Freshwater mysids of the Mysis relicta group are omnivorous macroinvertebrates that form an important link between fishes and lower trophic levels in many north temperate to Arctic lakes, where they exhibit diel vertical migration (DVM) to exploit subsurface food-rich layers at night. Benthic food resources have been assumed to be less important for mysid diets than pelagic zooplankton. Studies have nevertheless indicated that mysids consume benthic sedimented detritus, calling this assumption into question. We conducted a food-choice experiment to evaluate the feeding preferences of Mysis diluviana (Audzijonyte & Väinölä, 2005) by presenting field-caught specimens in individual foraging arenas with multiple choices of food. Experimental food treatments included a preferred pelagic prey (Daphnia), a presumed less desirable benthic resource (detritus), and a combination of both. We hypothesized that M. diluviana 1) prefers Daphnia over detritus and consumes only Daphnia in combination treatments, and 2) would not consume detritus except when detritus was the only food source available. Contrary to our hypothesis, M. diluviana readily consumed detritus in the presence of Daphnia. Mysis diluviana unexpectedly consumed more individuals of Daphnia in the presence rather than in the absence of detritus. Our results demonstrate that mysids take advantage of benthic food resources even in the presence of a presumably preferred zooplankton prey, calling to question the long-held assumption that benthic resources are unimportant when considering the trophic role of freshwater mysids of the M. relicta group.

中文翻译：

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淡水糠糠diluviana（Audzijonyte＆Väinölä，2005年）（Mysida：Mysidae）消耗碎屑在存在水蚤（枝角类：Daphniidae）

Mysis relicta组的淡水类mysids是杂食性大型无脊椎动物，在许多北方温带至北极湖的鱼类和较低营养水平之间形成了重要的联系，在那里它们表现出垂直垂直迁移（DVM），可在夜间利用地下富含食物的层。人们认为，对虾类食物来说，底栖食物资源的重要性不如浮游动物。然而，研究表明，类鸦片消耗了底栖沉积碎屑，这使这一假设受到质疑。我们进行了一项食物选择实验以评估Mysis diluviana的喂养偏好（Audzijonyte＆Väinölä，2005），通过在各个觅食场中呈现田野捕获的标本，提供多种食物。实验性食物处理包括首选的远洋猎物（Daphnia），假定的不太理想的底栖资源（碎屑）以及两者的结合。我们假设Diluviana 1）比碎屑更喜欢水蚤，并且在联合治疗中仅消耗水蚤； 2）不会消耗碎屑，除非碎屑是唯一可用的食物来源。与我们的假设相反，M。diluviana在水蚤存在时很容易消耗碎屑。Diluviana菌意外地消耗了更多的水蚤在存在而不是在没有碎屑的情况下。我们的结果表明，即使存在可能是首选的浮游生物捕食者的情况下，龙虾也能利用底栖食物资源，这使人们质疑长期以来一直认为底栖动物资源不重要的假设，而这种假设是考虑到利什曼原虫群的淡水虾类的营养作用。