施氏獭蛤幼虫和稚贝发育及行为的研究

Development and Behavior of the Larvae and Juveniles of Lutraria sieboldii Reeve

进行了施氏獭蛤(Lutraria sieboldii Reeve)的人工育苗、幼虫发育及行为观察实验。结果显示:在施氏獭蛤幼虫发育过程中,壳顶后期幼虫只有鳃丝及足出现,而没有眼点出现,发达的足和鳃丝是幼虫变态的标志;幼虫变态期明显的分为3～5d的爬行期和3～5d的附着期;爬行期幼虫有单条水管形成,附着期幼虫只有一条分叉的足丝,水管为单管型;底栖稚贝期开始形成两条水管,底栖稚贝早期的幼虫不具备潜沙能力,只进行爬行活动,随着水管的快速发育,幼虫逐渐具备潜沙能力,幼虫壳长达2500μm、水管长达6000μm以上时,最终具备和成体一样的完全潜沙能力。

Observation of the larval development and behavior of Lutraria sieboldii Reeve was undertaken in the Experimental Base of Guangdong Ocean University, Tandou township, Leizhou. Results showed that in the larval developmental course of Lutraria sieboldii Reeve, there was no eye-spot larval stage, only foot and ctenidia appeared at the late of pediveliger stage,developed foot and ctenidia were the mark of larval metamorphosis. The metamorphic period could be clearly divided into two developmental stages： crawling stage （3-5 days） and attaching stage （3-5 days）. Only single siphon was formed in crawling stage, larvae had a fork-shaped byssus and a single siphon in attaching stage. Juveniles began benthonic living with the formation of double siphon. At the early stage, juveniles did not possess the ability to bore in sand, and only had crawling behavior. With the rapid development of siphon and foot, juveniles gradually possessed the ability to bore in sand. When the shell length was more than 2 500 μm and siphon was more than 6 000 μm, larvae began to possess the capability to bore and entirely immerse its body under sand only with the end of siphon outside sand, just as its adult.