METABOLISM DURING DIAPAUSE AND DEVELOPMENT IN SAWFLY 

 METAiMORPHOSIS 



Метаболизм стадий пронрап^ония пилмлыцнков в течение диапаулы и развития 



К. SLAM А 



(Entomological Laboratory of Czechoslovak Academy of Sciences, 

 Praha, Czechoslovakia) 



In the present communication I should like to describe briefly some of the 

 experiments performed on metamorphosis stages of different saw^lies which 

 seem to be interesting from the physiological point of view. 



It is generally recognized in the insect physiology that the respiratory 

 metabolism of the pupal stage is characterized by a variously modified U-shap- 

 ed curve of the oxygen consumption (see Wigglesworth, 1953, Edwards, 

 1953). In sawfly metamorphosis may be seen a similar U-shaped course 

 of respiration. Unlike the other holometabola in which these changes take 

 place in the pupal stage, the typical U-shaped curve of metabolism in sawfly 

 metamorphosis is divided between both the prepupal stages and the pupa. 

 Metabolic processes taking place in the initial stage of the pupal development 

 of holometabola occur in sawflies during the prepupal stages which are of con- 

 siderable importance. An adult sawfly larva does not accept food after the last 

 larval moulting and transforms directly into the first prepupal stage — eo- 

 nymph. At the end of eonymphal stage histogenetical processes in imaginai 

 discs as well as histolysis of the larval body parts begin to assert themselves 

 causing the formation of the further prepupal stage — pronymph. Generally 

 speaking, eonymph keeps the larval body structure, while pronymph displays 

 already internal organs of imago, which in other holometabola develop as late 

 as in the pupa. In sawfly pupa living relatively for a short time the deffinitive 

 formation of imaginai organs is completed. Presumably the prepupal stages 

 form here a further, that is the third instar of metamorphosis divided by an 

 interposed moulting from the pupa, while the instar preceding eonymph 

 corresponds in sawflies to the last larval instar of other holometabola. Just 

 before the last larval moulting (i. e. eonymphal moulting) feeding is usually 

 finished and growth of the larval body stopped) see preceding report on the 

 origin of the pupal instar by Novak and Slam a). 



Eonymphal — pronymphal transformation accompanied by histogenesis 

 of imaginai discs and histolysis of the larval body is very important from the 

 physiological point of view. In some species as in Cephalcia abietis L. this 

 period is distinctly limited by eonymphal and pronymphal diapause (Novak 



1^' 195 



