Department of Biology, University of Padova, Padova, Italy.
PLoS One. 2012;7(5):e37408. doi: 10.1371/journal.pone.0037408. Epub 2012 May 30.
Stalked and acorn barnacles (Cirripedia Thoracica) have a complex life cycle that includes a free-swimming nauplius larva, a cypris larva and a permanently attached sessile juvenile and adult barnacle. The barnacle cyprid is among the most highly specialized of marine invertebrate larvae and its settlement biology has been intensively studied. By contrast, surprisingly few papers have dealt with the critical series of metamorphic events from cementation of the cyprid to the substratum until the appearance of a suspension feeding juvenile. This metamorphosis is both ontogenetically complex and critical to the survival of the barnacle. Here we use video microscopy to present a timeline and description of morphological events from settled cyprid to juvenile barnacle in the model species Balanus amphitrite, representing an important step towards both a broader understanding of the settlement ecology of this species and a platform for studying the factors that control its metamorphosis. Metamorphosis in B. amphitrite involves a complex sequence of events: cementation, epidermis separation from the cypris cuticle, degeneration of cypris musculature, rotation of the thorax inside the mantle cavity, building of the juvenile musculature, contraction of antennular muscles, raising of the body, shedding of the cypris cuticle, shell plate and basis formation and, possibly, a further moult to become a suspension feeding barnacle. We compare these events with developmental information from other barnacle species and discuss them in the framework of barnacle settlement ecology.
蔓足类（甲壳纲 Thoracica）的藤壶和长鼻目有一个复杂的生命周期，包括自由游动的无节幼体、糠虾幼体和永久性附着的固着幼体和成年藤壶。藤壶的糠虾幼体是海洋无脊椎动物幼虫中最特化的之一，其定居生物学已被广泛研究。相比之下，令人惊讶的是，很少有论文涉及到从糠虾幼体的胶结到基质附着到出现悬浮喂养幼体的关键变态事件系列。这种变态既是个体发生上的复杂过程，也是藤壶生存的关键。在这里，我们使用视频显微镜展示了模型物种扁藤壶（Balanus amphitrite）从定居的糠虾幼体到幼藤壶的形态事件时间表和描述，这是朝着更广泛地了解该物种的定居生态学以及研究控制其变态的因素迈出的重要一步。B. amphitrite 的变态涉及一系列复杂的事件：胶结、表皮与糠虾表皮分离、糠虾肌肉退化、胸甲在套膜腔内旋转、幼体肌肉的构建、触角肌的收缩、身体抬起、糠虾表皮、壳板和基片的脱落，以及可能进一步蜕皮成为悬浮喂养的藤壶。我们将这些事件与其他藤壶物种的发育信息进行了比较，并在藤壶定居生态学的框架内对它们进行了讨论。
