Rearing-Group Size Determines Social Competence and Brain Structure in a Cooperatively Breeding Cichlid

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. abstract: Social animals can greatly benefit from well-developed social skills. Because the frequency and diversity of social interactions often increase with the size of social groups, the benefits of advanced social skills can be expected to increase with group size. Variation in social skills often arises during ontogeny, depending on early social experience. Whether variation of social-group sizes affects development of social skills and related changes in brain structures remains unexplored. We investigated whether, in a cooperatively breeding cichlid, early group size (1) shapes social behavior and social skills and (2) induces lasting plastic changes in gross brain structures and (3) whether the development of social skills is confined to a sensitive ontogenetic period. Rearing-group size and the time juveniles spent in these groups interactively influenced the development of social skills and the relative sizes of four main brain regions. We did not detect a sensitive developmental period for the shaping of social behavior within the 2-month experience phase. Instead, our results suggest continuous plastic behavioral changes over time. We discuss how developmental effects on social behavior and brain architecture may adaptively tune phenotypes to their current or future environments.

Transcriptomic signatures of social experience during early development in a highly social cichlid fish

“…Our results suggest that alterations of gene expression and the neurogenomic state of stress reported here influence the dissimilar developmental trajectories between juveniles of +F and −F fish (Fischer et al, ) and may explain why these trajectories already start to diverge very early in development. Moreover, our results corroborate previous findings of behavioural changes during the first two months of life in N. pulcher (Arnold & Taborsky, ; Fischer et al, , ; Taborsky et al, ). Future studies will reveal whether the observed expression differences are also causally related to age‐dependent social behavioural changes during early development, and whether these gene expression differences are transient or permanent.…”

“…N. pulcher possess a large and refined repertoire of affiliative, submissive and aggressive social behaviours used to navigate the complexities of their social environment (Taborsky & Oliveira, ), helping to resolve within‐group conflict and to maintain group stability (Taborsky, ; Taborsky & Taborsky, ). The early social environment during the first two months after reaching the fry stage strongly influences the ability to express this behavioural repertoire in an appropriate, context‐specific manner (Arnold & Taborsky, ; Fischer et al, ; Nyman et al, , ; Taborsky et al, ).…”

Effect of the early social environment on behavioural and genomic responses to a social challenge in a cooperatively breeding vertebrate

“…, ; Fischer et al . ). Afterwards, the parents and the helper were removed from the +F treatment and were transferred back to the institute's breeding stock.…”

“…Fischer et al . ) and can be mediated by organizational effects of hormones or epigenetic modifications. Organizational effects of the hormonal system (Phoenix et al .…”

Opening the Black Box of Developmental Experiments: Behavioural Mechanisms Underlying Long‐Term Effects of Early Social Experience

“…; Fischer et al. ). Social complexity was manipulated by either rearing the fish in groups without (young siblings only) or with age structure (parents, helpers and young siblings), or in small (parents plus one helper) vs. large groups (parents plus many helpers).…”