题目：Theory of stoichiometric intraguild predation: algae, ciliate, and Daphnia

主讲人：原三领

时间：2024年12月6日星期五上午9:00

地点：腾讯会议（383-655-368）

主办单位：理学院

主讲人简介：

原三领，上海理工大学教授，博士生导师，中国数学会生物数学专业委员会副主任。研究方向为：微分方程与动力系统、生物数学。曾先后主持多项国家自然科学基金面上项目和上海市项目的研究工作。研究内容涉及微分方程与动力系统、种群动力学、流行病动力学、海洋生态学以及生物化学工程等诸多领域，具有多学科交叉的特点。曾多次受邀到国内和国际多所高校进行合作研究和学术交流，在SIAM Journal on Applied Mathematics、Journal of Mathematical Biology、Journal of Differential Equations等国内外重要学术刊物上发表SCI论文100余篇。

摘要：

Consumers respond differently to external nutrient changes than producers, resulting in a mismatch in elemental composition between them and potentially having a significant impact on their interactions. To explore the responses of herbivores and omnivores to changes in elemental composition in producers, we develop a novel stoichiometric model with an intraguild predation structure. The model is validated using experimental data, and the results show that our model can well capture the growth dynamics of these three species. Theoretical and numerical analyses reveal that the model exhibits complex dynamics, including chaotic-like oscillations and multiple types of bifurcations, and undergoes long transients and regime shifts. Under moderate light intensity and phosphate concentration, these three species can coexist. However, when the light intensity is high or the phosphate concentration is low, the energy enrichment paradox occurs, leading to the extinction of ciliate and Daphnia. Furthermore, if phosphate is sufficient, the competitive effect of ciliate and Daphnia on algae will be dominant, leading to competitive exclusion. Notably, when the phosphorus-to-carbon ratio of ciliate is in a suitable range, the energy enrichment paradox can be avoided, thus promoting the coexistence of species. These findings contribute to a deeper understanding of species coexistence and biodiversity.