X-Message-Number: 26801
Date: Fri, 12 Aug 2005 08:58:46 -0700 (PDT)
From: Doug Skrecky <>
Subject: 187'th update on fly longevity experiments

     This is the 187'th update of my fly longevity experiments. Average
 temperature was 25.5 C during this run. Estimated maximal longevity using
 the formula (363 - T*11.2) is 77 days.
     In run #183 I examined the joint effect of various citric acid doses
 to both the breeding and run bottles. However the breeding bottles used
 had been seeded with adult flies, and the next generation had not been
 born yet, so that run effectively tested the effects of citric acid on
 late (run bottle) life versus early (breeding bottle) life. In run #183
 citric acid levels in breeding bottles had no effect, but a low 1/8 tsp
 dosage was beneficial in the run bottles. I concluded that only old flies
 benefit from citric acid.
     This run uses the same three breeding bottles, after the next
 generation was born. Unfortunately the current results appear largely
 random, possibly because too few flies were available to generate decent
 survival curves.
     Citric acid at a 1/8 tsp dosage has been a standard additive for some
 time, because flies have in the past have tended to live longer when
 citric acid was used. I'm now wondering if bacteria are evolving some
 resistance to this acid. Run #200 is looking at a possible alternative to
 citric acid.

 Run #187              Percent Survival on Day
 supplement             5  12 20 28 38 45 55 62 71
 _________________________________________________
 citric (0) 0 tsp      88  75 63 25 13  4  0  -  -
 citric (0) 1/8 tsp    96  57 48 44 22 13  4  0  -
 citric (0) 1/4 tsp    91  73 64 41  9  5  5  0  -
 citric (1/8) 0 tsp   100 100 67 50 42 17  8  0  -
 citric (1/8) 1/8 tsp 100  70 60 30 10 10  0  -  -
 citric (1/8) 1/4 tsp  73  40 27  0  -  -  -  -  -
 citric (1/4) 0 tsp   100  91 86 48 29 19  0  -  -
 citric (1/4) 0 tsp    83  54 46 25 17  4  4  4  0
 citric (1/4) 1/8 tsp  96  58 50 33 13  8  0  -  -
 citric (1/4) 1/8 tsp  96  82 75 54 32 18  7  0  -
 citric (1/4) 1/4 tsp  80  60 68 48 24  8  4  0  -
 citric (1/4) 1/4 tsp 100  96 68 52 28 20  4  0  -

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