scholarly journals Hydraulic constraints of reproduction do not explain sexual dimorphism in the genus Leucadendron (Proteaceae)

2017 ◽  
Author(s):  
Adam B. Roddy ◽  
Justin van Blerk ◽  
Jeremy J. Midgley ◽  
Adam G. West
Keyword(s):  
Sexual Dimorphism ◽  
Fire Frequency ◽  
Sexually Dimorphic ◽  
Hydraulic Efficiency ◽  
Costs Of Reproduction ◽  
Dioecious Species ◽  
Shoot Architecture ◽  
Males And Females ◽  
And Function ◽  
In Fire

AbstractBecause of the importance of reproduction in plant life history, the physiological costs of reproduction often influence vegetative structure and function. In dioecious species, these effects can be quite obvious, as different costs of male and female reproductive functions are entirely separated among different individuals in a population. In fire-prone ecosystems, in which recruitment is driven by fire frequency, many plants will maintain their seeds in the canopy, only to be released after a fire. The dioecious genus Leucadendron is a notable case of this, as females can maintain their seed cones for years, and, even more interestingly, species in the genus differ substantially in the degree to which males and females are sexually dimorphic. A recent study (Harris and Pannell 2010) argued that the hydraulic costs of maintaining seed cones for many years would effect the degree of sexual dimorphism among species. However, this assumed that shoot hydraulic architecture would be related to traits exhibiting sexual dimorphism. Here we explicitly test this hypothesis on two Leucadendron species. We found (1) that metrics of branch ramification used in the previous study to characterize dimorphism do not conform to known scaling relationships and (2) that sexual dimorphism in shoot architecture has no effect on hydraulic efficiency. Both of these results seriously question the pattern described by Harris and Pannell (2010) and suggest that the hydraulic costs of prolonged seed retention in Leucadendron do not significantly affect branch architecture.

scholarly journals Sexual dimorphism in a top predator ( Notophthalmus viridescens ) drives aquatic prey community assembly

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181717 ◽  
Author(s):  
Denon Start ◽  
Stephen De Lisle
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Intraspecific Variation ◽  
Structure And Function ◽  
Sexually Dimorphic ◽  
Ecological Communities ◽  
Top Predator ◽  
Aquatic Mesocosms ◽  
And Function ◽  
The Impact

Intraspecific variation can have important consequences for the structure and function of ecological communities, and serves to link community ecology to evolutionary processes. Differences between the sexes are an overwhelmingly common form of intraspecific variation, but its community-level consequences have never been experimentally investigated. Here, we manipulate the sex ratio of a sexually dimorphic predacious newt in aquatic mesocosms, then track their impact on prey communities. Female and male newts preferentially forage in the benthic and pelagic zones, respectively, causing corresponding reductions in prey abundances in those habitats. Sex ratio differences also explained a large proportion (33%) of differences in the composition of entire pond communities. Ultimately, we demonstrate the impact of known patterns of sexual dimorphism in a predator on its prey, uncovering overlooked links between evolutionary adaptation and the structure of contemporary communities. Given the extreme prevalence of sexual dimorphism, we argue that the independent evolution of the sexes will often have important consequences for ecological communities.

scholarly journals Ramification has little impact on shoot hydraulic efficiency in the sexually dimorphic genus Leucadendron (Proteaceae)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6835 ◽  
Author(s):  
Adam B. Roddy ◽  
Justin J. van Blerk ◽  
Jeremy J. Midgley ◽  
Adam G. West
Keyword(s):  
Leaf Area ◽  
Hydraulic Resistance ◽  
Leaf Traits ◽  
Sexually Dimorphic ◽  
Hydraulic Efficiency ◽  
Cross Sectional ◽  
In Series ◽  
Males And Females ◽  
Morphological Differences ◽  
The Impact

Despite the diversity of branching architectures in plants, the impact of this morphological variation on hydraulic efficiency has been poorly studied. Branch junctions are commonly thought to be points of high hydraulic resistance, but adjustments in leaf area or xylem conduit abundance or dimensions could compensate for the additional hydraulic resistance of nodal junctions at the level of the entire shoot. Here we used the sexually dimorphic genus Leucadendron (Proteaceae) to test whether variation in branch ramification impacts shoot hydraulic efficiency. We found that branch ramification was related to leaf traits via Corner’s rules such that more highly ramified shoots had smaller leaves, but that branch ramification had little consistent impact on shoot hydraulic efficiency, whether measured on a leaf area or stem cross-sectional area basis. These results suggest that the presumed increase in resistance associated with branching nodes can be compensated by other adjustments at the shoot level (e.g. leaf area adjustments, increased ramification to add additional branches in parallel rather than in series) that maintain hydraulic efficiency at the level of the entire shoot. Despite large morphological differences between males and females in the genus Leucadendron, which are due to differences in pollination and reproduction between the sexes, the physiological differences between males and females are minimal.

scholarly journals Rheotaxis Response Based on Sexual Dimorphism in the Green Swordtail Fish, Xiphophorus hellerii

Biota ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 128-139
Author(s):  
Muhammad Irsyad Abiyusfi Ghafari ◽  
Vita Fitrianti
Keyword(s):  
Sexual Dimorphism ◽  
Gravid Female ◽  
Adult Males ◽  
Dioecious Species ◽  
Swordtail Fish ◽  
Xiphophorus Hellerii ◽  
Males And Females ◽  
Morphological Differences ◽  
Gravid Females ◽  
The Individual

Morphological distinctions between males and females of a species are referred to by sexual dimorphism. It may result from various selection pressures affecting either sex or both and may occur in any dioecious species, including Green Swordtail fish, which are sexually reproductive. This study examined the different rheotaxis responses of Xiphophorus hellerii based on different sexes and morphological features. We analyzed ten adult males, ten gravid females, and ten non-gravid females of Xiphophorus helleri collected down the river and transferred into the column. We counted the number of the individual that performed positive rheotaxis (+), negative rheotaxis (-), and indifference response (0). The result showed different rheotaxis responses shown by male, non-gravid female, and gravid female X. hellerii. The highest percentage of positive rheotaxis response (movement against the current) was shown by non-gravid female X. hellerii, reaching up to 89%. Morphological differences between male, non-gravid female, and gravid female X. hellerii appear to affect the orientation and ability of X. hellerii in giving response against current and certainly has an impact on their survival in nature.

scholarly journals First Case of Dual Size Asymmetry in an Identical Arthropod Organ: Different Asymmetries of the Combative (Sexual) and Cutting (Non-Sexual) Parts of Mandibles in the Horned Stored-Product Beetle Gnatocerus cornutus (Fabricius, 1798)

Insects ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 151 ◽  
Author(s):  
Tomas Vendl ◽  
Vaclav Stejskal ◽  
Radek Aulicky
Keyword(s):  
Sexual Dimorphism ◽  
Regulatory Mechanisms ◽  
Directional Asymmetry ◽  
Sexually Dimorphic ◽  
First Case ◽  
Males And Females ◽  
Long Life ◽  
High Degree ◽  
Size Asymmetry ◽  
Single Organ

Although it is known that separate insect body structures may be asymmetrical within one species, the different functional asymmetries within a single organ as a result of differential selective regimes have not been described. Based on microscopic measurements and SEM photography, we examined the size, shape and asymmetry of the mandibular structures of males and females of the sexually dimorphic broad-horned flour beetle, Gnatocerus cornutus (Tenebrionidae, Coleoptera). It was found that sexual dimorphism only manifests in certain outgrowth parts (horns) of male mandibles, while the remaining cutting parts of the mandibles hold identical morphologies for both sexes. A more interesting finding—since this is the first published case of dual functionally selected asymmetry in an identical arthropod organ—was that the cutting part of the male mandible exhibited directional asymmetry, whereas the outgrowth horn part of the mandible showed a high degree of symmetry. Moreover, there was no relationship between the size and asymmetry of horns. The results indicate different regulatory mechanisms of sexually selected combative horns and the food-functional, more conservative (constrained by hard food and adult long life) cutting parts of mandibles.

scholarly journals Genome assembly and methylome analysis of the white wax scale insect provides insight into sexual differentiation of metamorphosis in hexapods

2021 ◽  
Author(s):  
Hang Chen ◽  
Qin Lu ◽  
Xiaoming Chen ◽  
Xiaofei Ling ◽  
Pengfei Liu ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
De Novo ◽  
Pupal Stage ◽  
Gene Families ◽  
Scale Insect ◽  
Scale Insects ◽  
Sexually Dimorphic ◽  
Methylome Analysis ◽  
Males And Females ◽  
Methylation Patterns

Scale insects are hemimetabolous, showing “incomplete” metamorphosis and no true pupal stage. Ericerus pela, commonly known as the white wax scale insect (hereafter, WWS), is a wax-producing insect found in Asia and Europe. WWS displays dramatic sexual dimorphism, with notably different metamorphic fates in males and females. Males develop into winged adults, while females are neotenic and maintain a nymph-like appearance, which are flightless and remain stationary. Here we report the de novo assembly of the WWS genome with its size of 638.30 Mb (69.68Mb for scaffold N50) by PacBio sequencing and Hi-C. From these data, we constructed a robust phylogenetic analysis of 24,923 gene families from 16 representative insect genomes, which indicates that holometabola evolved from incomplete metamorphosis insects in the Late Carboniferous, about 50 million years earlier than previously thought. To study the distinct development of males and females, we analyzed the methylome landscape in either sex. Surprisingly, WWS displayed high levels of methylation (4.42% for males) when compared to other insects. We observed differential methylation patterns for genes involved in steroid and sesquiterpenoids production as well as related fatty acid metabolism pathways. We show here that both males and females exhibit distinct titer profiles for ecdysone, the principal insect steroid hormone, and juvenile hormone (a sesquiterpenoid), suggesting that these hormones are the primary drivers of sexually dimorphic features. Our results provide a comprehensive genomic and epigenomic resource of scale insects that provide new insights into the evolution of metamorphosis and sexual dimorphism in insects.

Sex-related Differences in Gene Expression in Salivary Glands of BALB/c Mice

2005 ◽  
Vol 84 (2) ◽  
pp. 160-165 ◽  
Author(s):  
N.S. Treister ◽  
S.M. Richards ◽  
M.J. Lombardi ◽  
P. Rowley ◽  
R.V. Jensen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sexual Dimorphism ◽  
Salivary Glands ◽  
Structure And Function ◽  
Differentially Expressed ◽  
Male And Female ◽  
Tissue Specific ◽  
Total Rna ◽  
Males And Females ◽  
And Function

Sex-related differences exist in the structure and function of the major glands in a variety of species. Moreover, many of these variations appear to be unique to each tissue. We hypothesized that this sexual dimorphism is due, at least in part, to gland-specific differences in gene expression between males and females. Glands were collected from male and female BALB/c mice (n = 5/sex/experiment), and total RNA was isolated. Samples were analyzed for differentially expressed mRNAs with CodeLink microarrays, and data were evaluated by GeneSifter. Our results demonstrate that significant (P < 0.05) sex-related differences exist in the expression of numerous genes in the major salivary glands, and many of these differences were tissue-specific. These findings support our hypothesis that sex-related differences in the salivary glands are due, at least in part, to tissue-specific variations in gene expression.

Reproduction and development

2012 ◽  
Keyword(s):  
Sexual Dimorphism ◽  
Brain Structures ◽  
Sexual Differences ◽  
Tissue Type ◽  
Endocrine Control ◽  
Human Form ◽  
Form And Function ◽  
Sexual Characteristics ◽  
Males And Females ◽  
And Function

Reproduction and development are large topics, knowledge of which underpins several medical specialities including sexual health, fertility, gynaecology, urology, reproductive endocrinology, obstetrics, and neonatology. Doctors need to know the structure, function, and endocrine control of both male and female systems in order to diagnose and manage conditions specific to either male or female organs, as well as conditions such as impotence and infertility. Not surprisingly, the reproductive system is the only body system that shows major differences in both structure and function between males and females. However, sexual differences go beyond the primary sexual characteristics present at birth and the secondary sexual characteristics that emerge under the influence of sex hormones at puberty. Sexual dimorphism in some brain structures commences at an early age, and differences in the endocrine profiles of males and females produce characteristic changes in morphology, physiology, and behaviour that go beyond simple sexual dimorphism to affect many aspects of life, including sexual differences in susceptibility to disease and the longer life expectancy of women as compared to men that is seen around the world. Whether these differences, mainly beneficial to women, are because females are ‘biologically superior’ or because of a complex mix of genetic, behavioural, and social factors is a matter for discussion and research. Some knowledge of embryology is important to every medical student. As a minimum it provides explanations for the congenital malformations and their consequences that are encountered in many areas of clinical practice. Deeper knowledge will assist those seeking real insights into the structure of the human body. It is the study of embryological development and the knowledge of how each tissue type arises, how one tissue meets another, and how tissues move and change shape during development that explains the relations between tissues and organs in the adult human form. Achieving a full understanding of the dynamics of the formation of the body’s organs and tissues is demanding, but it can replace some of the rote learning of anatomical structures, familiar to many students, with a deeper understanding of form and function.

Sexual dimorphism of messenger RNA isolated from neonatal rat brain

1986 ◽  
Vol 109 (1) ◽  
pp. 23-NP ◽  
Author(s):  
I. M. Adcock ◽  
B. D. Greenstein
Keyword(s):  
Sexual Dimorphism ◽  
Rat Brain ◽  
Limbic System ◽  
Messenger Rna ◽  
Neonatal Rat ◽  
Transcriptional Level ◽  
Sexually Dimorphic ◽  
Clear Cut ◽  
And Function

ABSTRACT The rat brain is sexually dimorphic with respect to structure and function, and there is evidence that these differences are effected in the fetus through changes in protein synthesis, some of which may result from the intervention of gonadal steroids. To investigate this, messenger RNA (mRNA) from the limbic system and cerebellum of neonatal rats was prepared, translated in a rabbit reticulocyte system in vitro and the products were analysed by two-dimensional electrophoresis and fluorography. Some of the results were further analysed using image analysis. There was a striking sexual dimorphism in the patterns of incorporation of [35S]methionine into proteins using mRNA from the limbic system, in that groups of proteins were apparently present in male-but not in female-derived fluorograms and vice versa. One protein, tentatively identified from its coordinates as α-tubulin, was more abundant in male-derived fluorograms. Although there were no clear-cut qualitative sex differences using mRNA derived from the cerebellum, that derived from the male cerebellum appeared to be consistently more active. These results provide direct evidence for a sexual dimorphism at the transcriptional level in the neonatal limbic system of the rat. J. Endocr. (1986) 109, 23–28

scholarly journals Differences in Pelvic Fin Length Represent Sexual Dimorphism in Utah Chub (Gila atraria)

2014 ◽  
Vol 7 (1) ◽  
pp. 42-45 ◽  
Author(s):  
Mark C. Belk ◽  
Scott Bird ◽  
Mehmet Cemal Oguz ◽  
Jerald B. Johnson
Keyword(s):  
Body Size ◽  
Sexual Dimorphism ◽  
Cyprinid Fish ◽  
Sexually Dimorphic ◽  
Adaptive Function ◽  
Males And Females ◽  
The Difference ◽  
Sexually Mature ◽  
Fin Length ◽  
Pelvic Fin

The cyprinid fish Gila atraria Girard (Utah chub) is generally considered a sexually monomorphic species. However, prior observations revealed variation in pelvic fin length within populations that appears sexually dimorphic. We measured the relative pelvic fin length of 419 sexually mature Utah chub from 8 different locations to determine the magnitude and generality of this apparent dimorphism. Pelvic fin length in G. atraria differs between sexes by about 10% on average; males have longer pelvic fins than females. The dimorphism is general across all locations, but it is not related to body size. Magnitude of the dimorphism varies by predation environment – the difference between males and females is slightly greater in low predation environments. We find no evidence for an adaptive function for this dimorphism; however, it does provide an efficient mechanism for determining sex without dissection.

scholarly journals Sexual dimorphism in the electric knifefish, Gymnorhamphichthys rondoni (Rhamphichthyidae: Gymnotiformes)

2019 ◽  
Vol 49 (3) ◽  
pp. 213-220
Author(s):  
Elisa Queiroz GARCIA ◽  
Jansen ZUANON
Keyword(s):  
Sexual Dimorphism ◽  
Body Height ◽  
Principal Component ◽  
The Body ◽  
Vertical Line ◽  
Head Length ◽  
Genital Papilla ◽  
Adult Males ◽  
Dioecious Species ◽  
Males And Females

ABSTRACT Sexual dimorfism refers to morphological differences between males and females of a species. It may be a result of different selection pressures acting on either or both sexes and may occur in any sexually-reproducing dioecious species, including fishes. We analyzed 63 females and 63 adult males of Gymnorhamphichthys rondoni (Gymnotiformes) collected by us or deposited in museum collections. Sex was identified through abdominal dissection. We measured length from snout to posterior end of anal-fin, anal-fin length, distance from anus to anal-fin origin, distance from genital papilla to anal-fin origin, body width at beginning of anal-fin, and head length. Morphometric data submitted to a Principal Component Analysis (PCA) grouped males and females according to variables related to body size (along the first component) and to head length and body height along the second and third components. Females were larger than males, whereas males had proportionally larger heads and higher bodies than females. The urogenital papilla of males and females showed differences in shape, size and relative position on the body. The female papilla was elongated horizontally, larger than that of males, and was located on a vertical line below the eye, while the papilla of the males was vertically elongated and located on a vertical line below the operculum. To our knowledge, this is the first recorded case of sexual dimorphism in a species of Rhamphichthyidae, a condition that is now known in all the currently recognized families of Gymnotiformes.

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