X-Message-Number: 26061
References: <>
From: Kennita Watson <>
Subject: Re: 172'nd update on fly longevity experiments
Date: Wed, 20 Apr 2005 10:59:00 -0700

Doug Skrecky <> wrote:
> Subject: 172'nd update on fly longevity experiments
> ...     According to one survey, cranberry has the highest oxygen 
> radical
>  absorbance capacity (ORAC) among fruits and vegetables, while cloves 
> have
>  the highest ORAC of all food items....
>      To my great surprise, the current batch of clove powder turned 
> out to
>  be highly toxic. I have no idea why this turned out to be the case. 
> ...

>  Run #172                    Percent Survival on Day
>  supplement          12 26 33 45 55 64 71 78 83 87 91 95 101
>  ___________________________________________________________
>  control one         95 58 53 37 26 16  5  5  5  5  0  -   -
>  control two         88 56 44 36 36 16  8  0  -  -  -  -   -
>  cloves 1/8 tsp      52  0  -  -  -  -  -  -  -  -  -  -   -
>    "    1/4 tsp      29  0  -  -  -  -  -  -  -  -  -  -   -
> ...

Question:  How long do flies live if you don't feed
them anything at all?  Could the poor results from
cloves be not because they're toxic, but because
flies don't consider them food?  (It may also be
that 1/16 or 1/32 tsp would confer benefit; I
certainly don't think I'd respond well to eating a
cup of cloves.)

In attempting to answer this question for myself, I
ran across <http://www.kabt.org/Labs/Fruit%20Fly.htm>
which said " If the food becomes too dry, the animals
starve. They need to watch for 'cracked' and dry food
and/or lifeless larvae. If this occurs, adding one or
two drops of water will moisten the food and should
solve the problem. On the other hand, the environment
can become too humid and the food too moist. In this
case the food will become contaminated with fungi,
which is also detrimental to the flies. Finally,
caution students not to leave the flies in direct
sunlight or other extreme environmental conditions."
(FYI: the activity above was based on a set of
activities detailed at
http://www.is.wayne.edu/mnissani/PAGEPUB/FLIES.HTM .)

I expect/hope that you've set up the room (the flies
are all in one room, right?) to not be exposed to direct
sunlight (heavy curtains and/or northern exposure).

Could some supplements be better at wicking moisture
to the surface of the food, so it dries out faster and
the flies starve -- or at holding in the moisture, so
fungus grows?

"Longevity-enhancing Effects of Bacterial Exposure in
Fruit Flies "
"Bacterial exposure can increase longevity, but only
when it occurs early in life. ..."

The more I read, the  more it seems that the
experiments you report on are insufficiently
controlled.  A set of more controlled experiments
is detailed at
http://www.pnas.org/cgi/content/full/101/35/12980 .

Confusion:  I haven't seen anything online that
discusses fruit fly lifespans longer than 80 days.
Apparently it's normally about 35, and most articles
talk about lengthening it with calorie restriction,
lowered temperature, etc. to about 72.  Where does
a maximal longevity of 123 days come from, then?

I should stop -- I've been at this for almost two
hours.  I hope I've offered some food for thought.
(I wonder if a local school's biology teacher could
be enlisted to have his/her class do some of the

Thanks, Kennita

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