19 



This paper reports an X-Y (XY=male, XX=female) sex chromosome 

 mechanism in Cnemidophorus tigris gracilis and points out that most 

 species in the genus lack readily recognizable heteromorphic pairs of 

 chromosomes. 



*8. — . and C. R. Townsend. 1977. Parthenogenetic reptiles: new 

 subjects for laboratory research. EXPERIENTIA 33(3): 285-289. 



A detailed description of laboratory procedures necessary to suc- 

 cessfully raise parthenospecies of Cnemidophorus through multiple gener- 

 ations is given. C^. exsanguis was used primarily, and raised through ii- 

 generations. Other species mentioned were neomexicanus, sonorae , tes- 

 selatus and velox , as well as the sexual species inornatus , sexlineatus , 

 and tigris . The significance of this capability for future biological 

 research is discussed. 



49. Congdon, 3. D., L. 3. Vitt and N. F. Hadley. 1978. Parental in- 

 vestment: comparative reproductive energetics in bisexual and unisexual 

 lizards, genus Cnemidophorus . AMERICAN NATURALIST 112: 509-521. 



Reproductive energetics for _C. inornatus , C. sonorae , C. tigris 

 and C. uniparens from Arizona were estimated from caloric whole body and 

 egg content. Clutch size was larger in unisexual species and in larger 

 species within a reproductive type. Calories/mg. of eggs were not cor- 

 related with either body size or reproductive type; differences in 

 clutch volume between species superceded differences in caloric content 

 of eggs per unit weight. Mean calories per egg were higher in large- 

 bodied lizards and in bisexual lizards independent of size. The clutch 

 calories/body calories ratio was significantly higher in unisexual spe- 

 cies, and this fact is discussed. Data suggest that the nature of the 

 competitive environment and the degree of genetic similarity among in- 

 dividuals are important evolutionary determinants of the apportionment 

 of energy to reproduction and the compromise between egg size and num- 

 bers in whiptail lizards. 



50. Crews, D. and K. T. Fitzgerald. 1980. Sexual behavior in par- 

 thenogenetic lizards (Cnemidophorus ). PROCEEDINGS OF THE NATIONAL 

 ACADEMY OF SCIENCES USA 77(1): ^99-502. 



Captive Cnemidophorus tesselatus, _C. uniparens and _C. velox ex- 

 hibit behavior patterns remarkably similar to the courtship and copu- 

 latory behavior of closely related sexual species. The courted animal 

 was reproductively active in each instance while the courting animal was 

 either reproductively inactive or postovulatory. This behavior may re- 

 present a nonfunctional vestige of sexual ancestry or be necessary to 



