Storage fungi antagonistic to the flour mite (Acaras siró L.).
The following is based on the authors' summary. Under favourable physical conditions, populations of Acarus siró L. reared on sterilised wheat-germ flakes normally eat the whole of the food supply and then die out unless the wheat is replenished. Sometimes, however, the germ becomes discoloured (brown) and the mites die out leaving the greater part of it uneaten. The discoloration and the premature failure of the mite populations were both found to be caused by the xerophüic mould Sporendonema sebi. Aspects of the population decline were reduced reproduction, high mortality and retarded development. Since the antago-nistic effect was not noticeably diminished when the medium had again been sterilised, it must be possible for it to be exerted either by the dead fungus or through an effect of the fungus on the food (or both). Another xerophüic fungus, Aspergillus restrictos, also caused premature failure of the mite population but a different discoloration of the germ flakes. After the infected material had been re-sterilised, the mites consumed almost all of it, but abnormally slowly. Although this mite, like related species, feeds on many moulds, some are evidently harmful to it, either because they are themselves poisonous or because they exert some harmful effect upon the main food supply.