Studies in aging. II. The effects of injecting hemolymph from younger and older donors on the fecundity and the adult life span of hosts in drosophila
✍ Scribed by Sondhi, K. C.
- Publisher
- John Wiley and Sons
- Year
- 1966
- Tongue
- English
- Weight
- 593 KB
- Volume
- 162
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Attempts were made to study the effects on Swedish inbred Drosophila melanogaster females of replacing equivalent volumes of hemolymph from younger and older donors of the same strain. The physiological effects on hosts were studied by examining the fecundity and the adult life span.
Nine-to ten-day-old hosts, receiving 0.25 p1 of hemolymph from 34-day-old donors, do not differ appreciably either in fecundity or longevity from the controls. Similarly, 12-13-day-old hosts, undergoing replacements of 0.25 p1 and 0.50 pl of hemolymph from freshly emerged donors, fail to show an improvement in the egg production or in the life span. It is suggested that the hemolymph donated by younger females lacks the properties that are associated with a higher fecundity or a higher expectation of life.
Freshly emerged hosts, in which 0.25.1.41 of hemolymph from 12-13, 16-17 and 23-24-day-old hosts was replaced, undergo a remarkable life-shortening without a decrease in the egg production. In individuals, deprived of 0.25.d of hemolymph, similar results are obtained; that is, only reduction in the life span is realized, the fecundity being unaffected.
The reduction in the life span of hosts injected with the hemolymph from older females is explained as due to the presence of deleterious factors in the hemolymph of older individuals, Such factors are considered in terms of "accumulation and depletion phenomena" commonly observed in insects. The absence of reduced egg production in females under stress is interpreted as due to homeostatic mechanisms which tend to insure the period of active reproduction. The bearing of these results on the evolution of life span in organisms is discussed.