X-Message-Number: 26686
Date: Sun, 24 Jul 2005 15:33:33 -0700 (PDT)
From: Doug Skrecky <>
Subject: 183'rd update on fly longevity experiments

     This is the 183'rd update of my fly longevity experiments. Average
 temperature was 22.7 C during this run. Estimated maximal longevity using
 the formula (363 - T*11.2) is 109 days.
     In run #165 I compared the joint effect of addition of various doses
 of citric acid both to breeding bottles, as well as to bottles used in
 the run itself. In that run an unusually high longevity characterized run
 bottles containing 1/8 tsp citric acid, that had been seeded from a
 breeding bottle which used a higher 1/4 tsp dosage. This may have been a
 chance effect due perhaps to a relative (but accidental) lack of
 pathogens in this bottle, or it may have been a real causal effect of
 citric acid, possibly due a direct antipathogen effect of the acid. This
 run seeks to take a second look at breeding bottle citric acid levels,
 while the breeding bottles are still too young to have yielded many
 offspring flies.
     A run bottle dosage of 1/8 tsp citric acid was found to be
 beneficial, when the breeding bottles contained either no, or a medium
 1/8 tsp citric acid dosage. However in this run no benefit was seen when
 the breeding bottle containing citric at a higher 1/4 tsp dose was used.
 This high a level of acid has been observed to inhibit reproduction, so
 all the flies from this bottle might all be parents, with no offspring.
     I conclude that citric acid levels in breeding bottles have no
 significant effect on parent fly longevity. These same breeding bottles
 will be looked at again in run #187, after a longer incubation period, to
 test for offspring effects.

 Run #183              Percent Survival on Day
 supplement            12 20 30 38 44 51 59 68
 _____________________________________________
 citric (0) 0 tsp      61 44 39 33  6  6  0  -
 citric (0) 1/8 tsp    60 60 53 47 13  7  7  0
 citric (0) 1/4 tsp    62 45 35 24 14  3  0  -
 citric (1/8) 0 tsp    58 32 26 11  5  5  0  -
 citric (1/8) 1/8 tsp  50 50 30 25 20  5  0  -
 citric (1/8) 1/4 tsp  92 77 23 15  8  0  -  -
 citric (1/4) 0 tsp    68 53 37 32 16  5  5  0
 citric (1/4) 1/8 tsp  68 37 32 21 21  5  0  -
 citric (1/4) 1/8 tsp  56 33 22 17 11  6  6  0
 citric (1/4) 1/4 tsp  73 53 40 27 13  0  -  -
 citric (1/4) 1/4 tsp  57 43 24 14  5  5  0  -

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