158 I. HARPAZ 



J Z. AviDOV, Ktavim, 2-3 (1952) 43. 



5 R. C. Dickson, Ann. Entomol. Soc. Am., 42 (1949) 511. 



^ I. Harpaz, Unpublished results. 



■ H. H. Clayton and F. L. Clayton, World weather records, 1931-1940, 



Smithsonian Institution, Washington, D.C., 1947. 

 ^ S. Yathom, Ph. D. Thesis, Hebrew University, Jerusalem, 1959. 

 9 M. Miles, Bull. Entomol. Research, 49 (1958) 405. 



10 F. Schneider, Mitt. Schweiz. Entomol. Ges., 21 (1948) 249. 



11 I. Harpaz, Ph. D. Thesis, Hebrew University, Jerusalem, 1953. 



1- F. S. Bodenheimer and P. M. Vermes, Studies in Biology, Jerusalem, 

 1 (1957) 106. 



DISCUSSION 



Lees: I do not think it profitable to argue whether it is an 

 example of diapause or quiescence; everybody should be allowed 

 to make up his own mind on this point. My question refers to 

 Gambaro's work in Italy. She believes that the maturity and the 

 variety of the apple has a considerable influence on diapause in 

 the codling moth. Is your Baghdad race affected similarly? 



Harpaz: There is no synchronisation between the phenology 

 of our apple trees and that of the codling moth. When the insect 

 emerges before the fruit is available, it finishes its larval develop- 

 ment entirely on leaves. 



Hestrin: You have suggested that the induction of diapause 

 prior to nutritional deficiency is a useful characteristic; but how 

 does selective pressure in evolution produce an anticipatory 

 mechanism? 



Harpaz : This was only a suggestion. I feel it must be cumula- 

 tive over a period of time, you cannot induce diapause by shock 

 treatment. 



Lees: I do not see any great difficulty here. If natural selection 

 weeds out the animals which do not enter diapause, 'antici- 

 patory' mechanisms would surely be evolved rather rapidly. 



