: 3.35, 3.83, and 4.47 m · s−1. Force data were collected on-line and analyzed for the magnitude and temporal characteristics of the initial impact (Fz1) peak and the active (Fz2) peak of vertical ground reaction force (VGRF). Multiple regression and correlation analysis were used to study the relationship between the magnitudes of these kinetic data and kinematic and anthropometric data taken from the film and from measurements of the subjects. The results support the general conclusion that speed and, indirectly, body mass are significant effectors of the magnitudes of Fz1. In addition, other factors that correlate significantly with Fz1 are reciprocal ponderal index (RPI) and stature; half-stride length, step length, leg length, and vertical hip excursion during a half-stride cycle; and hip offset, contact angle, and dorsiflexion angle at contact. Body mass correlates highly with Fz2 (r = 0.95). Other significant factors correlating with Fz2 are RPI, stature, vertical hip excursion, dorsiflexion angle, hip offset, half-stride length, and step length. These data support earlier findings that speed and the effective mass of the leg at contact are important effectors of the magnitude of Fzl. In addition, the kinematic and anthropometric parameters that contribute significantly to the variability in Fzl and F are generally cross-correlated with body size and/or running speed.

Body size, sexual dimorphism, and seasonal mass fluctuations in a larger sika deer subspecies, the Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884)

2001 ◽  
Vol 79 (1) ◽  
pp. 154-159 ◽  
Author(s):  
Masatsugu Suzuki ◽  
Manabu Onuma ◽  
Mayumi Yokoyama ◽  
Koich Kaji ◽  
Masami Yamanaka ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Body Mass ◽  
Body Length ◽  
Sika Deer ◽  
Cervus Nippon ◽  
Total Body Mass ◽  
Foot Length ◽  
Hind Foot ◽  
Total Body ◽  
Cervus Nippon Yesoensis

Measurements of shoulder height, body length, hind-foot length, and total body mass were collected from 309 Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) (115 males and 194 females) and analyzed statistically for sexual dimorphism and seasonal body mass fluctuations. The von Bertalanffy equation was fitted to the growth curves that resulted. Asymptotic shoulder height, body length, and hind-foot length were 106.2, 112.6, and 52.9 cm in males and 94.8, 103.9, and 49.4 cm in females, respectively. Total body mass showed distinct seasonal fluctuations, ranging between 102.8 and 151.0 kg in adult males and 68.0 and 99.8 kg in adult females. Male/female ratios in shoulder height, body length, hind-foot length, and total mass were 1.12, 1.08, 1.07, and 1.51, respectively. These results indicate that the Hokkaido sika deer is one of the largest subspecies, at least in skeleton size. A larger body and longer hind foot would seem to be evolutionary adaptations to Hokkaido's cold, snowy environment.

Estrogen receptor regulation of pulmonary alveolar dimensions: alveolar sexual dimorphism in mice

2006 ◽  
Vol 290 (5) ◽  
pp. L866-L870 ◽  
Author(s):  
Donald Massaro ◽  
Gloria DeCarlo Massaro
Keyword(s):  
Estrogen Receptor ◽  
Sexual Dimorphism ◽  
Surface Area ◽  
Body Mass ◽  
Female Rats ◽  
Female Mice ◽  
Alveolar Surface Area ◽  
Rats And Mice ◽  
Alveolar Surface ◽  
Respective Species

Female rats and mice have smaller and, per body mass (BM), more alveoli and alveolar surface area (Sa) than males of their respective species. This sexual dimorphism becomes apparent about the time of sexual maturity. It is prevented in rats (not tested in mice) by ovariectomy at age 3 wk. In female mice, estrogen receptor (ER)-α and ER-β are required for formation of alveoli of appropriate size and number. We now report the average volume of an alveolus (v̄a) and the number of alveoli per body mass (Na/BM) were not statistically different between ER-α−/− and wild type (wt) males. However, the combination of a larger value for v̄a and a smaller value for Na/BM, though neither parameter achieved a statistically significant intergroup difference, resulted in a statistically significant lower Sa/BM in ER-α−/− males compared with wt males. In ER-β−/− males, v̄a was bigger and Na/BM and Sa/BM were lower compared with wt males. Wt males had larger alveoli and lower Na/BM and Sa/BM than wt females. The wt sexual dimorphism of v̄a, Na/BM, and Sa/BM was absent in ER-α−/− mice. Alveolar size did not differ between ER-β−/− females and males but Na/BM and Sa/BM were greater in ER-β−/− females than in ER-β−/− males. The results in male mice, with prior findings in female mice, 1) demonstrate estrogen receptors have a smaller effect on alveolar dimensions in male than female mice, 2) show ER-α and ER-β are required for the sexual dimorphism of alveolar size, and 3) show ER-α is needed for the sexual dimorphism of body mass-specific alveolar number and surface area.

Sexual dimorphism of the major chela and sex ratio as indicators of the mating system in the estuarine snapping shrimp Alpheus colombiensis Wicksten, 1988 (Decapoda: Caridea: Alpheidae)

2020 ◽  
Vol 40 (6) ◽  
pp. 649-656
Author(s):  
Juan C Azofeifa-Solano ◽  
Jeffrey A Sibaja-Cordero ◽  
Ingo S Wehrtmann
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Mating System ◽  
Mate Guarding ◽  
Female Size ◽  
Monogamous Species ◽  
Low Degree ◽  
Adult Sex Ratio ◽  
Snapping Shrimps

Abstract The sexual selection over traits that favor access to mating partners could promote the emergence of sexual dimorphism when the pressure is different between sexes. Monogamous species are considered to have a low degree of sexual dimorphism. The highly diverse snapping shrimps are usually regarded as monogamous, but the mating system has been studied only in few species. We aimed to provide insights into the mating system and sexual dimorphism of Alpheus colombiensisWicksten, 1988. The adult sex ratio was female biased, and solitary ovigerous females were found, suggesting a temporary mate guarding type of mating system. Our results also revealed sexual dimorphism on the snapping claw, which is larger in males than in females. The male’s snapping claw is probably under sexual selection, which can be mediated by male-male competition or female choice. We also estimated the A. colombiensis female size at maturity at 5.2 ± 0.76 mm. Our results contradict the common idea that snapping shrimps are monogamous species, and support that A. colombiensis probably have a temporary mate guarding (e.g., males can sexually interact with more than one female, in opposition to sexual monogamy). This study also sustains the growing evidence that alpheid shrimps display snapping claw sexual dimorphism.

Sexual Dimorphism, Mating System and Body Size in New World Blackbirds (Icterinae)

Evolution ◽  
1992 ◽  
Vol 46 (6) ◽  
pp. 1621 ◽  
Author(s):  
Michael S. Webster
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Mating System ◽  
New World
Sign in / Sign up

Export Citation Format

Share Document