Effect of temperature and food type on asexual reproduction in Aurelia sp.1 polyps
2015
Wang, Yan-Tao | Zheng, Shan | Sun, Song | Zhang, Fang
Environmental factors such as temperature and food type affect the rate of asexual reproduction of jellyfish at the polyp stage. Combinations of three temperatures (10, 15, and 20°C) and four food treatments (Prorocentrum donghaiense, Skeletonema costatum, Artemia sp. nauplii, and no food) were established to examine the asexual reproduction strategy of Aurelia sp.1. The results allowed us to reject two null hypotheses: no effect of temperature and no effect of food. A change from 20 to 15 or 10°C induced polyps to release ephyrae when food was present, while polyps without food did not strobilate. Polyps with Artemia sp. nauplii as prey produced more polyps through buds and podocysts, as well as more ephyrae through strobilation. At 20°C, the mortality rates of polyps exceeded 50%, except for those served by Artemia sp. nauplii. The number of polyps increased rapidly with Artemia sp. nauplii as prey. We conclude that when animal prey is limited, plants can serve as a nutrient source and satisfy the energy requirements for polyps at lower temperatures (10 or 15°C). Phytoplankton cannot provide adequate nutrition to polyps at higher temperature (20°). Abundant animal prey and suitable temperatures are essential conditions for polyps to strobilate and release ephyrae, leading to jellyfish blooms.
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