> Dear Dr. Jeong,
>>> Propionic acid can act as a stress factor in drosophila melanogaster. We
> use propionic acid as an antimicrobial agency, and found that under
> conditions it strongly reduces larval survival. That is under high
> illumination (400 lx) by visible light survival decreases. A low
> illumination (40 lx) does not have this effect. Without propionic acid in
> the food visible light not affect larval survival. The effect of light on
> survival is dependent on the yeast concentration in the food (Insect
> Biochemistry 21: 535 and 541).
> We found that a direct light treatment of larvae scarcely affected
> survival. The effect of light on survival is based on changes in the
> food. We showed that light degrades the essential vitamin riboflavin.
> causes a vitamin defieciency, and thus mortality.
> The noxious effect of light is prevented by the addtion of antioxidants
> (vitamin C, uric acid, carotene, tryptophan) to the food.
> Besides, acetic acid acts in a similar way: it enhances light induced
> The effect of light is dependent on the strain. Under illumination by
> visible light survival of a Tanzania strain was higher than that of a
> Norwegian strain. The mutants yellow and ebony showed a similar survival
> response under high illumination.
> These results are found under laboratory conditions. Fermenting fruit is
> natural breeding site of Drosophila. These sites do contain acetic acid
> enhancer of light induced mortality) and vitamin C (an inhibitor).
> whether noxious effects of visible light also occur under natural
> conditions is not known to me.
> Light treatment of the yeast food generates hydrogen peroxide. That is
> probably also the cause of the elevated lipidperoxide levels in the
> food under high illumination.
> Propionic acid also affect pupation behavior: it heightens pupation sites
> (DIS 75:92).
> This work was part of my PhD thesis at the Utrecht University (The
> Netherlands). I hope yoy can use this information. If you are interested
> more details I can send you a copy of my thesis.
>>> Yours sincerely,
> padualaan 8
> 3584 CH Utrecht
> The Netherlands