Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America.
Monterey Bay Aquarium Research Institute, Moss Landing, California, United States of America.
PLoS One. 2018 Nov 28;13(11):e0207249. doi: 10.1371/journal.pone.0207249. eCollection 2018.
Pelagic crustaceans are arguably the most abundant group of metazoans on Earth, yet little is known about their natural behavior. The deep pelagic shrimp Hymenopenaeus doris is a common decapod that thrives in low oxygen layers of the eastern Pacific Ocean. When first observed in situ using a remotely operated vehicle, most specimens of H. doris appeared dead due to inactivity and inverted orientation. Closer inspection revealed that these animals were utilizing small, subtle shifts in appendage position to control their orientation and sink rate. In this mode, they resembled molted shrimp exoskeletons. We hypothesize that these shrimp may avoid capture by visually-cued predators with this characteristic behavior. The low metabolic rates of H. doris (0.55-0.81 mg O2 kg-1 min-1) are similar to other deep-living shrimp, and also align with their high hypoxia tolerance and reduced activity. We observed similar behavior in another deep pelagic decapod, Petalidium suspiriosum, which transiently inhabited Monterey Canyon, California, during a period of anomalously warm ocean conditions.
远洋甲壳动物无疑是地球上最丰富的后生动物群体之一，但人们对它们的自然行为知之甚少。深海虾类 Hymenopenaeus doris 是一种常见的十足目动物，在东太平洋的低氧层中茁壮成长。当首次使用远程操作车辆在现场观察时，由于不活动和倒置的方向，大多数 H. doris 标本看起来已经死亡。仔细观察发现，这些动物正在利用微小的、微妙的附肢位置变化来控制它们的方向和下沉速度。在这种模式下，它们类似于蜕皮的虾类外骨骼。我们假设这些虾类可能会通过这种特征行为来避免被视觉线索的捕食者捕获。H. doris 的低代谢率（0.55-0.81 mg O2 kg-1 min-1）与其他深海虾类相似，也与它们对高缺氧的耐受性和活动减少相一致。我们在另一种深海甲壳类动物 Petalidium suspiriosum 中观察到了类似的行为，这种动物在加利福尼亚州蒙特雷峡谷的异常温暖的海洋条件下短暂栖息。
