The Biology of Senescence 



to the period of starvation, but that individuals starved only 

 until the 11th or 17th instar lived longer than individuals 

 starved throughout life. This prolongation of life was achieved 



100 

 90 

 80 

 70 



60 

 50 



40 

 30 



20 



2 ■ 



»AWWWW4 



Well fed (normal) 



Starved until 6th instar 



Starved until 9th instar 



Starved until 12 th instar 



Starved until 15th instar 



Starved throughout life 



O Mean Longevity 



DAYS OF LIFE 

 1 1 ■ 



\ 



15 



20 



25 



30 35 



40 45 



50 55 60 



Fig. 37. — Effect of restricted food upon the longevity of Daphnia longispina 

 (from Ingle, Wood and Banta, 1937). 



by lengthening the duration of each retarded instar, the total 

 number of instars remaining constant. In this species (D. 

 longispina) the specific age appeared to lie between the 19th and 



144 



