Hird Cameron, Jékely Gáspár, Williams Elizabeth A
Scymaris Ltd, Brixham Laboratory, Freshwater Quarry, Brixham, Devon TQ5 8BA, UK.
University of Exeter, Biosciences, Faculty of Health and Life Sciences, Streatham Campus, Exeter EX4 4QD, UK.
R Soc Open Sci. 2024 Sep 18;11(9):240274. doi: 10.1098/rsos.240274. eCollection 2024 Sep.
A free-swimming larval stage features in many marine invertebrate life cycles. To transition to a seafloor-dwelling juvenile stage, larvae need to settle out of the plankton, guided by specific environmental cues that lead them to an ideal habitat for their future life on the seafloor. Although the marine annelid has been cultured in research laboratories since the 1950s and has a free-swimming larval stage, specific environmental cues that induce settlement in this nereid worm are yet to be identified. Here, we demonstrate that microalgal biofilm is a key settlement cue for larvae, inducing earlier onset of settlement and enhancing subsequent juvenile growth as a primary food source. We tested the settlement response of to 40 different strains of microalgae, predominantly diatom species, finding that have species-specific preferences in their choice of settlement substrate. The most effective diatom species for inducing larval settlement were benthic pennate species including , and . The identification of specific environmental cues for settlement enables a link between its ecology and the sensory and nervous system signalling that regulates larval behaviour and development. Incorporation of diatoms into culture practices will improve the husbandry of this marine invertebrate model.
许多海洋无脊椎动物的生命周期中都有一个自由游动的幼虫阶段。为了过渡到栖息在海底的幼体阶段，幼虫需要从浮游生物中沉降下来，在特定环境线索的引导下，找到适合它们未来在海底生活的理想栖息地。尽管这种海洋环节动物自20世纪50年代以来就在研究实验室中进行培养，并且有一个自由游动的幼虫阶段，但尚未确定诱导这种沙蚕幼虫沉降的特定环境线索。在这里，我们证明微藻生物膜是幼虫沉降的关键线索，它作为主要食物来源，诱导幼虫更早开始沉降，并促进随后幼体的生长。我们测试了幼虫对40种不同微藻菌株（主要是硅藻物种）的沉降反应，发现幼虫在选择沉降底物时有物种特异性偏好。诱导幼虫沉降最有效的硅藻物种是底栖羽纹硅藻，包括、和。确定幼虫沉降的特定环境线索，能够将其生态学与调节幼虫行为和发育的感觉和神经系统信号联系起来。将硅藻纳入幼虫培养实践将改善这种海洋无脊椎动物模型的养殖。
