The effect of food, light intensity and tank volume on resting eggs production in Daphnia carinata

摘要

Sexual reproduction is an important stage of cyclical parthenogenesisDaphnia, these cyclic parthenogens need to time their shift from asexual to sexual reproduction correctly, based on environmental cues. We investigated the effect of food quality and quantity, light intensity, and culture tank volume on the resting eggs production of a tropicalDaphnia carinataclone of Vietnam. The results showed that sexual ephippia production of theD. carinatawas strongly induced when fed with green algaeScenedesmussp., under moderate light intensity condition. The experiments also showed that food limitation is not an obligate requirement of shifting from parthenogenetic reproduction to sexual ephippia reproduction inD. carinata.Beside of that, culture volume seemed to be an important determinant of successfully forming of embryos inside ephippium. These findings here were from cultures in contaminant free condition, thus they are important basics for further studies of additional effects of environment toxicants onD. carinataspecies of Vietnam.