Mechanisms Influencing Countergradient Variation in Prairie Lizards, Sceloporus consobrinus

2019 ◽  
Vol 53 (3) ◽  
pp. 196
Author(s):  
Angela Lenard ◽  
Matthew E. Gifford
Keyword(s):  
Countergradient Variation

scholarly journals Evidence of Countergradient Variation in Growth of Spotted Gars from Core and Peripheral Populations

2015 ◽  
Vol 144 (4) ◽  
pp. 837-850 ◽  
Author(s):  
Solomon R. David ◽  
Richard S. Kik ◽  
James S. Diana ◽  
Edward S. Rutherford ◽  
Michael J. Wiley
Keyword(s):  
Peripheral Populations ◽  
Countergradient Variation

Countergradient variation in growth and food conversion efficiency of juvenile turbot

2000 ◽  
Vol 57 (5) ◽  
pp. 1213-1226 ◽  
Author(s):  
A. K. Imsland ◽  
A. Foss ◽  
G. Nevdal ◽  
T. Cross ◽  
S. W. Bonga ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Food Conversion ◽  
Countergradient Variation ◽  
Juvenile Turbot ◽  
Food Conversion Efficiency

scholarly journals COUNTERGRADIENT VARIATION IN THE SEXUAL COLORATION OF GUPPIES (POECILIA RETICULATA): DROSOPTERIN SYNTHESIS BALANCES CAROTENOID AVAILABILITY

Evolution ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 175-188 ◽  
Author(s):  
Gregory F. Grether ◽  
Molly E. Cummings ◽  
Jocelyn Hudon
Keyword(s):  
Poecilia Reticulata ◽  
Countergradient Variation ◽  
Sexual Coloration

Inheritance of geographic variation in body size, and countergradient variation in growth rates, in the southern brown bandicoot Isoodon obesulus.

2000 ◽  
Vol 22 (1) ◽  
pp. 9 ◽  
Author(s):  
ML Hale
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Body Size ◽  
Geographic Variation ◽  
Growth Rates ◽  
Habitat Type ◽  
Adaptive Divergence ◽  
Common Environment ◽  
Countergradient Variation ◽  
Large Animals

The inheritance of geographic variation in body size in the southern brown bandicoot (Isoodon obesulus) was investigated through a common-environment crossbreeding experiment. The geographic variation in body size is related to habitat type, suggesting that it may be adaptive. Adults from two locations in Western Australia, Perth (large animals) and Albany (small animals), were collected and offspring from both hybrid and non-hybrid matings were reared under controlled conditions. All four variables examined (head length, pes length, ear length and body weight) were found to possess a large genetic component, supporting the interpretation that the geographic variation in size is adaptive. The three length variables initially showed additive genetic variation, although the variation in body weight displayed dominance. Genetically controlled differences in growth rate were also detected, with the smaller animals, found in the relatively poorer environment, possessing the faster intrinsic growth rate. Thus, not only does there appear to be adaptive divergence in initial body size, but the countergradient variation in growth rates provides additional evidence for adaptive divergence in this species.

scholarly journals Female mate preference explains countergradient variation in the sexual coloration of guppies ( Poecilia reticulata )

2011 ◽  
Vol 279 (1734) ◽  
pp. 1684-1690 ◽  
Author(s):  
Kerry A. Deere ◽  
Gregory F. Grether ◽  
Aida Sun ◽  
Janet S. Sinsheimer
Keyword(s):  
Geographical Variation ◽  
Poecilia Reticulata ◽  
Direct Evidence ◽  
Carotenoid Content ◽  
Pigment Ratio ◽  
Male Attractiveness ◽  
Countergradient Variation ◽  
Sexual Coloration ◽  
Two Populations ◽  
Orange Spot

We tested the hypothesis that mate choice is responsible for countergradient variation in the sexual coloration of Trinidadian guppies ( Poecilia reticulata ). The nature of the countergradient pattern is that geographical variation in the carotenoid content of the orange spots of males is counterbalanced by genetic variation in drosopterin production, resulting in a relatively uniform pigment ratio. A female hue preference could produce this pattern, because hue is the axis of colour variation most directly affected by the pigment ratio. To test this hypothesis, we crossed two populations differing in drosopterin production and produced an F 2 generation with variable drosopterin levels. When the carotenoid content of the orange spots was held constant, female guppies preferred males with intermediate drosopterin levels. This shows that females do not simply prefer males with greater orange spot pigment content; instead, the ratio of the pigments also affects male attractiveness. To our knowledge, this is the first direct evidence for a hypothesized agent of countergradient sexual selection.

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