Diet of Moenkhausia bonita (Benine, Castro & Sabino 2004) (Characiformes: Characidae) in streams in the basin of rio Formoso, Brazilian Midwest

Abstract: To characterize the diet composition of Moenkhausia bonita and its temporal and ontogenetic variations in streams in the Formoso River basin (MS). The samples were collected in seven streams on two occasions throughout the year (dry and rainy seasons). The food items were analyzed according to the volumetric and occurrence frequency methods and the diet was characterized through the Food Index (IAi%). To determine ontogeny, the specimens were divided into five size classes in the dry (S1 to S5) and rainy (C1 to C5) seasons. To verify the difference between the species’ diet between the size classes and the seasons of the year, the Permutational Multivariate Analysis of Variance – PERMANOVA analysis was performed. Moenkhausia bonita was classified as an invertivore when it consumed basically both aquatic and terrestrial invertebrates (99.5% of the diet), with higher consumption of aquatic invertebrates. There was a significant difference in the diet of between the dry and rainy periods, and although the species basically consumed the same items in the two studied seasons, the proportions were different and there was no difference in the diet between size classes. M. bonita diet is based on autochthonous resources regardless of the size class, but that there were different consumption patterns when comparing the different seasons of the year. The present study provided information on the feeding of M. bonita and on its diet spectrum in different size classes and periods of the year, enabling a better understanding of the species, the importance of invertebrates in its diet, and the need for future studies on the biology, autoecology, and behavior of this species.

摘要：本研究旨在表征莫氏鲢（Moenkhausia bonita）在福尔莫索河盆地（MS）溪流中的食性组成及其随时间和个体发育而发生的变异。样品在一年中的两个时段（干季和雨季）的七条溪流中采集。食物项目根据体积和出现频率方法进行分析，并通过食物指数（IAi%）对食性进行特征化。为确定个体发育，样本在干季（S1至S5）和雨季（C1至C5）中被划分为五个大小类别。为了验证物种食性在不同大小类别和年度季节之间的差异，进行了置换多元方差分析（PERMANOVA分析）。当莫氏鲢主要摄食水生和陆生无脊椎动物（占食性的99.5%）时，被归类为杂食性，其中水生无脊椎动物摄食量更高。在干季和雨季之间，食性存在显著差异，尽管物种在这两个研究季节中基本上摄食相同的食物项目，但其比例不同，且大小类别之间食性无差异。莫氏鲢的食性基于自生资源，无论大小类别如何，但在不同季节间的摄食模式存在差异。本研究提供了关于莫氏鲢的摄食信息及其在不同大小类别和年度时期的食性谱，有助于更深入地理解该物种，了解无脊椎动物在其食性中的重要性，以及未来对该物种生物学、自生生态学和行为研究的必要性。