X-Message-Number: 17713
Date: Sat, 6 Oct 2001 19:50:08 -0700 (PDT)
From: Doug Skrecky <>
Subject: 48'th update on fly longevity experiments
This is the 48'th update of my fly longevity experiments. All bottles
contain 1/4 tsp citric acid as a standard additive. Here I examine the
effect of removing the corpses of dead flies at each census. Since I do
not have access to CO2 gas, I placed the "no corpse" bottles in my fridge
to temporarily reduce fly movement, so that corpses can be removed without
live flies also escaping. One fly did escape during the day 9
census from the "no corpse 3" bottle, but the survival statistics were
adjusted accordingly. Control bottles were also placed in the fridge as
well at the same time so as to act as true controls.
The population density in breeding bottles is much higher than in the
bottles I use for longevity experiments. The risk of viral transmission
would correspondingly be much higher in the breeding bottles. It makes
sense that the presence of rotting fly corpses may aid in viral
transmission. However it is not clear to me whether corpses are a risk to
the few flies in each bottle of a longevity run. Here I decide the matter
with an experiment. As can be seen in these results, removal of corpses
has no effect on fly longevity. The variations in survival I attribute
both to random variations in fly ages at the start of the experiment, and
random variations in degree of viral infestation.
In the next run I will examine the effect of various dietary fibers on
longevity.
Run #48 Percent Survival on Day
supplement 5 9 14 19 24 31 36 42 47 52 57 63
_________________________________________________
control 1 94 82 82 82 ? 58 29 6 6 6 0 -
control 2 95 84 68 58 ? 16 5 5 5 5 5 0
control 3 100 100 80 70 ? 55 30 25 10 0 - -
no corpse 1 100 75 70 65 50 30 30 5 0 - - -
no corpse 2 100 78 67 67 50 28 11 11 11 6 0 -
no corpse 3 100 84 56 33 28 11 6 6 0 - - -
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