Ocorrência de paternidade múltipla em ninhadas de aruanã branco Osteoglossum bicirrhosum Cuvier, 1829 (Osteoglossiformes: Osteoglossidae)

Abstract

Monogamy is rare in fish and is usually associated with elaborate and prolonged parental care. Among fish, the male is usually responsible for parental care, and it is believed that there is a relationship between this high energetic investment and the certainty of paternity, but not when sneaker males occur. The silver arowana, Osteoglossum bicirrhosum, is considered monogamous and has special behavioral traits that allow the study of mating systems and parental care, such as mouthbrooding performed by males and formation of aggregations of males during parental care. Using microsatellite markers, we investigated the genetic relationships between males and the brood found in their oral cavity. Samples were collected on Sustainable Development Reserve Piagaçu-Purus, lower Purus River, Amazonas, Brazil. Fourteen broods were analyzed (268 young and 14 adult males) using eight microsatellite loci. The results indicate that most broods (11) show monogamous mating. Three broods had revealed the occurrence of multiple paternity. In one brood, about 50% of the young were genetically compatible with the male who was performing the parental care, and in the other two the genotypes of parents were not compatible with any of the young. The result of the first clutch may be explained by the interference of a sneaker male, whereas cooperative parental care may explain the lack of relationship between males and pups in the other two broods. We suggest that cooperative care may occur as brood mixing.