As predators, Naticidae (Gastropoda) can shape marine soft-sediment communities. Thus understanding of the reproductive biology and development of moonsnails is of great importance. Most moonsnails lay large egg masses, known as sand or egg collars, which are freely distributed on sand or muddy sediments. Here we report upon the abundance of egg collars of two naticid species, Amauropsis islandica and Euspira pallida, from the high-latitude White Sea, as well as describe the morphology of egg collars and hatching success, with a brief description of juvenile feeding in A. islandica. While in the subtidal zone, the egg collars of E. pallida were 10 times more abundant than of A. islandica, the egg collars of the latter species were the only ones that occur in the intertidal zone. The morphology of an egg collar of E. pallida differed from the literature descriptions by having a plicated basal margin. The number of egg capsules inside the collars was twice as high in A. islandica compared with E. pallida, but they were smaller. Amauropsis islandica hatchlings were larger and hatching success was more than twice that in E. pallida. We suggest that these characteristics promote the high abundance of A. islandica populations observed on some tidal flats of the White Sea. Surprisingly, A. islandica juveniles could perform non-drilling feeding in the first month after hatching. This study fills the gap in the knowledge of naticid reproductive biology at high latitudes.

中文翻译：

---

高纬度白海月螺孵化成功、发育时机和早期摄食行为

作为捕食者，蛞蝓科（腹足纲）可以塑造海洋软沉积物群落。因此，了解月螺的生殖生物学和发育非常重要。大多数月螺产下大块的卵块，称为沙子或卵环，它们自由分布在沙子或泥泞的沉积物中。在这里，我们报告了两种海虱物种的卵项圈的丰度，岛黑和苍白螺, 来自高纬度白海, 以及描述卵项圈的形态和孵化成功, 并简要描述了幼体在A. islandica. 在潮下带时，卵项圈E. pallida的数量是 的 10 倍A. islandica，后一种物种的蛋项圈是唯一出现在潮间带的蛋项圈。蛋项圈的形态E. pallida与文献描述的不同之处在于具有折叠的基底边缘。衣领内的卵囊数量是人类的两倍A. islandica和....相比E. pallida，但它们更小。岛黑孵化的体型更大，孵化成功率是当年的两倍多E. pallida. 我们认为这些特征促进了高丰度A. islandica在白海的一些潮滩上观察到的种群。出奇，A. islandica幼鱼在孵化后的第一个月可以进行非钻孔喂养。本研究填补了高纬度水螅生殖生物学知识的空白。