Department of Evolutionary and Environmental Biology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, 3498838, Haifa, Israel.
National Institute of Oceanography, Tel Shikmona, P.O. Box 8030, 31080, Haifa, Israel.
Sci Rep. 2022 Sep 6;12(1):15117. doi: 10.1038/s41598-022-18550-9.
Each of the few known life-history strategies (e.g., r/K and parity [semelparity and iteroparity]), is a composite stratagem, signified by co-evolved sets of trade-offs with stochastically distributed variations that do not form novel structured strategies. Tracking the demographic traits of 81 Botryllus schlosseri (a marine urochordate) colonies, from birth to death, we revealed three co-existing novel life-history strategies in this long-standing laboratory-bred population, all are bracketed through colonial fission (termed NF, FA and FB for no fission, fission after and fission before reaching maximal colony size, respectively) and derived from organisms maintained in a benign, highly invariable environment. This environment allows us to capture the strategists' blueprints and their net performance through 13 traits, each branded by high within-strategy variation. Yet, six traits differed significantly among the strategies and, in two, the FB was notably different. These results frame fissions in colonial organisms not as demographic traits, but as pivotal agents for life-history strategies.
每种已知的少数生活史策略（例如，r/K 和均等[单性生殖和多次生殖]）都是一种复合策略，其特征是与随机分布的变化共同进化的权衡取舍，这些变化不会形成新的结构化策略。通过跟踪 81 个海洋尾索动物（海鞘）群体从出生到死亡的人口统计特征，我们在这个长期实验室繁殖的种群中发现了三种共存的新的生活史策略，所有这些策略都通过群体分裂（分别称为 NF、FA 和 FB，代表不分裂、分裂后达到最大群体大小和分裂前达到最大群体大小），并且源自于在良性、高度不变的环境中维持的生物体。这种环境使我们能够通过 13 个特征来捕捉策略制定者的蓝图及其净表现，每个特征都具有高度的策略内变异性。然而，有六个特征在策略之间存在显著差异，其中两个 FB 明显不同。这些结果将群体生物中的分裂不是作为人口统计特征，而是作为生活史策略的关键因素。
