Resposta de roedores à percepção do risco de predação

Abstract

Predation plays a crucial role in structuring and functioning ecosystems, influencing species composition, population dynamics and biodiversity. Beyond mortality, non-lethal effects of predation alter prey behavior, affecting habitat use, reproduction, and foraging. Risk perception is mediated through direct cues (physical signs left by potential predators) or environmental conditions that affect accurate danger assessment. Lunar luminosity is often considered a predation risk factor for nocturnal mammals, like rodents, which rely less on vision. Rainfall, promoting vegetation growth, seed and fruit production, and increased invertebrate activity, also impacts foraging, reproduction, and survival. From June 2023 to April 2024, we investigated how rodent foraging patterns respond to direct and indirect predation risk cues, testing three hypotheses: (1) rodents exhibit lunar phobia, altering foraging during full moon nights; (2) rodents avoid foraging in the presence of direct predator cues; (3) seasonal variation influences rodent foraging patterns. Using the Giving-up Density (GUD) method, we experimentally assessed sunflower seed removal rates during Full and New Moon phases in both dry and wet seasons in a dense Cerrado area, using Canis lupus familiaris scat as an indicator. Lunar phase was the most significant factor influencing consumption rates, which were 2.2 times higher during New Moon compared to Full Moon. Given that many predators are nocturnal and visually oriented, lower luminosity during New Moon may signal a safer environment. Combined with seasonal findings, rodents appear to prioritize broad environmental cues, such as luminosity and seasonal resource availability, over direct predator signals when assessing foraging costs versus needs, underscoring the importance of predation risk perception in shaping rodent foraging behavior and ecology. This highlights the role of multiple environmental factors in predator-prey interactions and underscores their impact on ecosystem dynamics.