scholarly journals Low siring success of females with an acquired male function illustrates the legacy of sexual dimorphism in constraining the breakdown of dioecy

2019 ◽  
Vol 22 (3) ◽  
pp. 486-497 ◽  
Author(s):  
Luis Santos del Blanco ◽  
Eleri Tudor ◽  
John R. Pannell
Keyword(s):  
Sexual Dimorphism ◽  
Male Function ◽  
Siring Success

scholarly journals A ghost of dioecy past and the legacy of sexual dimorphism: low siring success of hermaphrodites after the breakdown of dioecy

2018 ◽  
Author(s):  
Luis Santos del Blanco ◽  
Eleri Tudor ◽  
John R. Pannell
Keyword(s):  
Sexual Dimorphism ◽  
Sexual Function ◽  
Empirical Support ◽  
Evolutionary Models ◽  
Evolutionary Transitions ◽  
Sexual Specialization ◽  
Siring Success ◽  
Mercurialis Annua

AbstractEvolutionary transitions from dioecy to hermaphroditism must overcome the inertia of sexual dimorphism because modified males or females will express the opposite sexual function for which their phenotypes have been optimized. We tested this prediction by comparing the siring success of female-derived hermaphrodites of the plant Mercurialis annua with males and hermaphrodites that present a male-like inflorescence. We found that pollen dispersed by female-derived hermaphrodites was about a third poorer at siring outcross offspring than that from hermaphrodites with male-like inflorescences, illustrating the notion that a ‘ghost of dioecy past’ compromises the fitness of derived hermaphrodites in outcrossing populations. We conclude that whereas dioecy might evolve from hermaphroditism by conferring upon individuals certain benefits of sexual specialization, reversals from dioecy to hermaphroditism must often be limited to situations in which outcrossing cannot be maintained and inbreeding is favored. Our study provides novel empirical support for evolutionary models for the breakdown of dioecy.

scholarly journals La pesadilla de lindley - la biología sexual de catasetum y cycnoches

Lankesteriana ◽  
2013 ◽  
Author(s):  
Günter Gerlach
Keyword(s):  
Gas Chromatography ◽  
Sexual Dimorphism ◽  
Common Knowledge ◽  
Botanical Garden ◽  
Negative Experience ◽  
Male Function ◽  
Male Flowers ◽  
Viable Seeds ◽  
Male To Female ◽  
Female Flowers

The sexual dimorphism of the genera Catasetum and Cycnoches is now common knowledge to orchid growers and investigators. Female flowers of Catasetum are all non-resupinate with a hooded lip, whereas the male flowers can be non-resupinate with a hooded lip or resupinate with a differently shaped lip, depending on the species. Only with male flowers present can the species of a Catasetum can be determined. In Cycnoches, flowers of both sexes are resupinate with a slender and long, curved column, resembling a swan’s neck. The lip of male flowers of C. sect. Heteranthae is provided with finger-like projections, but female flowers of that section and those of C. sect. Cycnoches have an entire lip. Female flowers of both genera observed in the Botanical Garden of Munich bear pollinaria, but they are without any function. Slight movements of the female inflorescences of Catasetum cause the pollinaria to fall off, and as a result their presence is often overlooked. In female pollinaria of Catasetum the caudicles are absent, making pollination impossible in nature. Their pollen is germinable, and application of the pollinia to the stigma of the same flower yields viable seeds. The seldomobserved intermediate forms have a stigmatic cavity as in the male flowers. Their pollinaria are similar to those of the female flowers, so they are also non-functional. They do not serve either as males or females. In female Cycnoches, the anther cap does not fall off, so preventing pollination by such a pollinarium. The pollinia are encapsulated by the anther cap and so cannot come into contact with the stigma of another flower. Here, too, germination tests of the female pollen were positive. It is suspected that selfing of the female flowers here also will result in viable seeds. In both cases the female flowers are true hermaphrodites, but because of their limited male function one should think of them as functional female flowers. Male flowers, however, do not develop precursors of ovules, and a stigma is not present. Given the different flower morphologies and the pollination processes, one assumes that the floral fragrances should differ among the sexes of Catasetum flowers. The battered pollinator will remember the negative experience with the male flowers. So different fragrances in the female flowers would be the way out of this dilemma. Floral fragrances of five Catasetum species and two Cycnoches species were investigated by gas chromatography. Only weak differences in the fragrance composition of the separate sexes were detected, begging several questions. What are the forces driving the pollinator from male to female flowers? Is the weight of the pollinarium sufficient to explain avoidance of the male flowers? Does the bee still remember the disagreeable episode? Is identification effected only by visual senses?

RHYNCHOLITES AND THE PROBLEM OF NARROW AND BROAD CONCEPTION OF TAXONS

2018 ◽  
pp. 12-17 ◽  
Author(s):  
I. R. Khuzina ◽  
V. N. Komarov
Keyword(s):  
Sexual Dimorphism ◽  
Morphological Characteristics ◽  
Mass Scale ◽  
Individual Variability ◽  
Point Of View ◽  
The Other ◽  
New Taxon ◽  
Artificial System ◽  
Broad Understanding

The paper considers a point of view, based on the conception of the broad understanding of taxons. According to this point of view, rhyncholites of the subgenus Dentatobeccus and Microbeccus are accepted to be synonymous with the genus Rhynchoteuthis, and subgenus Romanovichella is considered to be synonymous with the genus Palaeoteuthis. The criteria, exercising influence on the different approaches to the classification of rhyncholites, have been analyzed (such as age and individual variability, sexual dimorphism, pathological and teratological features, degree of disintegration of material), underestimation of which can lead to inaccuracy. Divestment of the subgenuses Dentatobeccus, Microbeccus and Romanovichella, possessing very bright morphological characteristics, to have an independent status and denomination to their synonyms, has been noted to be unjustified. An artificial system (any suggested variant) with all its minuses is a single probable system for rhyncholites. The main criteria, minimizing its negative sides and proving the separation of the new taxon, is an available mass-scale material. The narrow understanding of the genus, used in sensible limits, has been underlined to simplify the problem of the passing the view about the genus to the other investigators and recognition of rhyncholites for the practical tasks.

Observation on the breeding biology of Polypedates teraiensis (Dubois, 1987) (Amphibia: Rhacophoridae)

2017 ◽  
Vol 17 (1) ◽  
pp. 25-32
Author(s):  
Jacinta Lalchhanhimi ◽  
Lalremsanga H.T.
Keyword(s):  
Sexual Dimorphism ◽  
Breeding Season ◽  
Sound Production ◽  
Reproductive Function ◽  
Breeding Biology ◽  
Tree Frog ◽  
University Campus ◽  
Morphometric Measurements ◽  
Advertisement Calls ◽  
Males And Females

The breeding biology of tree frog, Polypedates teraiensis was studied during the breeding season at Mizoram University Campus. It was found that sound production by male during the breeding season was primarily a reproductive function and advertisement calls attract females to the breeding areas and announce other males that a given territory is occupied. The aim of this study was to provide the detailed information on the breeding behaviour and the advertisement calls of Polypedates teraiensis. The morphometric measurements of the amplecting pairs (males and females) for sexual dimorphism along with clutch sizes were also studied.

Spatial expression profiling reveals tissue-specific sexual dimorphism of the natriuretic peptide system in mice

2014 ◽  
Author(s):  
Samantha Mirczuk ◽  
Camille Robson ◽  
Benjamin Robinson ◽  
Andrew Lessey ◽  
Victoria Lipscomb ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Natriuretic Peptide ◽  
Expression Profiling ◽  
Tissue Specific ◽  
Spatial Expression ◽  
Peptide System ◽  
Natriuretic Peptide System

Sexual dimorphism in the mechanisms for insulin resistance

2019 ◽  
Author(s):  
Marcia Hiriart ◽  
Myrian Velasco ◽  
Marcia Hiriart
Keyword(s):  
Insulin Resistance ◽  
Sexual Dimorphism

Zophobas atratus (Fabricius, 1775) – new genus and species of darkling beetles (Coleoptera, Tenebrionidae) for the fauna of Ukraine

2018 ◽  
Vol 14 (1) ◽  
pp. 10-24
Author(s):  
V. N. Fursov ◽  
L. S. Cherney
Keyword(s):  
Life Cycle ◽  
Comparative Analysis ◽  
Sexual Dimorphism ◽  
Antennal Segment ◽  
Laboratory Culture ◽  
Important Species ◽  
Darkling Beetles ◽  
Zophobas Atratus ◽  
Sensory Zone ◽  
Coleoptera Tenebrionidae

Darkling beetle Zophobas atratus (Coleoptera, Tenebrionidae) is recorded here for the first time as a new species for the fauna of Ukraine. Detailed study on morphology of preimaginal stages and biology of this species recently introduced to Ukraine, is given here. Zophobas atratus is an important species being easily reared in laboratory cultures and widely distributed in North and South America, Europe, and Asia. Detailed descriptions of all life stages, including egg, young and older larvae, pupa and adult of Z. atratus are required for further taxonomical study of the genus Zophobas, which isn’t yet definitively established. New identification keys for adults and larvae of the genera of tribe Tenebrionini are presented here, based on a comparative analysis of the taxonomic characters of adults and larvae of Z. atratus and species from the genera Tenebrio and Neatus. Comparative analysis of morphology of larva of Z. atratus and larvae of the tribe Cteniopodini of close subfamily Alleculinae was conducted here. The subfamily Alleculinae previously had the rank of family Alleculidae, but our analysis confirmed the reliability of its current taxonomic position as subfamily. The study of morphology of larvae of 1st and 2nd instars of Z. atratus revealed that they are characterized by special taxonomic structures that are not characteristic for oldest instars of larvae of Z. atratus. These characters include absence of spines on caudal segment, presence of a set of 4 setae at posterior margin of tergites of prothorax, metathorax, and 1st to 8th abdominal segments, strongly convex 2nd antennal segment and sensory zone in the form of an open ring on its apex, and etc. Moreover, structure of antenna of larvae of Z. atratus is similar to that of oldest larvae of most species of darkling beetles of the fauna of Ukraine. The most distinctive features of Z. atratus are: sexual dimorphism in structure of clypeus of adults; filiform sclerotized antenna of larva with a continuous sensory zone at apex of 2nd segment, weakly developed 3rd segment; fusion of sclerotized pleurites of 1st–8th abdominal segments with their tergites; sexual dimorphism in structure of 9th abdominal segment of pupa, and presence of two hooks on apex of its appendages. The data of original study of features of life cycle of Z. atratus are given. The pictures and photos of details of morphology of egg, larvae, pupa and adult of Z. atratus are presented. It was recored that life cycle of Z. atratus from laying of egg to the emergence of adult continues from 169 up to 181 days. Adults lived maximum up to 206 days. Maturation of eggs in female after copulation continues 10-11 days. Stage of egg continues 7 days, larva – up to 151 days, including pre-pupal period from 6 to 22 days, pupa – from 8 to 21 days. Twelve larval stages of Z. atratus were recorded in laboratory culture.

Sexual Dimorphism among the Kathmandu University Students Assessed by Anthropometric Studies

2018 ◽  
Vol 9 (05) ◽  
pp. 20469-20472
Author(s):  
Shakya R ◽  
Bhattacharya SC ◽  
Shrestha R
Keyword(s):  
Young Adults ◽  
Sexual Dimorphism ◽  
Young Adult ◽  
University Students ◽  
Plastic Surgery ◽  
Age Group ◽  
Adult Age ◽  
Clinically Normal ◽  
Crime Detection ◽  
Males And Females

Objectives: To observe the sexual dimorphism among the young adult age group ranging from 18-21 years, of Kathmandu University students by measuring craniofacial circumference and canthal distances. Rationale of the study: These data could be useful for establishing the craniofacial standards and adds an implementation on plastic surgery, crime detection as well as in the industrial field. Method: 300 clinically normal students of Kathmandu University aged between 18-21 years were examined for the study. Fronto-occipital circumference, outer and inner canthal distances were measured. All the parameters were compared between males and females. Result: The cranial circumference as well as the inner and outer canthal distance in males was found to be significantly higher as compared to the females. Conclusion: The results concluded that sexual dimorphism remarkably exists in young adults of Kathmandu University students.

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