scholarly journals Higher reproductive success of small males and greater recruitment of large females may explain strong reversed sexual dimorphism (RSD) in the northern goshawk

Oecologia ◽  
2014 ◽  
Vol 177 (2) ◽  
pp. 379-387 ◽  
Author(s):  
L. Pérez-Camacho ◽  
G. García-Salgado ◽  
S. Rebollo ◽  
S. Martínez-Hesterkamp ◽  
J. M. Fernández-Pereira
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Northern Goshawk ◽  
Reversed Sexual Dimorphism

scholarly journals Safe sex: male–female coalitions and pre-copulatory mate-guarding in a fiddler crab

2009 ◽  
Vol 6 (2) ◽  
pp. 180-182 ◽  
Author(s):  
Richard N. C. Milner ◽  
Michael D. Jennions ◽  
Patricia R. Y. Backwell
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Observational Data ◽  
Fiddler Crab ◽  
Lower Boundary ◽  
Mate Guarding ◽  
Maintenance Costs ◽  
Boundary Maintenance ◽  
Uca Annulipes ◽  
Males And Females

In fiddler crabs both males and females defend territories that are essential for survival. Given pronounced sexual dimorphism in weaponry, how do weaponless females defend their territory from well-armed males? Using observational data and two simple experiments, we test whether male Uca annulipes protect their female neighbours from conspecific intruders. We show that males defend their female neighbours against male but not female intruders. We also show that females sometimes mate with their immediate neighbours. Male defence of female neighbours appears to represent both pre-copulatory mate-guarding and a territorial coalition. Males who ensure that their neighbour remains female could benefit through increased opportunity for future reproductive success and lower boundary maintenance costs.

Reversed sexual dimorphism in the beak of a finch

Ibis ◽  
2003 ◽  
Vol 145 (2) ◽  
pp. 341-343 ◽  
Author(s):  
Peter R. Grant ◽  
B. Rosemary Grant
Keyword(s):  
Sexual Dimorphism ◽  
Reversed Sexual Dimorphism

Breeding habitat preferences and reproductive success of Northern Goshawk (Accipiter gentilis) in exotic Eucalyptus plantations in southwestern Europe

2018 ◽  
Vol 409 ◽  
pp. 817-825 ◽  
Author(s):  
G. García-Salgado ◽  
S. Rebollo ◽  
L. Pérez-Camacho ◽  
S. Martínez-Hesterkamp ◽  
E. De la Montaña ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Habitat Preferences ◽  
Breeding Habitat ◽  
Accipiter Gentilis ◽  
Northern Goshawk ◽  
Eucalyptus Plantations

scholarly journals Reversed sexual dimorphism and altered prey base: the effect on sooty owl (Tyto tenebricosa tenebricosa) diet

2011 ◽  
Vol 59 (5) ◽  
pp. 302 ◽  
Author(s):  
Rohan J. Bilney ◽  
John G. White ◽  
Raylene Cooke
Keyword(s):  
Sexual Dimorphism ◽  
Small Mammals ◽  
Prey Availability ◽  
Mammalian Species ◽  
Control Programs ◽  
European Settlement ◽  
Mammal Conservation ◽  
Reversed Sexual Dimorphism ◽  
Conservation Concern ◽  
And Function

The ecology and function of many Australian predators has likely been disrupted following major changes in prey base due to declines in distribution and abundance of small mammals following European settlement. This study investigated various aspects of the dietary ecology of sooty owls (Tyto tenebricosa tenebricosa), including sexual variation as they potentially exhibit the greatest degree of reversed sexual dimorphism of any owl species worldwide. Sooty owls are highly opportunistic predators of non-volant small mammals, consuming most species known to exist in the region, so their diet fluctuates seasonally and spatially due to varying prey availability, and is particularly influenced by the breeding cycles of prey. Significant intersexual dietary differences existed with female sooty owls predominantly consuming much larger prey items than males, with dietary overlap at 0.62. The current reliance on relatively few native mammalian species is of conservation concern, especially when mammal declines are unlikely to have ceased as many threatening processes still persist in the landscape. Sooty owl conservation appears inextricably linked with small mammal conservation. Conservation efforts should be focussed towards improving prey densities and prey habitat, primarily by implementing control programs for feral predators and preventing the loss of hollow-bearing trees throughout the landscape.

scholarly journals A new miniature Pristella (Actinopterygii: Characiformes: Characidae) with reversed sexual dimorphism from the rio Tocantins and rio São Francisco basins, Brazil

2021 ◽  
pp. 339-348
Author(s):  
F.C.T. Lima ◽  
R.A. Caires ◽  
C.C. Conde-Saldaña ◽  
J.M. Mirande ◽  
F.R. Carvalho
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Sexual Dimorphism ◽  
Color Pattern ◽  
Bony Fishes ◽  
Reversed Sexual Dimorphism ◽  
A New Species

A new species of the genus Pristella Eigenmann, 1908 (Pristella crinogi sp. nov.) is described from the middle rio Tocantins and middle rio São Francisco basins, Brazil. The new species can be diagnosed from its two congeners, Pristella ariporo Conde-Saldaña, Albornoz-Garzón, García-Melo, Villa-Navarro, Mirande, and Lima, 2019 and Pristella maxillaris (Ulrey, 1894), by a combination of color pattern and teeth morphology characters. A phylogenetic analysis of the genus recovered P. crinogi as the sister taxa of P. ariporo. Pristella crinogi, along with P. ariporo, are the first characiform fishes, and one of the first bony fishes, to be reported as presenting a reversed sexual dimorphism, with females presenting a more developed color pattern than males. Comments on the miniaturization of the species, as well as remarks on the biogeography of the genus Pristella, are presented.

scholarly journals A Comparative Study of the Canine Tooth as a Tool in Gender Determination in Nigerian Population

2019 ◽  
Vol 26 (2) ◽  
Author(s):  
Peter O Otuaga ◽  
Lilian Ebite Chris-Ozoko ◽  
Oghenetega Lynda Sakpoba ◽  
John Chukwuma Oyem
Keyword(s):  
Sexual Dimorphism ◽  
Sex Determination ◽  
Canine Tooth ◽  
Maxillary Canine ◽  
Male And Female ◽  
Study Results ◽  
Significant Difference ◽  
Nigerian Population ◽  
Reversed Sexual Dimorphism ◽  
Dental Evidence

Dental evidence has been demonstrated as a major forensic tool for the identification of individuals and sex determination. The objective of the research was to determine sex in Delta Ibo ethnic group of Nigeria using the mandibular and maxillary canine teeth. Materials and methods. The study comprised 201 (100 males and 101 females) subjects of Delta Ibo ethnicity at the age of 17 – 25 years. The mesiodistal crown width and intercanine distance of both the maxillary and mandibular canines were measured intraorally using a pair of dividers and a ruler. Unpaired T-test at a probability value of p<0.05 was used to ascertain the mean significant differences between the male and female canine indices.   Results. Study results showed a statistically significant difference between male and female mandibular and maxillary canine mesiodistal width. This implied a sexual and reversed sexual dimorphism in the studied population.        Conclusions. The study confirmed that the canines of Delta Ibos exhibit sexual dimorphism like other populations and the maxillary canine indices give the most accurate prediction in sex determination.

Sexual dimorphism in the claws of the European terrapin (Emys orbicularis): potential implications for the reproductive fitness of the species.

2019 ◽  
Author(s):  
Gonzalo Alarcos ◽  
Jaime Madrigal-González ◽  
Miguel Lizana ◽  
Fabio Flechoso
Keyword(s):  
Sexual Selection ◽  
Comparative Analysis ◽  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Sexual Maturity ◽  
Reproductive Fitness ◽  
Emys Orbicularis ◽  
Future Studies ◽  
Different Populations ◽  
Males And Females

There are many biometric differences between the males and females of the European pond turtle (Emys orbicularis) as regards their size, colouring, the shape of the plastron, tail, etc. The males use their claws to grasp the female during copulation and hence sexual selection should favour the males that have larger claws, which allow them to grasp the female better. Here, we address this type of sexual dimorphism in a comparative analysis of indices obtained from claw length, the length of the carapace and the locality where individuals were sampled. The results show that the curvature of the claws differs between the two sexes, being longer in males and increasing with age, size, and hence, the state of sexual maturity, than in females. Greater claw length could confer advantages for males when grasping the carapace of females, and hence, improve their reproductive fitness. Importance in the reproductive success that might have this feature in males could originate future studies that will relate the shape, thickness, length and other measures of the claws in males with their reproductive success in different populations, genetic variety, and most importantly, viability of populations. 

Effects of hypophysectomy and growth hormone infusion on rat hepatic carbonic anhydrases

1986 ◽  
Vol 110 (1) ◽  
pp. 123-126 ◽  
Author(s):  
S. Jeffery ◽  
C. A. Wilson ◽  
A. Mode ◽  
J.-Å. Gustafsson ◽  
N. D. Carter
Keyword(s):  
Growth Hormone ◽  
Sexual Dimorphism ◽  
Carbonic Anhydrase ◽  
Sexual Differentiation ◽  
Isozyme Pattern ◽  
Male Rats ◽  
Carbonic Anhydrases ◽  
Reversed Sexual Dimorphism ◽  
Normal Males ◽  
Soluble Carbonic Anhydrase

ABSTRACT Rat liver exhibits a reversed sexual dimorphism of its two endogenous soluble carbonic anhydrase (CA) isozymes, CA II and CA III. Normal males have hepatic CA III concentrations ten–twenty times those in the female, while female liver contains two–three times more CA II than the male. Hypophysectomy abolishes this sexual differentiation, having no effect on male liver but producing isozyme concentrations in the female liver similar to those in the male. Infusion of a continuous level of GH into male rats induces a female-like isozyme pattern for both CA II and CA III. J. Endocr. (1986) 110, 123–126

Sign in / Sign up

Export Citation Format

Share Document