The present study investigated the biological basis of cannibalism in Pseudoplatystoma reticulatum. Newly-hatched P. reticulatum were reared under a standard rearing protocol up to 50 days after hatching (DAH). Fish samples were periodically collected to construct a predictive model of the morphological limits of cannibalism. This model was further validated by the outcomes of a pairwise predation trial where cannibals were challenged with different prey sizes. Replicated small-scale cultures were carried-out in parallel to assess the ontogeny and dynamics of cannibalism. The predictive model showed that P. reticulatum cannibals are able to ingest prey from 77 to 85% of their own size. All ingested prey during the pairwise predation trial remained below the maximum prey size estimated by the predictive model, indicating model reliability. Three types of mortalities were distinguished during the early life stages of P. reticulatum: mortality owing to causes other than cannibalism (OM), incomplete cannibalism (ICM, half-ingested fish), and complete cannibalism (CCM, missing fish), each one impacting the population at different stages. By 50 DAH, survival was 21.32 ± 1.50% of the initial population, with the three types of mortalities impacting the population at similar levels (P > 0.05). The outcomes of this study progress our understanding of the biological basis of cannibalism and contribute towards advancing the rearing technologies of native fish species in South America.

本研究调查了食人网假食嘴虫的食人症的生物学基础。在标准孵化方案下，将新孵化的网状斑节对虾孵化至孵化后长达50天（DAH）。定期收集鱼样本，以构建食人族形态极限的预测模型。配对捕食试验的结果进一步验证了该模型，在该试验中，食人族面临着不同猎物大小的挑战。平行进行复制的小规模培养，以评估同类相食的发生和动力学。预测模型表明网纹假单胞菌食人族可以摄取自己大小的77％至85％的猎物。在成对捕食试验期间，所有摄入的猎物均保持低于预测模型估计的最大猎物大小，表明模型的可靠性。在网状疟原虫的生命早期，区分了三种类型的死亡率：由于非食人性（OM）引起的死亡率，不完全食人性（ICM，半食鱼）和完全食人性（CCM，失踪鱼），每一种在不同阶段影响人口。到50 DAH时，生存率为初始人口的21.32±1.50％，三种死亡率在相似的水平上影响着人口（P > 0.05）。这项研究的结果增进了我们对同类相食的生物学基础的理解，并有助于发展南美本地鱼类物种的饲养技术。