Seasonal variation in the diet of Lontra longicaudis in the Paraná River basin, Argentina

Abstract

We studied the Neotropical otter (Lontra longicaudis) seasonal diet variations in the middle Paraná River valley, in central-northern Argentina, at the southern limit of its global range. We recorded 745 prey items in 320 scats collected over the course of 1 year in a tributary stream of the Paraná River. Fish, crustaceans, mammals, and insects were the most important items in frequency of occurrence among items. Other items, like mollusks, birds, amphibians, and reptilians were presented in low frequency in all seasons. We recorded seasonal variation in the frequency of the principal categories items: fish, mammals, crustaceans, and insects and in reptilian that had low frequency. Although fish were the most common items consumed by the otter, other groups such as crustaceans, mammals, and insects, were also important in the diet of the Neotropical otter throughout the seasons. Mammals and insects showed a higher frequency in the Neotropical otter diet in our study than in Brazil, Mexico, and even northern Argentina. We noted a marked variation throughout the Neotropical region in the niche breadth indices among studies of Neotropical otter's diet. The Shannon H′ diversity index showed a higher value in our study than in most of previous diet analyses of this species.

The Neotropical otter Lontra longicaudis: a comprehensive update on the current knowledge and conservation status of this semiaquatic carnivore

“…, Vezzosi et al. ), there have been important advances in the global fields of genetics and molecular biology in the last decades. These findings provide interesting insights into the levels of genetic diversity, population structure, evolution and ecology of the Neotropical otter (Trinca et al.…”

Unravelling the trophic guild structure of Neotropical Carnivora: diet specialisations, spatial variation and phylogenetic drivers

“…Otters are known to feed mainly on fish and crustaceans, items that are not very common in other carnivorans' diet (Medina‐Vogel et al 2004, Sousa et al 2013b, Silva et al 2014). However, when using order , the Neotropical otter ( Lontra longicaudis ) is allocated alone, possibly due to its wider diet variation, including arthropods and rodents as food resources (Vezzosi et al 2014).…”

“…For Pteronura brasiliensis , we found three dietary studies, all describing fish as the most consumed item, especially from Cichlidae and Characidae families (Rosas et al 1999, Cabral et al 2010, Silva et al 2014). Because of that, we considered Pteronura brasiliensis a specialist, and due to its fish‐based diet, modularity placed it with other otters, that mainly consume fish or crustaceans (Mangel et al 2011, Silva et al 2014, Vezzosi et al 2014). Ultimately, although in a bipartite plot, some felids could be considered generalists, modularity plots place most species in two modules, one mainly based on small mammal consumption, and the other on mammals heavier than 1 kg and reptiles.…”

Effects of acidification on the isotopic ratios of Neotropical otter tooth dentin

“…1 Despite its wide distribution, occurring throughout Central and South America, 2 it is a little studied species. Most of the studies about the Neotropical otter are focused on diet (e.g., [3][4][5] ) and habitat use (e.g., [6][7][8] ). However, the methodology applied in these works has limitations that can generate biases in results.…”