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.\n\nThe 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红纹滨螺（Lepsiella vinosa）的野外观测以及猎物种群调查，阐明了该腹足类的食性特征。1975年至1978年间，研究人员在1号样地与2号样地开展调查期间，记录了正在觅食的红纹滨螺个体数量（相关背景可参阅文件标识符为05f4f7f0-f49f-11dc-9f74-00188b4c0af8的文献《维多利亚州西岬岩岸红纹滨螺的种群动态》）。此外，1976年3月至1977年1月期间，研究人员每2个月便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体型（测量精度精确至0.01厘米）。

调查数据显示，正在觅食的红纹滨螺数量存在显著季节性波动，且与猎物种群密度的变化呈强相关性。在1号区域，总计895条观测记录中，66%的记录表明红纹滨螺以单齿滨螺（Littorina unifasciata）为食，其余观测样本的捕食对象包括普氏滨螺（Littorina praetermissa）、小纹蜒螺（Bembicium nanum）、澳大利亚凯利蛤（Kellia australis）、黑凹螺（Nerita atramentosa）、狭壳柱藤壶（Chthamalus atennatus）与丛状串珠藻（Zenostrobus pulex）。在2号区域，红纹滨螺的觅食观测记录较少（n=53），虽猎物种类与1号区域一致，但其中占比最高的34%的个体以黑凹螺为食。对样方数据的分析结果表明，相较于冬末与春季红纹滨螺专性捕食滨螺属（Littorina spp.）物种的情况，夏末与秋季时该螺类对猎物的选择性会显著降低。