Feeding patterns of the gastropod Lepsiella vinosa on the West Head rocky shore in Victoria

This study used observations of Lepsiella vinosa and surveys of prey species to describe the diet of L.vinosa on rocky shore at West Head, Victoria. The numbers of individual L.vionsa observed feeding were recorded during the surveys of Site 1 and Site 2 from 1975 to 1978 (see ?The population dynamics of the gastropod Lepsiella vinosa on the West Head rocky shore in Victoria? file identifier: 05f4f7f0-f49f-11dc-9f74-00188b4c0af8). In addition, six quadrats (25 x 25 cm) were randomly placed at the 2 sites every 2 months from March 1976 to January 1977. The number and size (measured to the nearest 0.01 cm) of prey species was recorded in each quadrat.

The number of L.vinosa recorded feeding varied seasonally and strongly correlated with the changes in density of prey species. In Area 1, L.vinosa was feeding on Littorina unifasciata for 66% of the observations and Littorina praetermissa, Bembicium nanum, Kellia australis, Nerita atramentosa, Chthamalus atennatus and Zenostrobus pulex for the remaining proportion of observations (n=895). In Area 2, there were fewer observations of feeding L.vinosa (n=53) with the same species recorded as prey items but the majority 34% of L.vinosa was feeding on Nerita atramentosa. Analyses of the data from the quadrats indicated that, in late summer and autumn, L.vinosa reduced its selectivity for prey species, compared to early winter and spring, when they targeted Littorina spp.

本研究通过对维多利亚州西岬岩岸的荔枝螺（Lepsiella vinosa）开展野外实地观测与猎物种类调查，明确了该螺类的食性组成。1975年至1978年期间，研究人员在1号样地与2号样地的调查中记录了正在觅食的荔枝螺个体数量（详见文献《维多利亚州西岬岩岸荔枝螺的种群动态》，文件标识符：05f4f7f0-f49f-11dc-9f74-00188b4c0af8）。此外，1976年3月至1977年1月期间，研究团队每2个月在两处样地随机布设6个25×25厘米的样方，记录每个样方内猎物种类的个体数量与尺寸（测量精度精确至0.01厘米）。
观测记录显示，正在觅食的荔枝螺数量存在季节性波动，且与猎物种群密度变化呈显著相关。在1号区域的895次觅食观测中，66%的记录显示荔枝螺以单一齿滨螺（Littorina unifasciata）为食，剩余34%的观测样本的捕食对象包括淡色滨螺（Littorina praetermissa）、矮小拟沼螺（Bembicium nanum）、澳大利亚凯利蛤（Kellia australis）、黑凹螺（Nerita atramentosa）、触角藤壶（Chthamalus atennatus）及蚤状泽囊藻（Zenostrobus pulex）。在2号区域，觅食观测记录较少，共53次，尽管捕食对象种类与1号区域一致，但其中34%的观测显示荔枝螺主要以黑凹螺为食。对样方数据的分析表明，与早冬和春季荔枝螺偏好捕食滨螺属（Littorina spp.）物种的食性选择模式相比，其在晚夏与秋季会降低对猎物的选择特异性。