HORMONES AND MATING BEHAVIOR 



1177 



(scored as nuzzling), mounting, intromis- 

 sion, and ejaculation. 



The ascending order is justified by the 

 circumstance that in both species the ele- 

 ments tend to appear in this sequence dur- 

 ing sexual maturation (Stone, 1924b ; Avery, 

 1925; Louttit, 1929; Webster and Young, 

 1951 j. Except for some cats given maximal 

 sexual experience (Rosenblatt and Aronson, 

 1958a) , the order of disappearance following 

 castration is the reverse of that during de- 

 velopment in the rabbit (Stone, 1932a), 

 hamster (Beach and Pauker, 1949), rat 

 (Stone, 1939a; Beach, 1944b), and guinea 

 pig (Grunt and Young, 1953). The sequence 

 in which the elements reappear in the cas- 

 trated male given androgen is the same as 

 the order of appearance in the maturing 

 animal (Stone, 1939a; Beach, 1944b; Grunt 

 and Young, 1953). 



In the laboratory at Kansas and else- 

 where there has been concern that the same 

 score can be achieved in more ways than 

 one (Clark and Aronson, 1951 ; Valenstein, 

 Riss and Young, 1954; Larsson, 1956). In 

 studies of the guppy, the problem is com- 

 plicated by the fact that excited males 

 copulate with few or no preliminary acts; 

 consequently, the most excited as well as 

 the least excited individuals have low copu- 

 latory scores. During work with the male 

 guinea pig it was found that subjects dis- 

 playing little mounting and having only a 

 few intromissions and possibly an ejacula- 

 tion late in the test period often attain 

 scores no higher than animals displaying 

 much of only the lower measures of be- 

 havior. The possibility that this paradox 

 might seriously lessen the validity of the 

 scoring procedure has been checked. All the 

 sexual behavior displayed during the tests 

 was recorded (Riss, 1955) ; the average 

 scores were then calculated and compared 

 with the average quantity of each measure 

 of behavior and the latency of ejaculation. 

 Inspection of the table prepared by Riss 

 reveals that both methods yielded rank- 

 orders that were essentially the same; con- 

 sequently, the general accuracy of the older 

 method is assumed. It is recommended, 

 however, that in careful studies both meth- 

 ods should be used. 



Soulairac (1952a), Soulairac and Coppin- 



Monthillaud (1951), and Larsson (1956) in 

 their work on the rat departed from the 

 methods for estimating the strength of sex- 

 ual behavior used by Stone, and by Beach 

 during the first 10 to 15 years of his in- 

 vestigational activity. Sixty-minute rather 

 than 10-minute tests were given and espe- 

 cial value was attached to the initial inter- 

 val when the male displays no activity in 

 the presence of the female, the number of 

 intromissions preceding each ejaculation, 

 the duration of each series of copulations, 

 the intromissions per minute, the length of 

 the refractory period following each ejacu- 

 lation, and the number of ejaculations in 60 

 minutes. 



Since the early 1950's, important changes 

 in the procedure have been adopted by 

 Beach and his associates (Beach and Jor- 

 dan, 1956; Beach and Fowler, 1959). More 

 recently similar procedures have been used 

 in studies of the hamster (Beach and Rabe- 

 deau, 1959). Briefly, special observation 

 cages and a recording system were devised. 

 The latter consisted of three manually oper- 

 ated microswitches, each of which activates 

 a marker which records on waxed paper 

 pulled by a constant speed kymograph. 

 Equally, if not more important, is the 

 lengthening of the test until a criterion of 

 sexual exhaustion has been met — in this 

 case the lapse of 30 minutes without any 

 mounting of the incentive female. Data 

 contributing to six measures of sexual ca- 

 pacity are recorded: latency to the first in- 

 tromission, frequency of ejaculation, intro- 

 missions per ejaculation, the frequency of 

 mounts without intromission, the intercop- 

 ulatory interval, and the postejaculatory 

 interval. 



Scoring procedures helpful in the selec- 

 tion of chickens and cattle for breeding 

 have been devised by Wood-Gush and Os- 

 borne (1956) and Bane (1954), but will not 

 be described here. They would be of value 

 in endocrinological studies of behavior in 

 these species. 



Thus far in the discussion of patterns of 

 behavior and scoring methods no reference 

 has been made to the duality of "functions" 

 or ''mechanisms" first noted by Craig 

 (1918) and later given prominence by Nis- 

 sen (1929), Beach (1942e, 1947, 1947-48, 



