16 



BULLETIN 231, U. S. DEPARTMENT OF AGRICULTURE. 



From this evidence it seems clear that one copulation will often result 

 in fertilization, but will not usually suffice for complete fecundity of 

 the female. 



Fecundity of females of A. grandis with complete record on copula- 

 tion. — Since very little was known concerning the exact number of 

 times a single female will copulate in the course of her life an attempt 

 was made to secure some information on this point. 



Nine females were separated from the males immediately after 

 emergence and each was fed separately throughout life. A male was 

 allotted to each female and each day the different pairs were placed 

 together in dry glass tubes for a short time while under close observa- 

 tion and given a chance to copulate. The period spent in copula was 

 noted each time and in this manner a complete record of the copula- 

 tions of each female was secured. During the remainder of the day 

 the females were kept on fresh squares and the daily egg deposition 

 noted. The results secured in this series are shown in Table VII. 

 Table VII. — Fecundity of females of A. grandis with complete record of time in copula. 



Oviposition. 



Total, average, etc. 



Times | Total 



in cop- time in 



ula. | copula. 



Min. 



6s9. 

 650.5 

 563.0 

 369.0 

 291.5 

 196.0 



time 



per 



copula. 



Mln. 

 22.3 

 22.2 

 23.8 

 25.5 

 22.4 

 23.4 

 20.5 

 22.4 

 21.7 



Started. 



July 2 

 July 4 



...do 



Julv 5 

 July 6 

 July 7 



...do 



Julv 9 

 Julv 11 



Ended. 



Period 



Julv 29 

 Aug. 9 

 Aug. 24 

 Aug. 4 

 Aug. 12 

 Aug. 6 

 Aug. 7 

 Aug. 5 

 Aug. 27 



Days. 

 28 

 37 

 52 

 31 

 38 

 31 

 32 

 28 

 17 



Total 205 



Average 



Weighted average 



Maximum 



Minimum 



22.7 



33 



4,703.5 . 

 522. 6 ! 



22.9 



294 

 32. 



7S6.5 

 196.0 



25.5 

 20.5 



Total 



number 



eggs. 



204 



217 



302 



112 



126 



126 



- 208 



65 



32 



Eggs 

 de- 

 pos- 

 ited 

 exter- 

 nallv. 



1,392 

 154.' 



302 

 32 



Aver- Max- 

 age imum 

 num- num- 

 ber { ber 

 eggs eggs 

 per per 

 dav. I dav. 



o. a 

 3.6 

 3.3 

 4.0 

 6.5 

 2.3 

 1.9 



7.3 

 1.9 



18 



The number of times a single female will copulate was found to be 

 much higher than was anticipated. With these 9 females the num- 

 ber varied from 9 to 33, with 6 females copulating more than 20 

 times. The average per female was nearly 23 times. 



In spite of the great number of copulations the number of eggs 

 deposited by these females was not high in comparison with other 

 series. It may be that the fact that the females were of necessity 

 removed from their food for from 1 to 2 hours daily while with the 

 males had some effect on the egg deposition. The total number of 

 eggs per female varied from 32 to 302, with an average of 154.7 eggs 

 per female. This average is considerably lower than that for the 

 females fertilized only once The average number of eggs per female 

 per day was 4.7, which is also lower than the average for the once 

 fertilized females. 



