Sex-Specific Growth in Ospreys: The Role of Sexual Size Dimorphism

The Auk ◽  
1993 ◽  
Vol 110 (4) ◽  
pp. 900-910 ◽  
Author(s):  
David M. Bird
2020 ◽  
Vol 31 (3) ◽  
pp. 792-797
Author(s):  
Marcelo H Cassini

Abstract Sexual size dimorphism is biased toward males in most mammalian species. The most common explanation is precopulatory intramale sexual selection. Large males win fights and mate more frequently. In artiodactyls, previous tests of this hypothesis consisted of interspecific correlations of sexual dimorphism with group size as a surrogate for the intensity of sexual selection (Is). However, group size is not a proper measure of sexual selection for several reasons as is largely recognized in other mammalian taxa. I conducted an interspecific test on the role of sexual selection in the evolution of sexual dimorphism using the variance in genetic paternity as a proxy for the Is. I reviewed the literature and found 17 studies that allowed estimating Is= V/(W2), where V and W are the variance and mean number of offspring per male, respectively. A phylogenetic generalized least squares analysis indicated that dimorphism (Wm/Wf) showed a significant positive regression with the intensity of sexual selection but not group size (multiple r2= 0.40; F3,17= 12.78, P = 0.002). This result suggests that sexual selection may have played a role in the evolution of sexual size dimorphism in Artiodactyla. An alternative hypothesis based on natural selection is discussed.


Biology Open ◽  
2021 ◽  
Vol 10 (12) ◽  
Author(s):  
Fan Zhang ◽  
Xiaoqiong Chen ◽  
Chi Zeng ◽  
Lelei Wen ◽  
Yao Zhao ◽  
...  

ABSTRACT Sexual size dimorphism (SSD) is a notable phenomenon in terrestrial animals, and it is correlated with unusual morphological traits. To date, the underlying sex-specific growth strategies throughout the ontogenetic stage of spiders are poorly understood. Here, we comprehensively investigated how the growth trajectories and gonad development shaped SSD in the wolf spider Pardosa pseudoannulata (Araneae: Lycosidae). We also hypothesized the potential growth allometry among the carapace, abdomen, and gonads of spiders in both sexes. By measuring the size of the carapace and abdomen, investigating developmental duration and growth rate, describing the gonadal sections, and calculating the area of gonads at all instars from hatching to maturity, we demonstrated that SSD results from sex-specific growth strategies. Our results indicated that the growth and developmental differences between both sexes appeared at early life stages, and there was allometric growth in the carapace, abdomen, and gonads between males and females.


Oikos ◽  
2015 ◽  
Vol 125 (9) ◽  
pp. 1250-1260 ◽  
Author(s):  
Vicente García-Navas ◽  
Timothée Bonnet ◽  
Raúl Bonal ◽  
Erik Postma

Diabetes ◽  
1997 ◽  
Vol 46 (1) ◽  
pp. 138-142 ◽  
Author(s):  
R. Morishita ◽  
S. Nakamura ◽  
Y. Nakamura ◽  
M. Aoki ◽  
A. Moriguchi ◽  
...  

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