INDUCED BREEDING 



109 



Triturua: (pyrrhogaeter, torosus or vlridescens) 



These newts can "be kept in the lahoratory for long periods, are fed on liver and 

 earthworms, and can be Induced to ovulate either with amphibian (E. pipiens) pituitaries 

 or with mammalian extracts of the anterior pituitary hormone. Spermatophores are retained 

 for many months and (particularly with T. pyrrhogaster, the Japanese newt) the majority of 

 females will give fertile eggs almost any time. The breeding tanks for Urodeles should be 

 shallow, with facilities for their climbing out onto floating pieces of wood or onto sand. 

 Aq.uatic' plants (Elodea) should be provided not only for aeration but for the attachment of 

 eggs. Efegs will be layed singly, in large Jelly capsules, and will always be attached to 

 plants. Instead of injecting large doses of pituitary it is well to inject about two fe- 

 male (frog) glands per day for several days since Urodele eggs are constantly maturing. 

 If the animals are well fed they may be Induced to lay a few eggs per day over long 

 periods. 



Ambystoma : (mexicanum, opacum, punctatum, tigrlnum) 



The'se species apparently do not retain their spermatophores for very long before ovu- 

 lation, hence it is generally more practical to collect the eggs in nature. Ambystoma 

 opacum eggs are available late in September; A. punctatum and tigrlnum eggs from January 

 through May; and A. mexicanum eggs In the spring, time variable. 



A. punctatum males will drop their spermatophores in slowly running streams or in 

 ponds during the late March rains even when the temperature may be as low as 15°C., several 

 days prior to the migration of the females from the woods. Females captured after they 

 pick up spermatophores, but before ovlposltlon, will lay their eggs in the laboratory 

 spontaneously or under pituitary stimulation. 



The eggs of A. opacum and A. punctatum are excellent for operative procedures because 

 they develop rather slowly and are very hardy. The eggs of A. tigrlnum are hardy but 

 develop very rapidly, while the axolotl (A- mexicanum) eggs do not stand operative proce- 

 dures very well. 



OBSEBVATIONS AND TABULATION OF DATA : 



With each attempted Induction of ovulation the following data should be recorded: 



1. Number and source of anterior pituitary glands. 



2. Physiological condition of recipient, i.e., size, evidence of sexual maturity, 

 and extent and conditions of laboratory confinement. 



5. Temperature at which the injected female was kept. 



k. Date of injection and date or time of appearance of the first eggs within the 



uteri . 

 5. Percentage ovulation, determined by estimate of the volume of eggs remaining 



in the ovary after the reaction has been completed. 



