Fighting for harems: assessment strategies during male–male contests in the sexually dimorphic Wellington tree weta

2006 ◽  
Vol 72 (3) ◽  
pp. 727-736 ◽  
Author(s):  
Clint D. Kelly
Keyword(s):  
Sexually Dimorphic ◽  
Tree Weta ◽  
Assessment Strategies ◽  
Male Contests

Sexual dimorphism in the antennae of terrestrial isopods: a result of male contests or scramble competition?

2000 ◽  
Vol 78 (11) ◽  
pp. 1987-1993 ◽  
Author(s):  
F Lefebvre ◽  
M Limousin ◽  
Y Caubet
Keyword(s):  
Sexual Dimorphism ◽  
Negative Correlation ◽  
Morphological Analysis ◽  
Scramble Competition ◽  
Behavioral Analysis ◽  
Sexually Dimorphic ◽  
Selection Pressures ◽  
Terrestrial Isopods ◽  
Male Contests

In Oniscidea (terrestrial crustaceans), males are known to have longer antennae than females. This sexual dimorphism may result from a variety of selection pressures. However, some species are well known for their highly aggressive males, which use their antennae as weapons. We tested the hypothesis that longer antennae in males have been selected for by means of antennal contests. Morphological analysis of the antennae and behavioral analysis of male dyads were performed in parallel on 7 species. We demonstrate significant sexual dimorphism of the antennae in 6 of the 7 species, and various forms of male aggressiveness depending on the species. Our hypothesis was rejected because we found a negative correlation between the use of the antennae in contests and the magnitude of sexual dimorphism. Furthermore, some species are sexually dimorphic but the males never compete using their antennae. We propose and argue that scramble competition to be the first to find receptive females could explain why males have longer chemoreceptive antennae.

Behavioral roles of the sexually dimorphic structures in the male harvestman, Phalangium opilio (Opiliones, Phalangiidae)

2006 ◽  
Vol 84 (12) ◽  
pp. 1763-1774 ◽  
Author(s):  
Rodrigo H. Willemart ◽  
Jean-Pierre Farine ◽  
Alfredo V. Peretti ◽  
Pedro Gnaspini
Keyword(s):  
Electron Micrographs ◽  
Animal Species ◽  
Morphometric Study ◽  
Sexually Dimorphic ◽  
Scanning Electron Micrographs ◽  
Face To Face ◽  
Frequency Of Contact ◽  
Almost All ◽  
Male Contests ◽  
Scanning Electron

In various animal species, male sexual dimorphic characters may be used during intrasexual contests as ornaments to attract females, or to hold them before, during, or after copulation. In the well-known harvestman, Phalangium opilio L., 1758, the behavioral functions of these male sexually dimorphic structures have never been studied in detail. Therefore, in addition to a morphometric study, 21 male contests and 43 sexual interactions were analyzed. Our observations revealed that during contests, the male cheliceral horns form a surface by which the contestants use to push each other face-to-face while rapidly tapping their long pedipalps against the pedipalps of the opponent, occasionally twisting the opponent’s pedipalp. Scanning electron micrographs revealed contact mechanoreceptors on the pedipalp that would detect the intensity–frequency of contact with the contender’s pedipalp. Larger males won almost all contests, whereas the loser rapidly fled. During sexual interactions, the longer pedipalps of the male held legs IV of the female, whereas males with shorter pedipalps held the female by legs III. No contact with the male pedipalps and chelicerae by the females was visible before, during, or after copulation. Soon after copulating, males typically bent over the female, positioning their cheliceral horns against the females’s dorsum. Consequently, our data show that the cheliceral horns and the longer pedipalps of the male seem to play an important role, during both intersexual and intrasexual encountering.

Androgen-induced plasticity at a “vocal” neuromuscular synapse

1994 ◽  
Vol 52 ◽  
pp. 32-33
Author(s):  
Darcy B. Kelley ◽  
Martha L. Tobias ◽  
Mark Ellisman
Keyword(s):  
Xenopus Laevis ◽  
Motor Neurons ◽  
Sexual Differentiation ◽  
Molecular Basis ◽  
Neuromuscular Synapse ◽  
Sexually Dimorphic ◽  
Intracellular Protein ◽  
Developmental Program ◽  
Androgen Action ◽  
Clawed Frog

Brain and muscle are sexually differentiated tissues in which masculinization is controlled by the secretion of androgens from the testes. Sensitivity to androgen is conferred by the expression of an intracellular protein, the androgen receptor. A central problem of sexual differentiation is thus to understand the cellular and molecular basis of androgen action. We do not understand how hormone occupancy of a receptor translates into an alteration in the developmental program of the target cell. Our studies on sexual differentiation of brain and muscle in Xenopus laevis are designed to explore the molecular basis of androgen induced sexual differentiation by examining how this hormone controls the masculinization of brain and muscle targets.Our approach to this problem has focused on a highly androgen sensitive, sexually dimorphic neuromuscular system: laryngeal muscles and motor neurons of the clawed frog, Xenopus laevis. We have been studying sex differences at a synapse, the laryngeal neuromuscular junction, which mediates sexually dimorphic vocal behavior in Xenopus laevis frogs.

The Relationship of Digit Ratio (2D:4D) and Gender-Role Orientation in Four National Samples

2007 ◽  
Vol 28 (2) ◽  
pp. 78-87 ◽  
Author(s):  
Stefan J. Troche ◽  
Nina Weber ◽  
Karina Hennigs ◽  
Carl-René Andresen ◽  
Thomas H. Rammsayer
Keyword(s):  
Gender Role ◽  
Sex Role ◽  
Role Orientation ◽  
Sexually Dimorphic ◽  
Gender Role Orientation ◽  
Left Hand ◽  
Fourth Finger ◽  
And Gender ◽  
Relationship Of ◽  
The Relationship

Abstract. The ratio of second to fourth finger length (2D:4D ratio) is sexually dimorphic with women having higher 2D:4D ratio than men. Recent studies on the relationship between 2D:4D ratio and gender-role orientation yielded rather inconsistent results. The present study examines the moderating influence of nationality on the relationship between 2D:4D ratio and gender-role orientation, as assessed with the Bem Sex-Role Inventory, as a possible explanation for these inconsistencies. Participants were 176 female and 171 male university students from Germany, Italy, Spain, and Sweden ranging in age from 19 to 32 years. Left-hand 2D:4D ratio was significantly lower in men than in women across all nationalities. Right-hand 2D:4D ratio differed only between Swedish males and females indicating that nationality might effectively moderate the sexual dimorphism of 2D:4D ratio. In none of the examined nationalities was a reliable relationship between 2D:4D ratio and gender-role orientation obtained. Thus, the assumption of nationality-related between-population differences does not seem to account for the inconsistent results on the relationship between 2D:4D ratio and gender-role orientation.

All in the Family: An Overview of Assessment Strategies

1989 ◽  
Vol 34 (11) ◽  
pp. 993-994
Author(s):  
Donald H. Baucom
Keyword(s):  
The Family ◽  
Assessment Strategies

Chemogenetic inhibition of dopaminergic projections to the nucleus accumbens has sexually dimorphic effects in the rat gambling task.

2020 ◽  
Vol 134 (4) ◽  
pp. 309-322 ◽  
Author(s):  
Tristan J. Hynes ◽  
Jacqueline-Marie M. Ferland ◽  
Tanya L. Feng ◽  
Wendy K. Adams ◽  
Mason M. Silveira ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Sexually Dimorphic ◽  
Gambling Task

Evidence-based assessment strategies for working with ethnic minority youth.

2017 ◽  
Vol 5 (1) ◽  
pp. 108-120 ◽  
Author(s):  
Jessica M. Valenzuela ◽  
Elizabeth R. Pulgaron ◽  
Katherine S. Salamon ◽  
Anna Maria Patiño-Fernandez
Keyword(s):  
Ethnic Minority ◽  
Minority Youth ◽  
Evidence Based ◽  
Ethnic Minority Youth ◽  
Assessment Strategies
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