LD50 FOR FRUIT FLIES -Reply

[FRAMEP@ORAU.GOV]

Some time ago, Paul Skierkowski requested info on the LD50 for
Drosophila melanogaster.

One table I have (of unknown origin) gives the LD50 for Drosophila at
approximately 100,000 rad.

There is a paper in Nucleonics Dec 1952 p 42 by Hassett and Jenkins
that provides the following info regarding Drosophila melanogaster:
 "using x-rays found that 180 r killed 50% of young (approximately 3 hr)
Drosophila eggs. Dittrich et al found that X-rays were more effective
than fast electrons when Drosophila eggs over 3 hr old were
treated...resistance to radiation increases steadily with development, for
the LD-50 was 200 r for 3 hr old eggs, 500 r for 4 hr eggs, 810 r for 7.5
hr eggs, and 2800 r for pupae"

At 1300 r/hr using Ta 182 as the gamma source "90% of adult Drosophila
were killed by exposure to 84,000 r".

At 193,000 r/hr using Co-60, all adults were dead within 2 days of
193,000 r, 

At 64,000 r some survived 3 weeks but were sterile. 

The paper doesn't specify a LD-50  but given all the variables, a guess of
50,000 to 60,000 r might not be too far off. 

Best wishes

Paul Frame
Professional Training Programs
ORISE
framep@orau.gov