scholarly journals Rich but not poor conditions determine sex‐specific differences in growth rate of juvenile dioecious plants

2021 ◽  
Author(s):  
Kinga Nowak ◽  
Marian J. Giertych ◽  
Emilia Pers-Kamczyc ◽  
Peter A. Thomas ◽  
Grzegorz Iszkuło
Keyword(s):  
Sexual Dimorphism ◽  
Life Histories ◽  
Soil Conditions ◽  
Taxus Baccata ◽  
Root Mass ◽  
Compensatory Mechanisms ◽  
Dioecious Species ◽  
Dioecious Plants ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

AbstractCauses of secondary sexual dimorphism (SSD) in dioecious plants are very poorly understood, especially in woody plants. SSD is shown mainly in mature plants, but little is known about whether secondary sexual dimorphism can occur in juveniles. It is also assumed that stress conditions intensify differences between the sexes due to the uneven reproductive effort. Therefore, the following research hypotheses were tested: (1) secondary sexual dimorphism will be visible in juveniles; (2) unfavourable soil conditions are the cause of more pronounced differences between the sexes. Rooted shoots of the common yew (Taxus baccata L.) and common juniper (Juniperus communis L.), previously harvested from parental individuals of known sex were used in the study. During two growing seasons vegetation periods and four times a year, comprehensive morphological features of whole plants were measured. Some SSD traits were visible in the analysed juveniles. Contrary to expectations, differences were more pronounced in the fertilized treatment. Both species reacted to fertilization in different ways. Female yew had a clearly higher total plant mass, root mass, and mean root area when fertilized, whereas male juniper had a higher root mass when fertilized. Differences between the sexes independent of the fertilization treatment were seen, which can be interpreted as sexual adaptations to a continued reproduction. Female yews and male junipers made better use of fertile habitats. Our study showed that SSD may be innate, and sexual compensatory mechanisms could generate uneven growth and development of both sexes. Because the SSD pattern was rather different in both species, it was confirmed that SSD is connected with the specific life histories of specific species rather than a universal strategy of dioecious species.

Do secondary sexual dimorphism and female intolerance to drought influence the sex ratio and extinction risk of Taxus baccata?

Plant Ecology ◽  
2008 ◽  
Vol 200 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Grzegorz Iszkuło ◽  
Anna K. Jasińska ◽  
Marian J. Giertych ◽  
Adam Boratyński
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratio ◽  
Extinction Risk ◽  
Taxus Baccata ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

scholarly journals Extreme secondary sexual dimorphism in the genus Florarctus (Heterotardigrada: Halechiniscidae)

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Piotr Gąsiorek ◽  
David Møbjerg Kristensen ◽  
Reinhardt Møbjerg Kristensen
Keyword(s):  
Sexual Dimorphism ◽  
Pacific Ocean ◽  
Barrier Reef ◽  
Queensland Museum ◽  
The Pacific ◽  
Secondary Sexual Dimorphism ◽  
The Pacific Ocean ◽  
A New Species ◽  
Lines Of Evidence ◽  
Secondary Sexual

AbstractSecondary sexual dimorphism in florarctin tardigrades is a well-known phenomenon. Males are usually smaller than females, and primary clavae are relatively longer in the former. A new species Florarctus bellahelenae, collected from subtidal coralline sand just behind the reef fringe of Long Island, Chesterfield Reefs (Pacific Ocean), exhibits extreme secondary dimorphism. Males have developed primary clavae that are much thicker and three times longer than those present in females. Furthermore, the male primary clavae have an accordion-like outer structure, whereas primary clavae are smooth in females. Other species of Florarctus Delamare-Deboutteville & Renaud-Mornant, 1965 inhabiting the Pacific Ocean were investigated. Males are typically smaller than females, but males of Florarctus heimi Delamare-Deboutteville & Renaud-Mornant, 1965 and females of Florarctus cervinus Renaud-Mornant, 1987 have never been recorded. The Renaud-Mornant collection was re-examined, and type series were analysed. Florarctus heimi and F. cervinus were always found together in the coralline sand of Heron Island (Great Barrier Reef). The animals were kept alive and surveyed in the laboratory of the Queensland Museum. All studied individuals of the larger F. heimi (up to ca. 400 μm) were females, and all adults of the smaller F. cervinus (about 170 μm) were males. Males of F. cervinus were observed mating with females of F. heimi. Following those morphological and behavioural lines of evidence, we propose that F. cervinus is a junior synonym of F. heimi. Based on the discovery of dimorphism in F. bellahelenae sp. nov. and the strong sex-related morphological disparities in F. heimi, we suggest that extreme secondary dimorphism may be present in other florarctin arthrotardigrades.

Life-history studies–a new approach to the taxonomy of ligulate species of Desmarestia (Phaeophyceae) from the Pacific coast of Canada

1986 ◽  
Vol 64 (10) ◽  
pp. 2192-2196 ◽  
Author(s):  
Akira F. Peters ◽  
Dieter G. Müller
Keyword(s):  
Life History ◽  
Sexual Dimorphism ◽  
North America ◽  
Life Histories ◽  
Pacific Coast ◽  
Culture Conditions ◽  
Growth Forms ◽  
Dioecious Species ◽  
New Approach ◽  
The Pacific

Life histories of two ligulate forms of Desmarestia with different phylloid width from one site on the Canadian Pacific coast were studied in culture. Meiospores from a form with narrow phylloids germinated into monoecious gametophytes. Meiospores from a form with broad phylloids developed into dioecious gametophytes, showing sexual dimorphism characteristic for dioecious species of Desmarestia. The two growth forms also differed in culture conditions required for gametogenesis. We conclude that at least two different species of ligulate Desmarestia occur on the Pacific coast of North America.

scholarly journals Postembryonic development, paedomorphosis, secondary sexual dimorphism and population structure of a newFlorarctusspecies (Tardigrada, Heterotardigrada)

2016 ◽  
Vol 178 (4) ◽  
pp. 871-877 ◽  
Author(s):  
Jesper Guldberg Hansen ◽  
Reinhardt Møbjerg Kristensen ◽  
Aslak Jørgensen ◽  
Gianluca Accogli ◽  
Rossanna D'Addabbo ◽  
...  
Keyword(s):  
Population Structure ◽  
Sexual Dimorphism ◽  
Postembryonic Development ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

scholarly journals Identificación individual de tepezcuincle (Cuniculus paca) mediante el uso de huellas.

2009 ◽  
Vol 13 (1) ◽  
pp. 34 ◽  
Author(s):  
Rusby Guadalupe Contreras–Díaz ◽  
Antonio Santos–Moreno ◽  
Ana María Alfaro ◽  
Martín Pérez–Lustre
Keyword(s):  
Sexual Dimorphism ◽  
Principal Component ◽  
Wilcoxon Test ◽  
Individual Identification ◽  
Secondary Sexual Dimorphism ◽  
Para Determinar ◽  
Del Rio ◽  
San Martín ◽  
Plaster Casts ◽  
Secondary Sexual

Resumen: El presente estudio tuvo como objetivo diseñar un método para la identificación entre individuos de tepezcuintle (Cuniculus paca), mediante las características de sus huellas, así como probar su eficiencia en campo.  Se obtuvieron moldes de yeso de las huellas de 11 individuos en cautiverio a los cuales se les tomaron diferentes medidas (seis lineales y un ángulo).  Para determinar si existe dimorfismo sexual secundario en cada una de las variables, se aplicó la prueba no paramétrica de Wilcoxon.  Se realizó una estandarización de los datos para así emplear un Análisis de Componentes Principales (ACP) con matriz de variaza-covarianza.  Para llevar a cabo el método en campo se obtuvieron moldes de huellas en un transecto (1 km) establecido en los márgenes del río Soyolapan, en San Martín Soyolapan, Oaxaca, durante dos periodos de colecta de cinco días cada uno en los meses de diciembre de 2006 y enero de 2007.  No encontramos diferencias estadísticamente significativas entre las huellas de machos y hembras, por lo que se concluye que no hay dimorfismo sexual secundario en las huellas de tepezcuintle.  Mediante el ACP es posible llegar a identificar el 61 % de los individuos, utilizando los dos primeros Componentes Principales (CP1 y CP2).  Al aplicar el método en San Martín Soyolapan se estimó una abundancia de cinco individuos.Palabras clave: Identificación individual, tepezcuintle, huellas, Oaxaca.Abstract:The present study had as an objective to design a method to identify individual pacas (Cuniculus paca) using their track characteristics and to apply it in the field. Plaster casts were obtained from the tracks of captive individual pacas, and six linear measures and one angle were taken. To determine if secondary sexual dimorphism exists, a Wilcoxon test was applied to each variable.  A Principal Component Analysis (PCA) was applied over a covariance matrix of standardized data.  For the application of the method in the field, plaster casts were obtained in a 1 km transect established at the edge of the Soyolapan river, in San Martín Soyolapan, Santiago Comaltepec, Oaxaca, during two periods of five days each, in December 2006 and January 2007.  We found no differences between male and female tracks, so we concluded that secondary sexual dimorphism in paca tracks does not exist.  By means of PCA it was possible to identify 61 % of the individuals analyzed.  When applying this method an abundance of five individuals was estimated for the San Martín Soyolapan site.Key words: Individual identification, paca, tracks, Oaxaca. 

scholarly journals Two new species of Characidium Reinhardt (Characiformes: Crenuchidae) from northeastern Brazilian coastal drainages

2015 ◽  
Vol 13 (3) ◽  
pp. 487-498 ◽  
Author(s):  
Angela M. Zanata ◽  
Priscila Camelier
Keyword(s):  
New Species ◽  
Sexual Dimorphism ◽  
Posterior Margin ◽  
The Other ◽  
Caudal Fin ◽  
Two New Species ◽  
Black Blotch ◽  
Secondary Sexual Dimorphism ◽  
Secondary Sexual

Two new species of Characidium , onefrom the rio Pardo basin, and anotherfrom the rio Paraguaçu basin, Bahia, Brazil, are described. The first new speciesis distinguished from its congeners by having conspicuous black vertical traces on body, formed by the concentration of melanophores along posterior margin of scales. The species further differs from most congeners by the presence of a conspicuous 3-shaped black blotch on the caudal fin and isthmus not covered by scales. The other new species is distinguished from congeners by having irregular dark blotches on dorsum alternating elongation to one or the other side of body, usually not connected to lateral blotches. The species can be further characterized by the absence of conspicuous blotches or bars on fins and the presence of secondary sexual dimorphism, such as pelvic fins of mature males longer than in females and with bony hooks.

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