Ecologia comportamental de Poecilia Sarrafae Bragança & Costa, 2011 (Cyprinodontiformes: poeciliidae)

Abstract

ABSTRACT This study investigates the behavioral ecology of Poecilia sarrafae, a freshwater fish endemic to the Northeastern region of Brazil, occurring in the Munim River basin, with the aim of filling knowledge gaps about its biology and behavior, as well as providing baseline data to support conservation strategies and policies. Research was conducted at three sites in the middle Munim River basin—Aldeia, Chororó, and Repouso do Guerreiro—characterized by distinct water flow regimes. Data collection spanned 14 months and included video recordings, population censuses, and physicochemical analyses of the water. The results demonstrate that water flow, bank structure, and predator presence directly influence spatial use as well as feeding and reproductive behaviors. Environments with slower flow and shallow marginal waters, such as Chororó, favored higher reproductive and feeding activity, although the constant presence of predators may have contributed to the lower frequency of courtship chases at this site. In contrast, the site with stronger flow (Aldeia) exhibited reduced frequencies of feeding and reproductive behaviors but an increased frequency of chases, particularly during the dry season, when the sex ratio was more balanced and no predators were recorded. During the rainy season, however, the increased occurrence of predators coincided with a reduction in chase behavior. Spatial restriction of females also contributed to prolonging the duration of these interactions. Moreover, an increase in female feeding frequency was observed at Aldeia during the rainy season, possibly related to greater energetic demands associated with reproductive interactions and enhanced resource availability. At sites with intermediate flow, such as Repouso do Guerreiro, chases were longer in duration but less frequent, likely due to the higher predator abundance recorded in this environment. The ethogram constructed revealed distinct behavioral patterns, highlighting variations in reproductive, feeding, and agonistic behaviors. Preliminary analyses further suggest that individual abundance and morphology significantly influence reproductive behavior, particularly under more stable environmental conditions. In addition, a negative association was observed between male chasing activity and female feeding frequency, indicating a potential behavioral cost of reproduction. Overall, the findings underscore the importance of the interplay among environmental factors, predation risk, and social composition in shaping the behavior of P. sarrafae, thereby offering novel insights into the behavioral ecology of poeciliids.