Dairy Products Added to Rearing Media Negatively Effect Drosophila melanogaster (Diptera: Drosophilidae) Egg Production and Larval Development

This study examined the effect of kefir, yogurt, and milk on egg production and development in Drosophila melanogaster Meigen. Kefir, yogurt, and milk were added to the Drosophila culture medium. First they were fed to mature individuals and then these females laid eggs on medium containing kefir, yogurt, and milk. Later the development of eggs and larvae was examined. The experiments were conducted on two generations, the F(1) generation reared with additives in the media and F(2) without the additives. The effects of these substances on the basic stages of development were also examined. In the experimental groups, the numbers of eggs and larvae decreased considerably in both the F(1) and F(2) generations. The comparison between the experimental groups themselves also showed a difference. In both generations, development of eggs into third instar larvae was reduced and metamorphosis was delayed. In addition, morphological abnormalities were observed in the larvae. Overall the results showed that kefir, yogurt, and milk affected egg and larva development negatively and this negative effect continued in the F(2) generation. The continuation of this negative effect in the F(2) generation, which was not exposed to various milk additives, is an interesting finding. These results indicate that the nutrients from the milk and the milk products used were neither utilized by nor beneficial for this insect.