Sexual dimorphism and mating systems: jumping to conclusions

1986 ◽  
Vol 1 (3) ◽  
pp. 215-219 ◽  
Author(s):  
T. E. Rowell ◽  
J. Chism
Keyword(s):  
Sexual Dimorphism ◽  
Mating Systems ◽  
Jumping To Conclusions

Interspecific variation in sexual dimorphism in brain size in Nearctic ground squirrels (Spermophilus spp.)

2001 ◽  
Vol 79 (5) ◽  
pp. 759-765 ◽  
Author(s):  
Andrew N Iwaniuk
Keyword(s):  
Sex Differences ◽  
Body Size ◽  
Sexual Dimorphism ◽  
Ground Squirrel ◽  
Mating Systems ◽  
Resource Competition ◽  
Brain Size ◽  
Ground Squirrels ◽  
Detailed Knowledge ◽  
Size Dimorphism

A possible relationship between sexual dimorphism in brain size and mating system was investigated in five ground squirrel species: Spermophilus lateralis, S. tridecemlineatus, S. richardsonii, S. columbianus, and S. parryii. Relative brain size was measured by determining the endocranial volume of 247 ground squirrel skulls and regressing these values against two measurements of body size: mass and length. Analyses of covariation in the brain size / body size relationship within the five species revealed that sexual brain-size dimorphism occurs in three of the five species: S. lateralis, S. richardsonii, and S. tridecemlineatus. Application of a reduced major axis regression model indicated, however, that only S. lateralis and S. richardsonii exhibit significant sexual brain-size dimorphism. These findings suggest that the degree of sexual brain-size dimorphism is not directly correlated with variation in mating systems. Spatial abilities may play a role in the evolution of sexual brain-size dimorphism in ground squirrels, but the spatial requirements of mating systems appear to be insufficient. The possibility of sex differences in cognition, resource competition, and other variables as contributory factors to the evolution of sexual brain-size dimorphism is offered, but detailed knowledge of sex differences in the behaviour of ground squirrels is required to provide a definitive answer.

Sexual Dimorphism and Mating Systems in Voles

1993 ◽  
Vol 74 (1) ◽  
pp. 230-233 ◽  
Author(s):  
R. S. Ostfeld ◽  
E. J. Heske
Keyword(s):  
Sexual Dimorphism ◽  
Mating Systems

The significance of sexual dimorphism in the mating system of two species of tephritid flies (Aciurina trixa and Valentibulla dodsoni) (Diptera: Tephritidae)

1987 ◽  
Vol 65 (1) ◽  
pp. 194-198 ◽  
Author(s):  
Gary Dodson
Keyword(s):  
Sexual Dimorphism ◽  
Mating System ◽  
Mating Systems ◽  
Natural Populations ◽  
Adaptive Significance ◽  
Male Behavior ◽  
Field Cage ◽  
Copulatory Success

The mating systems of Aciurina trixa and Valentibulla dodsoni (Diptera: Tephritidae) were observed in natural populations and field cage studies. Measurements of field-collected individuals of both species revealed that females were larger than males based on five size categories, but males had larger forefemora. Male behavior suggested that selection might favor increased foreleg size, due to a resulting enhancement of male ability to seize females prior to mounting. Male forefemur size was found to be a predictor of copulatory success in both species. Hypotheses concerning the adaptive significance of this sexual dimorphism are discussed.

MATING SYSTEMS, SPERM COMPETITION, AND THE EVOLUTION OF SEXUAL DIMORPHISM IN BIRDS

Evolution ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 161 ◽  
Author(s):  
Peter O. Dunn ◽  
Linda A. Whittingham ◽  
Trevor E. Pitcher
Keyword(s):  
Sexual Dimorphism ◽  
Sperm Competition ◽  
Mating Systems

scholarly journals Mating Systems and Sexual Dimorphism in Mass in Microtines

1993 ◽  
Vol 74 (1) ◽  
pp. 224-229 ◽  
Author(s):  
R. Boonstra ◽  
B. S. Gilbert ◽  
C. J. Krebs
Keyword(s):  
Sexual Dimorphism ◽  
Mating Systems
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