Diluzio Amber R, Baliga Vikram B, Higgins Benjamin A, Mehta Rita S
Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California Santa Cruz, Santa Cruz, CA 95060, USA.
Department of Ecology and Evolutionary Biology, Long Marine Laboratory, University of California Santa Cruz, Santa Cruz, CA 95060, USA.
Zoology (Jena). 2017 Jun;122:80-89. doi: 10.1016/j.zool.2017.03.002. Epub 2017 Mar 8.
Moray eels comprise a large radiation of elongate marine predators that are thought to swallow large prey whole but also circumvent gape constraints by manipulating prey into more manageable pieces. Prey manipulation behaviors include shaking, rotation, knotting, and ramming prey against another object to assist in swallowing. Most morays feed on a wide variety of prey that vary in mechanical properties such as stiffness and toughness, which could potentially affect feeding behaviors. There is little diet data informing us of the maximum prey size morays can swallow whole and whether maximum prey size differs between prey types. Our study examines feeding behaviors for the California moray (Gymnothorax mordax) in the laboratory. We recorded morays feeding on freshly thawed fish and cephalopods of varying size. We found that prey size had a strong effect on total feeding time and manipulation duration for both fish and cephalopods. While morays were observed using a diversity of prey manipulation behaviors and the durations for each of these behaviors increased with prey size, prey type had no effect on manipulation behaviors employed. Total manipulation duration, however, comprised a greater proportion of total feeding time for fish compared to cephalopods. As relative prey mass (RPM) increased for cephalopods, morays spent a greater proportion of their total feeding time transporting prey. Transport rate was higher for cephalopod prey but the relationship between RPM and transport rate was negative for both prey types. Despite this decrease in transport rate, we attribute the lower total feeding times for larger cephalopod prey compared to fish to behavioral tactics of morays. Morays used the corners of the aquaria to aid in the transport of larger cephalopod prey. We hypothesize that the deformable tissues of cephalopods and the presumably low coefficient of friction of their thawed mantles and tentacles may be difficult for the recurved teeth on the pharyngeal jaws to pierce and grip during transport.
海鳝是一大类细长的海洋捕食者，它们被认为会将大型猎物整个吞下，但也会通过将猎物处理成更易于处理的小块来规避口裂限制。猎物处理行为包括摇晃、旋转、打结以及将猎物撞击另一个物体以协助吞咽。大多数海鳝以各种具有不同机械特性（如硬度和韧性）的猎物为食，这可能会潜在地影响进食行为。目前几乎没有饮食数据能告诉我们海鳝能整个吞下的最大猎物尺寸，以及不同猎物类型的最大猎物尺寸是否存在差异。我们的研究在实验室中考察了加州海鳝（Gymnothorax mordax）的进食行为。我们记录了海鳝进食刚解冻的不同大小的鱼类和头足类动物的情况。我们发现猎物大小对鱼类和头足类动物的总进食时间和处理持续时间都有很大影响。虽然观察到海鳝使用多种猎物处理行为，并且这些行为的持续时间都随着猎物大小增加，但猎物类型对所采用的处理行为没有影响。然而，与头足类动物相比，鱼类的总处理持续时间在总进食时间中所占比例更大。随着头足类动物的相对猎物质量（RPM）增加，海鳝在总进食时间中用于运输猎物的比例更大。头足类猎物的运输速度更高，但两种猎物类型的RPM与运输速度之间的关系都是负相关。尽管运输速度有所下降，但我们将较大的头足类猎物与鱼类相比总进食时间较短归因于海鳝的行为策略。海鳝利用水族箱的角落来协助运输较大的头足类猎物。我们推测，头足类动物的可变形组织以及它们解冻后的外套膜和触手可能具有的低摩擦系数，可能使咽颌上的弯曲牙齿在运输过程中难以刺穿和抓握。
