Laboratorio de Reproducción y Biología Integrativa de Invertebrados Marinos (LARBIM)-IBIOMAR, CCT CONICET-CENPAT, Puerto Madryn, Chubut, Argentina.
Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile, Valdivia, Chile.
PLoS One. 2021 Apr 30;16(4):e0250937. doi: 10.1371/journal.pone.0250937. eCollection 2021.
Active predators obtain energy and nutrients from prey through complex processes in which the energy gained must exceed the energy invested in finding and ingesting the prey. In addition, the amount of energy available will vary with the prey that are selected for consumption. The muricid gastropod Acanthina monodon inhabits rocky shores, where it routinely feeds on the mytilids Semimytilus algosus and Perumytilus purpuratus. In this study, S. algosus was highly preferred by the predator (over 90% were eaten) versus P. purpuratus (only 9% were eaten) when offered a mixed diet. The energetic cost of attacking one S. algosus individual was 91 J bivalve-1 while for P. purpuratus it was slightly higher: 95 J bivalve-1. Also, whereas A. monodon required on average 19 h to consume S. algosus, successful attacks on P. purpuratus required about 32% more time (25 h). In addition, a longer resting time was needed by the predator after preying on P. purpuratus before it initiated another attack. Moreover, the active metabolic costs associated with successfully attacking the prey increased 3.2 times over the basal metabolic costs when attacking S. algosus, but only by 2.5 times when attacking P. purpuratus. The calculations associated with preying on each species showed that the energetic gain per unit time likely accounts for the predator's preference for attacking S. algosus, even though predation on both species provided net energy gains for the predator. However, as S. algosus occurs seasonally at our study site, P. purpuratus would probably also be consumed due to its constant availability throughout the whole year.
主动掠食者通过复杂的过程从猎物中获取能量和营养，在这个过程中，获得的能量必须超过寻找和摄入猎物所消耗的能量。此外，可用能量的多少还会因选择食用的猎物而有所不同。居住在岩石海岸的肉食性腹足纲软体动物 Acanthina monodon 经常以贻贝 Semimytilus algosus 和 Perumytilus purpuratus 为食。在这项研究中，当提供混合饮食时，掠食者更倾向于食用 S. algosus（超过 90%被吃掉），而不是 P. purpuratus（只有 9%被吃掉）。攻击一个 S. algosus 个体的能量成本为 91 J 双壳类动物-1，而对于 P. purpuratus 则略高：95 J 双壳类动物-1。此外，A. monodon 平均需要 19 小时来消耗 S. algosus，而成功攻击 P. purpuratus 则需要多花约 32%的时间（25 小时）。此外，在捕食 P. purpuratus 后，掠食者需要更长的休息时间，然后才能再次发起攻击。此外，当捕食 S. algosus 时，成功攻击猎物相关的主动代谢成本比基础代谢成本增加了 3.2 倍，但捕食 P. purpuratus 时仅增加了 2.5 倍。对每种猎物进行的捕食计算表明，单位时间内的能量收益可能是掠食者更倾向于攻击 S. algosus 的原因，尽管捕食这两种猎物都为掠食者提供了净能量收益。然而，由于 S. algosus 在我们的研究地点季节性出现，P. purpuratus 也可能会被吃掉，因为它在全年都有供应。
