Non-genetic inheritance of stochastically induced behavioral individuality in a naturally clonal fish

Abstract

The study of among-individual phenotypic variation arising in the apparent absence of genetic and environmental differences has recently emerged as a rapidly growing research area. Despite growing recognition of its existence and fitness relevance, it remains unknown whether signatures of such presumably stochastically induced variation can be transmitted across generations. To address this knowledge gap, we performed a two-generation behavioral screening with a naturally clonal fish: 34 genetically identical mothers and their 232 offspring were separated after birth into near-identical environments, with early-life behavior being tracked continuously at high resolution, constituting a total of ~19,000 observation hours. We find consistent among-individual differences in behavior (i.e., activity and feeding patterns) in both mothers and offspring. Mother behavior correlates with offspring activity (but not offspring feeding): mothers that spend more time feeding produce more active offspring. We find no evidence of body size (maternal or offspring) mediating mother-offspring behavioral associations. Our study provides first evidence for the non-genetic transmission of among-individual phenotypic differences that arise in the apparent absence of genetic or environmental differences, highlighting the potential importance of this variation for evolutionary processes and the adaptive potential of populations.