Chamberland Valérie F, Latijnhouwers Kelly R W, Huisman Jef, Hartmann Aaron C, Vermeij Mark J A
Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Science Park 700, 1098 XH Amsterdam, The Netherlands
SECORE International, 4673 Northwest Parkway, Hilliard, OH 43026, USA.
Proc Biol Sci. 2017 Jun 28;284(1857). doi: 10.1098/rspb.2017.0852.
Many marine invertebrates provide their offspring with symbionts. Yet the consequences of maternally inherited symbionts on larval fitness remain largely unexplored. In the stony coral (Esper 1797), mothers produce larvae with highly variable amounts of endosymbiotic algae, and we examined the implications of this variation in symbiont density on the performance of larvae under different environmental scenarios. High symbiont densities prolonged the period that larvae actively swam and searched for suitable settlement habitats. Thermal stress reduced survival and settlement success in larvae, whereby larvae with high symbiont densities suffered more from non-lethal stress and were five times more likely to die compared with larvae with low symbiont densities. These results show that maternally inherited algal symbionts can be either beneficial or harmful to coral larvae depending on the environmental conditions at hand, and suggest that mothers use a bet-hedging strategy to minimize risks associated with spatio-temporal variability in their offspring's environment.
许多海洋无脊椎动物会为它们的后代提供共生体。然而，母体遗传的共生体对幼体适应性的影响在很大程度上仍未得到探索。在石珊瑚（埃斯珀，1797年）中，母体产出的幼体所含的内共生藻类数量差异很大，我们研究了这种共生体密度变化在不同环境情景下对幼体表现的影响。高共生体密度延长了幼体积极游动并寻找合适附着栖息地的时间。热应激降低了幼体的存活率和附着成功率，其中高共生体密度的幼体比低共生体密度的幼体更容易受到非致命应激的影响，死亡可能性高出五倍。这些结果表明，母体遗传的藻类共生体根据当前的环境条件对珊瑚幼体可能有益也可能有害，并表明母体采用了一种风险对冲策略，以尽量减少与后代环境时空变异性相关的风险。
