Secondary sexual characters signal fighting ability and determine social rank in Alpine ibex (Capra ibex)

2010 ◽  
Vol 64 (8) ◽  
pp. 1299-1307 ◽  
Author(s):  
Patrick Bergeron ◽  
Stefano Grignolio ◽  
Marco Apollonio ◽  
Bill Shipley ◽  
Marco Festa-Bianchet
2007 ◽  
Vol 16 (9) ◽  
pp. 1969-1980 ◽  
Author(s):  
ACHAZ VON HARDENBERG ◽  
BRUNO BASSANO ◽  
MARCO FESTA-BIANCHET ◽  
GORDON LUIKART ◽  
PAOLO LANFRANCHI ◽  
...  

Author(s):  
Christian Simon Willisch ◽  
Peter Neuhaus

AbstractTrade-offs between reproductive effort and subsequent growth in males are not well explored, despite their relevance in questions of individual energy allocation. Regarding the growth of sexual secondary characters in polygynous breeding male mammals, indeed, no conclusive studies exist. We investigated in male Alpine ibex (Capra ibex) the relationship between their behavioral reproductive effort, current horn size, and subsequent horn growth. While controlling for age, no evidence was found for male behavioral reproductive effort during the rut being affected by their horn size. On the other hand, reproductive effort significantly decreased age-specific horn growth during the following summer. Our study provides evidence that growth of secondary sexual characters is traded against behavioral investments in reproduction in a male mammal. It bears important implications for the understanding of energy allocation between various life-history components and the evolutionary ecology of secondary sexual characters.


2016 ◽  
Vol 26 (3) ◽  
pp. 397-402 ◽  
Author(s):  
Toshiaki Yamamoto ◽  
Noritaka Hirohashi ◽  
Eiji Fujiwara ◽  
Tatsuya Suzuki ◽  
Hatsuna Maruta ◽  
...  

2010 ◽  
Vol 60 (2) ◽  
pp. 195-208 ◽  
Author(s):  
Laura Susana López Greco ◽  
Fernanda Jimena Vazquez

AbstractThe differentiation of the male reproductive system, the copulatory structures, "red patch" and onset of sexual maturity were studied in Cherax quadricarinatus. For this characterization 353 males were observed, dissected and processed for histological analysis. Three developmental stages were identified. At stage I the testes are two parallel cords with a few lobes or acinii, connected medially by a short thin bridge (X-shape) and the vasa deferentia are straight transparent cords. In the second stage, more lobulated testes present an H-shape and the vas deferens begins to differentiate into three distinct regions: proximal, medial and distal. In the last stage testes are two parallel cords tending to fuse along their entire length and become a single structure. From this stage, the development of the "red patch" occurs and spermatophore formation is observed in the vas deferens giving it white colour. These primary and secondary sexual characters could indicate the onset of sexual maturity. The morphology of the copulatory structure is lobular at stage I and it differentiates into an elongated structure during stage II. This study shows that in C. quadricarinatus the differentiation of primary and secondary sexual characters of males starts simultaneously and very early in development (0.09-0.10g achieved nearly 1 month old) and that acquisition of sexual maturity is also an early event (6g achieved nearly 3 month old). The compared features within Astacidea and Decapoda and the possible applications in the analysis of phylogenetic relationships between different taxa are discussed.


2020 ◽  
Vol 418 ◽  
pp. 1-8
Author(s):  
I. Ya. Grichanov ◽  

A new species Sybistroma genriki sp. n. from the Yunnan province of China is described. It belongs to S. incisa group of species, differing from other species in mostly yellow antenna with arista-like stylus much longer than postpedicel; postpedicel elongated, much longer than wide, acute apically; stylus apical, with dark and white apical swelling; lower postocular setae white; legs mostly yellow except mostly black mid and hind coxae and brown-black distal spot on hind femur. A key to 11 species from Sichuan and Yunnan is provided, based mainly on male secondary sexual characters. The known distribution of the dolichopodine genus Sybistroma Meigen, 1824, is briefly discussed.


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