Settlement cue selectivity by larvae of the destructive crown-of-thorns starfish

This study assessed the relative capacity of a diversity of coralline algae to induce COTS settlement in order to test the hypothesis that the alga Lithothamnion cf. proliferum promotes higher settlement rates than the other species. Western Pacific COTS (Acanthaster cf. solaris) larvae were reared at the Australian Institute of Marine Science (AIMS) National Sea Simulator. Larval development was microscopically examined until metamorphic competency 14 days post-fertilization was determined. Experimental treatments included 14 living coralline algae species and one living Peyssonneliaceae alga plus structural control (sterile aragonite) and filtered seawater (FSW) control treatments. 12 replicate settlement assays were conducted for each of the 17 experimental treatments with six well cell culture plates, and fully randomised distrubution of all replicate assays among the 204 wells. After adding 10 ml FSW and a single chip of one of 15 different algal species or sterile aragonite to the wells, approximately 10 competent COTS larvae per well were introduced using glass pipettes. All well plates were kept in a temperature-controlled room (28°C) matching the light conditions during larval rearing (12 L : 12 D, light–dark).Larval settlement was scored 24 and 48 h after larvae were introduced using stereo microscopes. Scoring included:    the number of competent late-brachiolaria larvae remaining in the water column (= swimming)    he number of individuals that had successfully attached to the treatment chip or well bottom and commenced or completed metamorphic transformation into a juvenile with radial symmetry (= settled)Statistical analyses were performed using R software (v. 4.1.3). The molecular sequences for each algal species can be accessed in the GenBank database under accession numbers OP830444 to OP830473species | psbA GenBank accession No. | rbcL GenBank accession No.Melyvonnea cf. madagascariensis | OP830452 | OP830467Neogoniolithon fosliei | OP830450 | OP830465Adeylithon bosencei | OP830454 | OP830469Hydrolithon cf. reinboldii | OP830457 | OP830472Lithophyllum cf. insipidum | OP830456 | OP830471Lithothamnion cf. proliferum | OP830448 | OP830463Titanoderma cf. tessellatum | OP830447 | OP830462Amphiroa foliacea | OP830453 | OP830468Sporolithon sp. | OP830455 | OP830470Ramicrusta sp. | OP830458 | OP830473Lithophyllum cf. pygmaeum | OP830449 | OP830464Porolithon sp. A | OP830446 | OP830461Porolithon sp. B | OP830444 | OP830459Lithophyllum cf. kotschyanum | OP830451 | OP830466Porolithon sp. | C OP830445 | OP830460Experimental assay data and description are available from the Dryad Digital Repository linked below.

本研究旨在评估多种珊瑚藻诱导棘冠海星（Crown-of-Thorns Starfish，COTS）定居的相对能力，以验证“拟增殖石藻（Lithothamnion cf. proliferum）较其他珊瑚藻可诱导更高定居率”这一假说。
西太平洋棘冠海星（Acanthaster cf. solaris）幼虫于澳大利亚海洋科学研究所（Australian Institute of Marine Science，AIMS）国家海洋模拟设施中饲养。通过显微镜观察幼虫发育情况，直至受精后14天确定其具备变态附着能力。
实验处理组涵盖14种活珊瑚藻、1种活皮丝藻科（Peyssonneliaceae）藻类，另设结构对照（无菌文石）与过滤海水（Filtered Seawater，FSW）对照组，共计17种实验处理。针对17种实验处理组，本研究采用6孔细胞培养板开展12次重复定居实验，并将所有重复实验样本完全随机分配至204个孔位中。向每个孔中加入10ml过滤海水与1片取自15种藻类或无菌文石的样本后，使用玻璃移液管向每孔接种约10只具有附着能力的棘冠海星幼虫。所有培养板均置于控温28℃的房间中培养，光照条件与幼虫饲养阶段一致（12小时光照：12小时黑暗，即12L:12D光暗周期）。
接种幼虫后24小时与48小时，通过体视显微镜对幼虫定居情况进行评分，评分指标包括：① 仍留存于水体中的具有附着能力的晚期腕幼体数量（即游泳个体）；② 成功附着于处理样本或孔底，并已启动或完成变态发育为辐射对称稚海星体的个体数量（即已定居个体）。
本研究采用R软件（版本4.1.3）开展统计分析。所有珊瑚藻的分子序列可通过GenBank数据库获取，登录号为OP830444至OP830473：
| 物种名称 | psbA基因GenBank登录号 | rbcL基因GenBank登录号 |
| ---- | ---- | ---- |
| 拟马达加斯加梅利文藻（Melyvonnea cf. madagascariensis） | OP830452 | OP830467 |
| 新结壳珊瑚藻（Neogoniolithon fosliei） | OP830450 | OP830465 |
| 博森氏阿德伊石藻（Adeylithon bosencei） | OP830454 | OP830469 |
| 拟莱因博尔德水石藻（Hydrolithon cf. reinboldii） | OP830457 | OP830472 |
| 拟平淡石叶藻（Lithophyllum cf. insipidum） | OP830456 | OP830471 |
| 拟增殖石藻（Lithothamnion cf. proliferum） | OP830448 | OP830463 |
| 拟棋盘泰坦藻（Titanoderma cf. tessellatum） | OP830447 | OP830462 |
| 叶状仙掌藻（Amphiroa foliacea） | OP830453 | OP830468 |
| 孢石藻未定种（Sporolithon sp.） | OP830455 | OP830470 |
| 分支壳藻未定种（Ramicrusta sp.） | OP830458 | OP830473 |
| 拟矮小石叶藻（Lithophyllum cf. pygmaeum） | OP830449 | OP830464 |
| 多孔石藻未定种A（Porolithon sp. A） | OP830446 | OP830461 |
| 多孔石藻未定种B（Porolithon sp. B） | OP830444 | OP830459 |
| 拟科奇安石叶藻（Lithophyllum cf. kotschyanum） | OP830451 | OP830466 |
| 多孔石藻未定种C（Porolithon sp. C） | OP830445 | OP830460 |
本实验的检测数据与详细说明可通过下方链接指向的Dryad数字知识库获取。