The impact of exposure to different environmental complexities on spatial cognition and neuroanatomy in guppy fish (Poecilia Reticulata) at two different age stages

Abstract

Brain size and anatomy, and thus cognition can vary greatly due to demands of the environment. These changes can occur either because of plasticity or adaptation. In this study we aim to investigate the effects of environmental complexity on spatial cognition and neuroanatomy in guppy fish (Poecilia Reticulata). We exposed guppies to three environments of varying complexity levels at two different life stages and conducted spatial cognition tests in a maze to evaluate whether the brain and spatial cognition show evidence of change through brain plasticity. Despite a display of learning behavior in a maze experiment, the results do not substantiate the hypothesis that increased environmental complexity significantly influences spatial cognition or triggers neuroanatomical changes. While there were some differences in spatial cognition skills between males and females in the juvenile group, these differences were not significant in adult fish. These findings show that other unmeasured factors may have a greater impact on spatial cognition and morphological adaptations in these species, casting doubt on the premise that higher environmental complexities directly promote structural or functional adaptations in guppy fish.