Is predation of juvenile crown-of-thorns seastars (Acanthaster cf. solaris) by peppermint shrimp (Lysmata vittata) dependent on age, size, or diet?

Ten predation experiments were carried out examine whether predation of juvenile CoTS by peppermint shrimp (L. vittata) is affected by the age, size, or diet of juvenile CoTS.Over a span of 9.5 months, ten experiments were carried out with juvenile CoTS ranging from 1 to 9 months of age and 0.34 mm and 21.37 mm in diameter. Juvenile CoTS were reared and fed a diet of either CCA throughout the experiments or corals (introduced at 4 months, and only offered from around 5 months ). Shrimps assessed for health status, measured with callipers to the nearest millimetre (from rostrum to tail) and left to acclimatize unfed in 250 ml jars for two–three days as suggested for invertebrate gut content analysis experiments, (5–16 per experimental run, depending on availability).On the fourth day, a single juvenile CoTS was measured (maximum diameter, with callipers) and introduced into each jar. The jars were monitored daily for the following three days. The condition of the juvenile CoTs was scored as:    None – if there was not change in appearance    Partial predations – if they were alive but had missing limbs or injuries    Lethal predation – if they had been fully consumed by the predator.Data analysis examined the effects of CoTS size and age on the incidence of partial and lethal predation.

本研究共开展10次捕食实验，旨在探究薄荷虾（peppermint shrimp，L. vittata）对幼体棘冠海星（juvenile CoTS）的捕食行为是否受其年龄、体型及日粮组成的影响。
实验周期共计9.5个月，所用幼体棘冠海星的年龄介于1至9月龄，体直径范围为0.34 mm至21.37 mm。
实验全程中，幼体棘冠海星分为两组日粮：一组全程以壳状珊瑚藻（Crustose Coralline Algae，缩写CCA）为食；另一组于第4月龄引入珊瑚作为饵料，且仅在约5月龄后开始提供。
实验前需对薄荷虾进行健康状况评估，使用游标卡尺测量其从额剑至尾节的体长，精确至毫米；随后将虾放入250 mL广口瓶中，禁食驯化2至3天——该操作参考无脊椎动物肠道内容物分析实验的标准流程，每次实验投放的虾数量为5至16只，视实际可获取量而定。
实验第4天，先用游标卡尺测量单只幼体棘冠海星的最大体直径，随后将其放入各广口瓶中。之后连续3天每日监测瓶内实验对象的状态。
幼体棘冠海星的状态被分为以下三类评分：
1. 无变化（None）：外观无任何异常改变；
2. 部分捕食（Partial predations）：个体仍存活，但存在肢体缺失或损伤；
3. 致死性捕食（Lethal predation）：个体已被捕食者完全吞食。
数据分析环节旨在探究幼体棘冠海星的体型与年龄对部分捕食及致死性捕食发生率的影响。