DIAPAUSE IN BUPALUS PINIARWS L {LEP., GEOMETRIDAE) 

 Ж RELATION TO HOST — PARASITE SYNCHRONIZATION 



Диапауза у Bupalus piniarus (Lep., Oeometridae) и синхронизация 

 развития хозяина и паразита 



L. М. SCHOONHOVEN 



(Laboratory of Entomology, Agricultural University, Wageningen, Netherlands) 



The Pine Looper, Bupalus piniarius L. {Geometridae), hibernates as a pupa 

 and performs its metamorphosis in spring. Tliough competence for adult 

 development is already present immediately after the pupal moult, the rate 

 of metamorphosis is increased after exposure of the pupa to low temperatures. 



rate of development of Bupalus 



days at 25° 



Fig. 1. Rate of pupal development after a chilling period. 



Chilling experiments. In our experiments the pupae were placed 

 at the low temperature (3°C.) directly after pupation. Fig. 1 shows the action 

 of chilling on the rate of development at 25°C. A positive correlation can be 

 observed between the duration of the chiUing period and the rate of develop- 

 ment. This means that the processes which precede metamorphosis and perhaps 



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