COS 95-4 - CANCELLED - Developmental behavioral plasticity in shoaling induced by predation stress in Trinidadian guppies (Poecilia reticulata)

Abstract: Early-life experiences may be predictive of experiences later in life, potentially giving individuals the opportunity to prime their behaviour to match the environment. However, the mechanism underlying this developmental behavioural plasticity remains unknown. Epigenetics, such as DNA methylation (DNAm), offers a link between the environment and the genome that could possibly explain this. Trinidadian guppies (Poecilia reticulata) are small social fish that exhibit changes in life histories and behaviour associated with varying predation pressure. Guppies exposed to predation typically are found to show increased schooling, neophobia, and boldness. Guppies also respond strongly to alarm cue, a substance released during mechanical damage to the skin of many fish species that can reliably predict predation threat in the environment. The goals of this study were to investigate the impact of early-life exposure to predation stress on behaviour and DNAm in the brain. To do this, we exposed guppies to either alarm cue, inducing predation stress, or control sham cue throughout development and then we subjected them to two behavioural assays: an open-field, which measures boldness and exploratory behaviours, and a shoaling test, which measures grouping behaviour. Following assays, we removed brains and extracted DNA which was used for whole genome bisulfite sequencing. We found that guppies exposed to alarm cue during development significantly increased shoaling, however, there were no significant effects on behaviours measured in the open field test. The shift in shoaling behaviour in alarm cue exposed guppies matches behaviours seen in naturally occurring high predation populations suggesting that developmental plasticity may be used to adaptively prime behaviour to match predation environment. DNAm data analysis has uncovered 82437 differentially methylated sites that may be associated with alarm cue exposure. Further analysis is underway and will allow us to uncover DNAm responses to early-life stress and investigate relationships between variation in DNAm and behaviour. In conclusion, this study has shown how developmental plasticity may be used to adaptively prime behaviour in response to early-life predation stress and will investigate whether changes in DNAm underlie this developmental plasticity.